Catalytic subunit of DNA polymerase gamma solely responsible for replication of mitochondrial DNA (mtDNA). Replicates both heavy and light strands of the circular mtDNA genome using a single-stranded DNA template, RNA primers and the four deoxyribonucleoside triphosphates as substrates (PubMed:11477093, PubMed:11897778, PubMed:15917273, PubMed:19837034, PubMed:9558343). Has 5' -> 3' polymerase activity. Functionally interacts with TWNK and SSBP1 at the replication fork to form a highly processiv

MitochondrionMitochondrion matrix, mitochondrion nucleoid

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant, 1

A disorder characterized by progressive weakness of ocular muscles and levator muscle of the upper eyelid. In a minority of cases, it is associated with skeletal myopathy, which predominantly involves axial or proximal muscles and which causes abnormal fatigability and even permanent muscle weakness. Ragged-red fibers and atrophy are found on muscle biopsy. A large proportion of chronic ophthalmoplegias are associated with other symptoms, leading to a multisystemic pattern of this disease. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism.

Multifunctional cell surface receptor that binds VLDL and transports it into cells by endocytosis and therefore plays an important role in energy metabolism. Also binds to a wide range of other molecules including Reelin/RELN or apolipoprotein E/APOE-containing ligands as well as clusterin/CLU (PubMed:24381170, PubMed:30873003). In the off-state of the pathway, forms homooligomers or heterooligomers with LRP8 (PubMed:30873003). Upon binding to ligands, homooligomers are rearranged to higher orde

Cell membraneMembrane, clathrin-coated pit

Cerebellar ataxia, impaired intellectual development, and dysequilibrium syndrome 1

An autosomal recessive, congenital, non-progressive cerebellar ataxia associated with disturbed equilibrium, delayed ambulation, intellectual disability, cerebellar hypoplasia and mild cerebral gyral simplification. Additional features include short stature, strabismus, pes planus and, rarely, seizures.

Processively dephosphorylates 'Ser-2' and 'Ser-5' of the heptad repeats YSPTSPS in the C-terminal domain of the largest RNA polymerase II subunit. This promotes the activity of RNA polymerase II. Plays a role in the exit from mitosis by dephosphorylating crucial mitotic substrates (USP44, CDC20 and WEE1) that are required for M-phase-promoting factor (MPF)/CDK1 inactivation

NucleusCytoplasm, cytoskeleton, microtubule organizing center, centrosomeCytoplasm, cytoskeleton, spindle poleMidbody

Congenital cataracts, facial dysmorphism, and neuropathy

An autosomal recessive developmental disorder characterized by a complex clinical phenotype with seemingly unrelated features involving multiple organs and systems. Developmental abnormalities include congenital cataracts and microcorneae, hypomyelination of the peripheral nervous system, impaired physical growth, delayed early motor and intellectual development, facial dysmorphism and hypogonadism. Central nervous system involvement, with cerebral and spinal cord atrophy, may be the result of disrupted development with superimposed degenerative changes. Affected individuals are prone to severe rhabdomyolysis after viral infections and to serious complications related to general anesthesia (such as pulmonary edema and epileptic seizures).

Required for protein translocation and folding in the endoplasmic reticulum (ER). Functions as a nucleotide exchange factor for the ER lumenal chaperone HSPA5

Endoplasmic reticulum lumen

Marinesco-Sjoegren syndrome

Autosomal recessive multisystem disorder which is characterized by cerebellar ataxia due to cerebellar atrophy, with Purkinje and granule cell loss and myopathy featuring marked muscle replacement with fat and connective tissue. Other cardinal features include bilateral cataracts, hypergonadotrophic hypogonadism and mild to severe intellectual disability. Skeletal abnormalities, short stature, dysarthria, strabismus and nystagmus are also frequent findings. Mutational inactivation of this protein may result in ER stress-induced cell death signaling or malfunctioning chaperone machineries that mishandle client proteins which are critical for the organs targeted in MSS.

May be involved in the trafficking and exocytosis of secretory vesicles in non-neuronal tissues. Is Ca(2+)-independent

Membrane

Spinocerebellar ataxia, autosomal recessive, 11

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR11 is associated with psychomotor retardation.

Tubulin is the major constituent of microtubules, a cylinder consisting of laterally associated linear protofilaments composed of alpha- and beta-tubulin heterodimers (PubMed:23001566, PubMed:26732629, PubMed:28013290). Microtubules grow by the addition of GTP-tubulin dimers to the microtubule end, where a stabilizing cap forms. Below the cap, tubulin dimers are in GDP-bound state, owing to GTPase activity of alpha-tubulin. Plays a critical role in proper axon guidance in both central and periph

Cytoplasm, cytoskeleton

Cortical dysplasia, complex, with other brain malformations 7

A malformation of the cortex in which the brain surface is irregular and characterized by an excessive number of small gyri with abnormal lamination. Polymicrogyria is a heterogeneous disorder, considered to be the result of postmigratory abnormal cortical organization.

Transcription factor that can both act as an activator or a repressor depending on the context. Plays a central role in BMP signaling and olfactory neurogenesis. Associates with SMADs in response to BMP2 leading to activate transcription of BMP target genes. Acts as a transcriptional repressor via its interaction with EBF1, a transcription factor involved in terminal olfactory receptor neurons differentiation; this interaction preventing EBF1 to bind DNA and activate olfactory-specific genes. In

Nucleus

Nephronophthisis 14

An autosomal recessive disorder manifesting as infantile-onset kidney disease, cerebellar vermis hypoplasia, and situs inversus. Nephronophthisis is a progressive tubulo-interstitial kidney disorder histologically characterized by modifications of the tubules with thickening of the basement membrane, interstitial fibrosis and, in the advanced stages, medullary cysts.

Metalloendopeptidase of the mitochondrial matrix that functions in peptide cleavage and degradation rather than in protein processing (PubMed:10360838, PubMed:16849325, PubMed:19196155, PubMed:24931469). Has an ATP-independent activity (PubMed:16849325). Specifically cleaves peptides in the range of 5 to 65 residues (PubMed:19196155). Shows a preference for cleavage after small polar residues and before basic residues, but without any positional preference (PubMed:10360838, PubMed:19196155, PubM

MitochondrionMitochondrion matrix

Spinocerebellar ataxia, autosomal recessive, 30

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR30 is a progressive disease characterized by childhood-onset global developmental delay with variably impaired intellectual development, motor dysfunction, and cerebellar ataxia. Affected individuals may also have psychiatric abnormalities.

Lysosomal serine protease with tripeptidyl-peptidase I activity (PubMed:11054422, PubMed:19038966, PubMed:19038967). May act as a non-specific lysosomal peptidase which generates tripeptides from the breakdown products produced by lysosomal proteinases (PubMed:11054422, PubMed:19038966, PubMed:19038967). Requires substrates with an unsubstituted N-terminus (PubMed:19038966)

LysosomeMelanosome

Ceroid lipofuscinosis, neuronal, 2

A form of neuronal ceroid lipofuscinosis. Neuronal ceroid lipofuscinoses are progressive neurodegenerative, lysosomal storage diseases characterized by intracellular accumulation of autofluorescent liposomal material, and clinically by seizures, dementia, visual loss, and/or cerebral atrophy. The lipopigment pattern seen most often in CLN2 consists of curvilinear profiles.

Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. Plays a role in cell protection against oxidative stress by detoxifying peroxides (PubMed:17707404, PubMed:29438714, PubMed:33889951, PubMed:7733872). Acts synergistically with MAP3K13 to regulate the activation of NF-kappa-B in the cytosol (PubMed:12492477). Required for the maintenance of physical strength (By similarity)

MitochondrionCytoplasmEarly endosome

Spinocerebellar ataxia, autosomal recessive, 32

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR32 is characterized by the onset of gait ataxia in the second or third decades of life. Other classic features include upper limb ataxia, oculomotor signs, dysphagia, and dysarthria. Some patients may have hyper- or hypokinetic movement abnormalities. Brain imaging shows cerebellar atrophy. Atrophy can extend to the brainstem and medullary olives.

Regulates COPI-mediated retrograde protein traffic at the interface between the Golgi apparatus and the endoplasmic reticulum (PubMed:18556652). Involved in the maintenance of the Golgi apparatus morphology (PubMed:26581903) Acts as a transcriptional activator. It binds to three different types of GC-rich DNA binding sites (box-A, -B and -C) in the beta-polymerase promoter region. It also binds to the TERT promoter region

Cytoplasm, cytoskeleton, microtubule organizing center, centrosomeEndoplasmic reticulum-Golgi intermediate compartmentGolgi apparatus, cis-Golgi networkCytoplasmNucleus

Spinocerebellar ataxia, autosomal recessive, 21

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR21 is characterized by cerebellar atrophy and ataxia with onset in early childhood. Patients also manifest recurrent episodes of liver failure, hepatic fibrosis and a peripheral neuropathy.

Required during ciliogenesis for tubulin glutamylation in cilium. Probably acts by participating in the transport of TTLL6, a tubulin polyglutamylase, between the basal body and the cilium

Cytoplasm, cytoskeleton, microtubule organizing center, centrosomeCell projection, ciliumCytoplasm, cytoskeleton, cilium basal body

Joubert syndrome 15

An autosomal recessive disorder presenting with cerebellar ataxia, oculomotor apraxia, hypotonia, neonatal breathing abnormalities and psychomotor delay. Neuroradiologically, it is characterized by cerebellar vermian hypoplasia/aplasia, thickened and reoriented superior cerebellar peduncles, and an abnormally large interpeduncular fossa, giving the appearance of a molar tooth on transaxial slices (molar tooth sign). Additional variable features include retinal dystrophy, renal disease, liver fibrosis and polydactyly.

Does not exhibit calcium-activated chloride channel (CaCC) activity. Can inhibit the activity of ANO1

Cell membrane

Spinocerebellar ataxia, autosomal recessive, 10

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR10 is characterized by onset in the teenage or young adult years of gait and limb ataxia, dysarthria, and nystagmus associated with marked cerebellar atrophy on brain imaging.

Component of the PEX1-PEX6 AAA ATPase complex, a protein dislocase complex that mediates the ATP-dependent extraction of the PEX5 receptor from peroxisomal membranes, an essential step for PEX5 recycling (PubMed:16314507, PubMed:16854980, PubMed:21362118, PubMed:29884772). Specifically recognizes PEX5 monoubiquitinated at 'Cys-11', and pulls it out of the peroxisome lumen through the PEX2-PEX10-PEX12 retrotranslocation channel (PubMed:29884772). Extraction by the PEX1-PEX6 AAA ATPase complex is

Cytoplasm, cytosolPeroxisome membraneCell projection, cilium, photoreceptor outer segment

Peroxisome biogenesis disorder complementation group 4

A peroxisomal disorder arising from a failure of protein import into the peroxisomal membrane or matrix. The peroxisome biogenesis disorders (PBD group) are genetically heterogeneous with at least 14 distinct genetic groups as concluded from complementation studies. Include disorders are: Zellweger syndrome (ZWS), neonatal adrenoleukodystrophy (NALD), infantile Refsum disease (IRD), and classical rhizomelic chondrodysplasia punctata (RCDP). ZWS, NALD and IRD are distinct from RCDP and constitute a clinical continuum of overlapping phenotypes known as the Zellweger spectrum (PBD-ZSS).

Uniporter that mediates the transport of extracellular choline and ethanolamine into cells, thereby playing a key role in phospholipid biosynthesis (PubMed:37100056, PubMed:38693265, PubMed:38778100, PubMed:39306721). Choline and ethanolamine are the precursors of phosphatidylcholine and phosphatidylethanolamine, respectively, the two most abundant phospholipids (PubMed:38693265, PubMed:38778100). Transport is not coupled with proton transport and is exclusively driven by the choline (or ethanol

Cell membraneMitochondrion membrane

Retinopathy-sensory neuropathy syndrome

An autosomal recessive neurodegenerative syndrome beginning in infancy with areflexia and retinitis pigmentosa. Nyctalopia (night blindness) and peripheral visual field loss are usually evident during late childhood or teenage years, with subsequent progressive constriction of the visual fields and loss of central retinal function over time. A sensory ataxia caused by degeneration of the posterior columns of the spinal cord results in a loss of proprioceptive sensation that is clinically evident in the second decade of life and gradually progresses. Scoliosis, camptodactyly, achalasia, gastrointestinal dysmotility, and a sensory peripheral neuropathy are variable features of the disease. Affected individuals have no clinical or radiological evidence of cerebral or cerebellar involvement. Some patients have pain insensitivity and commonly manifest self-injury, ulcers and amputations.

Tubulin-folding protein; involved in the second step of the tubulin folding pathway and in the regulation of tubulin heterodimer dissociation. Required for correct organization of microtubule cytoskeleton and mitotic splindle, and maintenance of the neuronal microtubule network

CytoplasmCytoplasm, cytoskeleton

Hypoparathyroidism-retardation-dysmorphism syndrome

An autosomal recessive multisystem disorder characterized by hypoparathyroidism, intrauterine and postnatal growth retardation, psychomotor retardation, epilepsy, microcephaly, and facial dysmorphism.

Electroneutral Na(+) /H(+) antiporter that extrudes Na(+) in exchange for external protons driven by the inward sodium ion chemical gradient, protecting cells from acidification that occurs from metabolism (PubMed:11350981, PubMed:11532004, PubMed:14680478, PubMed:15035633, PubMed:15677483, PubMed:17073455, PubMed:17493937, PubMed:22020933, PubMed:27650500, PubMed:32130622, PubMed:7110335, PubMed:7603840). Exchanges intracellular H(+) ions for extracellular Na(+) in 1:1 stoichiometry (By similar

Cell membraneBasolateral cell membrane

Lichtenstein-Knorr syndrome

An autosomal recessive neurologic disorder characterized by progressive cerebellar ataxia and severe progressive sensorineural hearing loss.

Adds a GMP to the 5'-end of tRNA(His) after transcription and RNase P cleavage. This step is essential for proper recognition of the tRNA and for the fidelity of protein synthesis (Probable). Also functions as a guanyl-nucleotide exchange factor/GEF for the MFN1 and MFN2 mitofusins thereby regulating mitochondrial fusion (PubMed:25008184, PubMed:27307223). By regulating both mitochondrial dynamics and bioenergetic function, it contributes to cell survival following oxidative stress (PubMed:25008

CytoplasmMitochondrion outer membrane

Spinocerebellar ataxia, autosomal recessive, 28

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR28 patients manifest mild motor developmental delay, gait ataxia, and dysarthria. Some patients show mildly impaired intellectual development. Disease onset is in early childhood.

Required for ciliogenesis and sonic hedgehog/SHH signaling. Required for the centrosomal recruitment of RAB8A and for the targeting of centriole satellite proteins to centrosomes such as of PCM1. May play a role in early ciliogenesis in the disappearance of centriolar satellites that preceeds ciliary vesicle formation (PubMed:24421332). Involved in regulation of cell intracellular organization. Involved in regulation of cell polarity (By similarity). Required for asymmetrical localization of CEP

Cytoplasm, cytoskeleton, microtubule organizing center, centrosomePhotoreceptor inner segmentCytoplasm, cytoskeleton, microtubule organizing center, centrosome, centrioleCytoplasm, cytoskeleton, cilium basal body

Joubert syndrome 23

A mild form of Joubert syndrome, a disorder presenting with cerebellar ataxia, oculomotor apraxia, hypotonia, neonatal breathing abnormalities and psychomotor delay. Neuroradiologically, it is characterized by cerebellar vermian hypoplasia/aplasia, thickened and reoriented superior cerebellar peduncles, and an abnormally large interpeduncular fossa, giving the appearance of a molar tooth on transaxial slices (molar tooth sign). Additional variable features include retinal dystrophy, renal disease, liver fibrosis, and polydactyly.

E3 ubiquitin-protein ligase which targets misfolded chaperone substrates towards proteasomal degradation (PubMed:10330192, PubMed:11146632, PubMed:11557750, PubMed:23990462, PubMed:26265139). Plays a role in the maintenance of mitochondrial morphology and promotes mitophagic removal of dysfunctional mitochondria; thereby acts as a protector against apoptosis in response to cellular stress (By similarity). Negatively regulates vascular smooth muscle contraction, via degradation of the transcripti

CytoplasmNucleusMitochondrion

Spinocerebellar ataxia, autosomal recessive, 16

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR16 is characterized by truncal and limb ataxia resulting in gait instability. Additionally, patients may show dysarthria, nystagmus, spasticity of the lower limbs, and mild peripheral sensory neuropathy.

Co-chaperone which acts as a regulator of the Hsp70 chaperone machinery and may be involved in the processing of other ataxia-linked proteins

Cytoplasm

Spastic ataxia Charlevoix-Saguenay type

A neurodegenerative disease characterized by early-onset cerebellar ataxia, spasticity, retinal hypermyelination, pyramidal signs, and both axonal and demyelinating neuropathy with loss of sensory nerve conduction and reduced motor conduction velocities. Other features include dysarthria, distal muscle wasting, nystagmus, defect in conjugate pursuit ocular movements, retinal striation (from prominent retinal nerves) obscuring the retinal blood vessels in places, and the frequent presence of mitral valve prolapse.

ATP-dependent 5'->3' DNA/RNA helicase that preferentially unwinds RNA substrates over DNA, playing a crucial role in resolving R-loops and promoting transcription termination (PubMed:36864660). Plays a role in transcription regulation by its ability to modulate RNA Polymerase II (Pol II) binding to chromatin and through its interaction with proteins involved in transcription (PubMed:19515850, PubMed:21700224). Contributes to the mRNA splicing efficiency and splice site selection (PubMed:19515850

NucleusNucleus, nucleoplasmNucleus, nucleolusCytoplasmChromosomeChromosome, telomereCell projection, axonCell projection, growth cone

Spinocerebellar ataxia, autosomal recessive, with axonal neuropathy 2

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAN2 is an autosomal recessive form associated with peripheral neuropathy and elevated serum alpha-fetoprotein, immunoglobulins and, less commonly, creatine kinase levels. Some SCAN2 patients manifest oculomotor apraxia.

Cytochrome P450 monooxygenase that catalyzes regio- and stereospecific hydroxylation of cholesterol and its derivatives. Hydroxylates (with R stereochemistry) the terminal methyl group of cholesterol side-chain in a three step reaction to yield at first a C26 alcohol, then a C26 aldehyde and finally a C26 acid (PubMed:12077124, PubMed:21411718, PubMed:28190002, PubMed:9660774). Regulates cholesterol homeostasis by catalyzing the conversion of excess cholesterol to bile acids via both the 'neutra

Mitochondrion inner membrane

Cerebrotendinous xanthomatosis

Rare sterol storage disorder characterized clinically by progressive neurologic dysfunction, premature atherosclerosis, and cataracts.

Plays a role in vesicle-mediated protein trafficking to lysosomal compartments including the endocytic membrane transport and autophagic pathways. Acts as a component of the HOPS endosomal tethering complex. This complex is proposed to be involved in the Rab5-to-Rab7 endosome conversion probably implicating MON1A/B, and via binding SNAREs and SNARE complexes to mediate tethering and docking events during SNARE-mediated membrane fusion. The HOPS complex is proposed to be recruited to Rab7 on the

Endosome membraneLate endosome membraneEarly endosome membraneLysosome membraneGolgi apparatus, trans-Golgi networkCytoplasmic vesicle, clathrin-coated vesicleCytoplasm, cytosol

Spinocerebellar ataxia, autosomal recessive, 29

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR29 is a progressive disease characterized by delayed motor development in early infancy followed by difficulty walking due to an ataxic gait or inability to walk, hypotonia, and variably impaired intellectual development.

Mitochondrial helicase involved in mtDNA replication and repair (PubMed:12975372, PubMed:15167897, PubMed:17324440, PubMed:18039713, PubMed:18971204, PubMed:25824949, PubMed:26887820, PubMed:27226550). Might have a role in mtDNA repair (PubMed:27226550). Has DNA strand separation activity needed to form a processive replication fork for leading strand synthesis which is catalyzed by the formation of a replisome complex with POLG and mtSDB (PubMed:12975372, PubMed:15167897, PubMed:18039713, PubMe

Mitochondrion matrix, mitochondrion nucleoidMitochondrion inner membrane

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant, 3

A disorder characterized by progressive weakness of ocular muscles and levator muscle of the upper eyelid. In a minority of cases, it is associated with skeletal myopathy, which predominantly involves axial or proximal muscles and which causes abnormal fatigability and even permanent muscle weakness. Ragged-red fibers and atrophy are found on muscle biopsy. A large proportion of chronic ophthalmoplegias are associated with other symptoms, leading to a multisystemic pattern of this disease. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism.

DNA repair enzyme that can remove a variety of covalent adducts from DNA through hydrolysis of a 5'-phosphodiester bond, giving rise to DNA with a free 5' phosphate. Catalyzes the hydrolysis of dead-end complexes between DNA and the topoisomerase 2 (TOP2) active site tyrosine residue. The 5'-tyrosyl DNA phosphodiesterase activity can enable the repair of TOP2-induced DNA double-strand breaks/DSBs without the need for nuclease activity, creating a 'clean' DSB with 5'-phosphate termini that are re

NucleusNucleus, PML bodyNucleus, nucleolusCytoplasm

Spinocerebellar ataxia, autosomal recessive, 23

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR23 patients manifest epilepsy, intellectual disability, and gait ataxia.

Member of the ionotropic glutamate receptor family, which plays a crucial role in synaptic organization and signal transduction in the central nervous system. Although it shares structural features with ionotropic glutamate receptors, does not bind glutamate as a primary ligand (PubMed:34936451). Promotes synaptogenesis and mediates the D-Serine-dependent long term depression signals and AMPA receptor endocytosis of cerebellar parallel fiber-Purkinje cell (PF-PC) synapses through the NRX1B-CBLN1

Postsynaptic cell membrane

Spinocerebellar ataxia, autosomal recessive, 18

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR18 features include progressive cerebellar atrophy, delayed psychomotor development, severely impaired gait, ocular movement abnormalities, and intellectual disability.

Atypical kinase involved in the biosynthesis of coenzyme Q, also named ubiquinone, an essential lipid-soluble electron transporter for aerobic cellular respiration (PubMed:21296186, PubMed:25498144, PubMed:25540914, PubMed:27499294, PubMed:36302899, PubMed:38425362). Its substrate specificity is still unclear: may act as a protein kinase that mediates phosphorylation of COQ3 (By similarity). According to other reports, acts as a small molecule kinase, possibly a lipid kinase that phosphorylates

Mitochondrion membrane

Coenzyme Q10 deficiency, primary, 4

An autosomal recessive disorder characterized by childhood-onset of cerebellar ataxia and exercise intolerance. Patient manifest gait ataxia and cerebellar atrophy with slow progression. Additional features include brisk tendon reflexes and Hoffmann sign, variable psychomotor retardation and variable seizures.

Involved in early and late steps in cilia formation. Its association with CCP110 is required for inhibition of primary cilia formation by CCP110 (PubMed:18694559). May play a role in early ciliogenesis in the disappearance of centriolar satellites and in the transition of primary ciliar vesicles (PCVs) to capped ciliary vesicles (CCVs). Required for the centrosomal recruitment of RAB8A and for the targeting of centriole satellite proteins to centrosomes such as of PCM1 (PubMed:24421332). Require

Cytoplasm, cytoskeleton, microtubule organizing center, centrosomeCytoplasm, cytoskeleton, microtubule organizing center, centrosome, centriolar satelliteNucleusCell projection, ciliumCytoplasm, cytoskeleton, cilium basal bodyCytoplasm, cytoskeleton, microtubule organizing center, centrosome, centrioleCytoplasmic vesicle

Joubert syndrome 5

A disorder presenting with cerebellar ataxia, oculomotor apraxia, hypotonia, neonatal breathing abnormalities and psychomotor delay. Neuroradiologically, it is characterized by cerebellar vermian hypoplasia/aplasia, thickened and reoriented superior cerebellar peduncles, and an abnormally large interpeduncular fossa, giving the appearance of a molar tooth on transaxial slices (molar tooth sign). Additional variable features include retinal dystrophy and renal disease. Joubert syndrome type 5 shares the neurologic and neuroradiologic features of Joubert syndrome together with severe retinal dystrophy and/or progressive renal failure characterized by nephronophthisis.

Transmembrane component of the tectonic-like complex, a complex localized at the transition zone of primary cilia and acting as a barrier that prevents diffusion of transmembrane proteins between the cilia and plasma membranes. Required for ciliogenesis and sonic hedgehog/SHH signaling (By similarity)

Cell projection, cilium membrane

Joubert syndrome 20

A disorder presenting with cerebellar ataxia, oculomotor apraxia, hypotonia, neonatal breathing abnormalities and psychomotor delay. Neuroradiologically, it is characterized by cerebellar vermian hypoplasia/aplasia, thickened and reoriented superior cerebellar peduncles, and an abnormally large interpeduncular fossa, giving the appearance of a molar tooth on transaxial slices (molar tooth sign). Additional variable features include retinal dystrophy and renal disease.

Functions as a negative regulator of the PI3 kinase/PI3K activity associated with endosomal membranes via BECN1, a core subunit of the PI3K complex. By modifying the phosphatidylinositol 3-phosphate/PtdInsP3 content of endosomal membranes may regulate endosome fusion, recycling, sorting and early to late endosome transport (PubMed:26783301). It is for instance, required for the delivery of cargos like BST2/tetherin from early to late endosome and thereby participates indirectly to their degradat

Early endosome membraneLate endosome membraneLysosome membraneCytoplasmic vesicle, autophagosome membraneMitochondrionCytoplasm, cytosol

Cerebellar ataxia, impaired intellectual development, and dysequilibrium syndrome 2

An autosomal recessive, congenital cerebellar ataxia associated with cerebellar hypoplasia, intellectual disability, and inability to walk bipedally, resulting in quadrupedal locomotion as a functional adaptation. Additional findings include generalized brain atrophy and mild hypoplasia of the corpus callosum.

Multi-isomeric modular protein which forms a linking network between organelles and the actin cytoskeleton to maintain the subcellular spatial organization. As a component of the LINC (LInker of Nucleoskeleton and Cytoskeleton) complex involved in the connection between the nuclear lamina and the cytoskeleton. The nucleocytoplasmic interactions established by the LINC complex play an important role in the transmission of mechanical forces across the nuclear envelope and in nuclear movement and p

Nucleus outer membraneNucleusNucleus envelopeCytoplasm, cytoskeletonCytoplasm, myofibril, sarcomereGolgi apparatus

Spinocerebellar ataxia, autosomal recessive, 8

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR8 is an autosomal recessive form.

E1-like activating enzyme involved in the 2 ubiquitin-like systems required for cytoplasm to vacuole transport (Cvt) and autophagy. Activates ATG12 for its conjugation with ATG5 as well as the ATG8 family proteins for their conjugation with phosphatidylethanolamine. Both systems are needed for the ATG8 association to Cvt vesicles and autophagosomes membranes. Required for autophagic death induced by caspase-8 inhibition. Facilitates LC3-I lipidation with phosphatidylethanolamine to form LC3-II w

CytoplasmPreautophagosomal structure

Spinocerebellar ataxia, autosomal recessive, 31

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR30 is characterized by global developmental delay, hypotonia, variably impaired intellectual and language development, ataxic gait, tremor, and dysarthria. Most affected individuals have optic atrophy. Additional features may include retinitis pigmentosa, sensorineural deafness, dysmorphic facial features, and possibly endocrine dysfunction.

Spinocerebellar ataxia, autosomal recessive, 27

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR27 is a progressive disease characterized by gait difficulties, eye movement abnormalities, dysarthria, and difficulty writing. Some patients may lose independent ambulation. Additional features include spasticity of the lower limbs and cognitive impairment.

Putative oxidoreductase. Acts as a tumor suppressor and plays a role in apoptosis. Required for normal bone development (By similarity). May function synergistically with p53/TP53 to control genotoxic stress-induced cell death. Plays a role in TGFB1 signaling and TGFB1-mediated cell death. May also play a role in tumor necrosis factor (TNF)-mediated cell death. Inhibits Wnt signaling, probably by sequestering DVL2 in the cytoplasm

CytoplasmNucleusMitochondrionGolgi apparatusLysosome

Component of the tectonic-like complex, a complex localized at the transition zone of primary cilia and acting as a barrier that prevents diffusion of transmembrane proteins between the cilia and plasma membranes. Involved in centrosome migration to the apical cell surface during early ciliogenesis. Required for ciliary structure and function, including a role in regulating length and appropriate number through modulating centrosome duplication. Required for cell branching morphology

Cytoplasm, cytoskeleton, cilium basal bodyCytoplasm, cytoskeleton, microtubule organizing center, centrosome

Meckel syndrome 1

A disorder characterized by a combination of renal cysts and variably associated features including developmental anomalies of the central nervous system (typically encephalocele), hepatic ductal dysplasia and cysts, and polydactyly.

Functions as an activator of persulfide transfer to the scaffoding protein ISCU as component of the core iron-sulfur cluster (ISC) assembly complex and participates to the [2Fe-2S] cluster assembly (PubMed:12785837, PubMed:24971490). Accelerates sulfur transfer from NFS1 persulfide intermediate to ISCU and to small thiols such as L-cysteine and glutathione leading to persulfuration of these thiols and ultimately sulfide release (PubMed:24971490). Binds ferrous ion and is released from FXN upon t

MitochondrionCytoplasm, cytosol

Friedreich ataxia

Autosomal recessive, progressive degenerative disease characterized by neurodegeneration and cardiomyopathy it is the most common inherited ataxia. The disorder is usually manifest before adolescence and is generally characterized by incoordination of limb movements, dysarthria, nystagmus, diminished or absent tendon reflexes, Babinski sign, impairment of position and vibratory senses, scoliosis, pes cavus, and hammer toe. In most patients, FRDA is due to GAA triplet repeat expansions in the first intron of the frataxin gene. But in some cases the disease is due to mutations in the coding region.

Regulatory subunit of the PI3K gamma complex. Required for recruitment of the catalytic subunit to the plasma membrane via interaction with beta-gamma G protein dimers. Required for G protein-mediated activation of PIK3CG (By similarity)

NucleusCytoplasmCell membrane

Ataxia-oculomotor apraxia 3

An autosomal recessive disease characterized by cerebellar ataxia, oculomotor apraxia, areflexia and peripheral neuropathy.

E1-like enzyme which specifically catalyzes the first step in ufmylation (PubMed:15071506, PubMed:18442052, PubMed:20368332, PubMed:25219498, PubMed:26929408, PubMed:27545674, PubMed:27545681, PubMed:27653677, PubMed:30412706, PubMed:30626644, PubMed:34588452). Activates UFM1 by first adenylating its C-terminal glycine residue with ATP, and thereafter linking this residue to the side chain of a cysteine residue in E1, yielding a UFM1-E1 thioester and free AMP (PubMed:20368332, PubMed:26929408, P

CytoplasmNucleusEndoplasmic reticulum membraneGolgi apparatus

Developmental and epileptic encephalopathy 44

A form of epileptic encephalopathy, a heterogeneous group of severe early-onset epilepsies characterized by refractory seizures, neurodevelopmental impairment, and poor prognosis. Development is normal prior to seizure onset, after which cognitive and motor delays become apparent. DEE44 transmission pattern is consistent with autosomal recessive inheritance.

Component of the tectonic-like complex, a complex localized at the transition zone of primary cilia and acting as a barrier that prevents diffusion of transmembrane proteins between the cilia and plasma membranes. Required for ciliogenesis and sonic hedgehog/SHH signaling (By similarity)

CytoplasmCytoplasm, cytoskeleton, cilium basal body

Meckel syndrome 6

A disorder characterized by a combination of renal cysts and variably associated features including developmental anomalies of the central nervous system (typically encephalocele), hepatic ductal dysplasia and cysts, and polydactyly.

Negatively regulates signaling through the G-protein coupled thromboxane A2 receptor (TBXA2R) (PubMed:19464661). May be involved in mechanisms like programmed cell death, craniofacial development, patterning of the limbs, and formation of the left-right axis (By similarity). Involved in the organization of apical junctions; the function is proposed to implicate a NPHP1-4-8 module. Does not seem to be strictly required for ciliogenesis (PubMed:19464661). Involved in establishment of planar cell p

CytoplasmCytoplasm, cytoskeleton, cilium basal bodyCytoplasm, cytoskeleton, cilium axonemeCytoplasm, cytoskeleton, microtubule organizing center, centrosomeCell junction, tight junction

Scaffold protein involved in DNA single-strand break repair by mediating the assembly of DNA break repair protein complexes (PubMed:11163244, PubMed:28002403). Negatively regulates ADP-ribosyltransferase activity of PARP1 during base-excision repair in order to prevent excessive PARP1 activity (PubMed:28002403, PubMed:34102106, PubMed:34811483). Recognizes and binds poly-ADP-ribose chains: specifically binds auto-poly-ADP-ribosylated PARP1, limiting its activity (PubMed:14500814, PubMed:34102106

NucleusChromosome

Spinocerebellar ataxia, autosomal recessive, 26

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR26 is a progressive disease characterized by gait and limb ataxia, loss of independent ambulation, oculomotor apraxia, and peripheral neuropathy with distal muscle weakness and areflexia.

E3 ubiquitin-protein ligase component of a retrotranslocation channel required for peroxisome organization by mediating export of the PEX5 receptor from peroxisomes to the cytosol, thereby promoting PEX5 recycling (PubMed:24662292). The retrotranslocation channel is composed of PEX2, PEX10 and PEX12; each subunit contributing transmembrane segments that coassemble into an open channel that specifically allows the passage of PEX5 through the peroxisomal membrane (By similarity). PEX10 also regula

Peroxisome membrane

Peroxisome biogenesis disorder complementation group 7

A peroxisomal disorder arising from a failure of protein import into the peroxisomal membrane or matrix. The peroxisome biogenesis disorders (PBD group) are genetically heterogeneous with at least 14 distinct genetic groups as concluded from complementation studies. Include disorders are: Zellweger syndrome (ZWS), neonatal adrenoleukodystrophy (NALD), infantile Refsum disease (IRD), and classical rhizomelic chondrodysplasia punctata (RCDP). ZWS, NALD and IRD are distinct from RCDP and constitute a clinical continuum of overlapping phenotypes known as the Zellweger spectrum (PBD-ZSS).

Required for ciliary structure and function. Part of the tectonic-like complex which is required for tissue-specific ciliogenesis and may regulate ciliary membrane composition (By similarity). Involved in centrosome migration to the apical cell surface during early ciliogenesis. Involved in the regulation of cilia length and appropriate number through the control of centrosome duplication. Is a key regulator of stereociliary bundle orientation (By similarity). Required for epithelial cell branch

Cell membraneEndoplasmic reticulum membraneCell projection, ciliumCytoplasm, cytoskeleton, cilium basal body

Subunit of the replication factor C (RFC) complex which acts during elongation of primed DNA templates by DNA polymerases delta and epsilon, and is necessary for ATP-dependent loading of proliferating cell nuclear antigen (PCNA) onto primed DNA (PubMed:9488738). This subunit binds to the primer-template junction. Binds the PO-B transcription element as well as other GA rich DNA sequences. Can bind single- or double-stranded DNA

Nucleus

Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome

An autosomal recessive neurologic disease characterized by imbalance, cerebellar ataxia, impaired vestibular function, and non-length-dependent sensory deficit.

Plays a key role in the repair of DNA damage, functioning as part of both the non-homologous end-joining (NHEJ) and base excision repair (BER) pathways (PubMed:10446192, PubMed:10446193, PubMed:15385968, PubMed:20852255, PubMed:28453785). Through its two catalytic activities, PNK ensures that DNA termini are compatible with extension and ligation by either removing 3'-phosphates from, or by phosphorylating 5'-hydroxyl groups on, the ribose sugar of the DNA backbone (PubMed:10446192, PubMed:10446

NucleusChromosome

Microcephaly, seizures, and developmental delay

An autosomal recessive neurodevelopmental disorder characterized by infantile-onset seizures, microcephaly, severe intellectual disability and delayed motor milestones with absent speech or only achieving a few words. Most patients also have behavioral problems with hyperactivity. Microcephaly is progressive and without neuronal migration or structural abnormalities, consistent with primary microcephaly.

Does not have a carbonic anhydrase catalytic activity

Spinocerebellar ataxia, autosomal recessive, 34

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR34 is characterized by congenital cerebellar ataxia associated with dysarthia, quadrupedal gait and intellectual disability.

May play a role in cell-cycle-dependent microtubule organization

Cytoplasm, cytoskeleton, microtubule organizing center, centrosomeCytoplasm, cytoskeleton, spindleCytoplasm, cytoskeleton, spindle poleCell projection, cilium

Joubert syndrome 21

A disorder presenting with cerebellar ataxia, oculomotor apraxia, hypotonia, neonatal breathing abnormalities and psychomotor delay. Neuroradiologically, it is characterized by cerebellar vermian hypoplasia/aplasia, thickened and reoriented superior cerebellar peduncles, and an abnormally large interpeduncular fossa, giving the appearance of a molar tooth on transaxial slices (molar tooth sign). Additional variable features include retinal dystrophy, renal disease, liver fibrosis, and polydactyly.

Component of the transition zone in primary cilia. Required for ciliogenesis

MembraneCell projection, cilium

Joubert syndrome 14

An autosomal recessive disorder characterized by severe intellectual disability, hypotonia, breathing abnormalities in infancy, and dysmorphic facial features. Neuroradiologically, it is characterized by cerebellar vermian hypoplasia/aplasia, thickened and reoriented superior cerebellar peduncles, and an abnormally large interpeduncular fossa, giving the appearance of a molar tooth on transaxial slices (molar tooth sign). Additional variable features include renal disease, abnormal eye movements, and postaxial polydactyly.

E3 ubiquitin-protein ligase required for accumulation of repair proteins to sites of DNA damage. Acts with UBE2N/UBC13 to amplify the RNF8-dependent histone ubiquitination. Recruited to sites of DNA damage at double-strand breaks (DSBs) by binding to ubiquitinated histone H2A and H2AX and amplifies the RNF8-dependent H2A ubiquitination, promoting the formation of 'Lys-63'-linked ubiquitin conjugates. This leads to concentrate ubiquitinated histones H2A and H2AX at DNA lesions to the threshold re

Nucleus

Riddle syndrome

An autosomal recessive disorder characterized by increased radiosensitivity, immunodeficiency, mild motor control and learning difficulties, facial dysmorphism, and short stature.

DNA repair enzyme that can remove a variety of covalent adducts from DNA through hydrolysis of a 3'-phosphodiester bond, giving rise to DNA with a free 3' phosphate. Catalyzes the hydrolysis of dead-end complexes between DNA and the topoisomerase I active site tyrosine residue. Hydrolyzes 3'-phosphoglycolates on protruding 3' ends on DNA double-strand breaks due to DNA damage by radiation and free radicals. Acts on blunt-ended double-strand DNA breaks and on single-stranded DNA. Has low 3'exonuc

NucleusCytoplasm

Spinocerebellar ataxia, autosomal recessive, with axonal neuropathy 1

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAN1 is an autosomal recessive cerebellar ataxia (ARCA) associated with peripheral axonal motor and sensory neuropathy, distal muscular atrophy, pes cavus and steppage gait as seen in Charcot-Marie-Tooth neuropathy. All affected individuals have normal intelligence.

Essential for primary ciliogenesis and embryonic development, facilitating the activation of Hedgehog (Hh) signaling pathway. Disrupts the interaction of GLI2 and GLI3 with the negative regulator SUFU. Inhibiting SUFU's interaction with GLI2 promotes the entry of GLI2 into the nucleus, allowing it to activate Hh target gene expression. Disrupting SUFU's interaction with GLI3 prevents its conversion into the repressor form, leading to increased nuclear GLI3 and enhanced Hh signaling. Required for

MembraneCytoplasm, cytoskeleton, cilium basal body

Joubert syndrome 2

A disorder presenting with cerebellar ataxia, oculomotor apraxia, hypotonia, neonatal breathing abnormalities and psychomotor delay. Neuroradiologically, it is characterized by cerebellar vermian hypoplasia/aplasia, thickened and reoriented superior cerebellar peduncles, and an abnormally large interpeduncular fossa, giving the appearance of a molar tooth on transaxial slices (molar tooth sign). Additional variable features include retinal dystrophy and renal disease.

Spinocerebellar ataxia, autosomal recessive, 17

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR17 features include non-progressive congenital cerebellar ataxia, mildly delayed walking with an unsteady gait and frequent falls, dysarthria, dysmetria, hypotonia in the extremities, truncal ataxia, increased reflexes in the lower extremities, and intellectual disability.

Inhibits PIK3C3 activity; under basal conditions negatively regulates PI3K complex II (PI3KC3-C2) function in autophagy. Negatively regulates endosome maturation and degradative endocytic trafficking and impairs autophagosome maturation process. Can sequester UVRAG from association with a class C Vps complex (possibly the HOPS complex) and negatively regulates Rab7 activation (PubMed:20974968, PubMed:21062745) Involved in regulation of pathogen-specific host defense of activated macrophages. Fol

Late endosomeLysosomeEarly endosome

Spinocerebellar ataxia, autosomal recessive, 15

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR15 patients manifest cerebellar ataxia in early childhood and delayed motor development with delayed walking. Additional features include dysarthria, upper limb involvement, abnormal eye movements, and hyporeflexia.

Probably plays an important role in neuronal membrane skeleton

Cytoplasm, cytoskeletonCytoplasm, cell cortex

Spinocerebellar ataxia 5

Spinocerebellar ataxia is a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCA5 is an autosomal dominant cerebellar ataxia (ADCA). It is a slowly progressive disorder with variable age at onset, ranging between 10 and 50 years.

Plays a role in maintaining normal neuronal excitability and synaptic transmission. May be involved in several stages of intracellular trafficking (By similarity). Required for autophagosome clearance, possibly by mediating the fusion of lysosomes with autophagosomes (Probable). Binds phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2), a key component of late endosomes/lysosomes (PubMed:25848753). Does not bind phosphatidylinositol 3-phosphate (PtdIns(3P)) (PubMed:25148684, PubMed:25848753)

Lysosome membraneLate endosome membraneCell projection, dendrite

Spinocerebellar ataxia, autosomal recessive, 20

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR20 is characterized by cerebellar atrophy, ataxia, coarsened facial features, severely delayed psychomotor development with poor or absent speech, and intellectual disability.

Catalytic component of a P4-ATPase flippase complex which catalyzes the hydrolysis of ATP coupled to the transport of aminophospholipids from the outer to the inner leaflet of various membranes and ensures the maintenance of asymmetric distribution of phospholipids (By similarity). Able to translocate phosphatidylserine, but not phosphatidylcholine (PubMed:34403372). Phospholipid translocation also seems to be implicated in vesicle formation and in uptake of lipid signaling molecules (By similar

MembraneGolgi apparatus membraneEndosome membraneCell membranePhotoreceptor outer segment membranePhotoreceptor inner segment membrane

Cerebellar ataxia, impaired intellectual development, and dysequilibrium syndrome 4

An autosomal recessive, congenital cerebellar ataxia associated with dysarthia, quadrupedal gait and intellectual disability.

Required for assembly of mitochondrial respiratory chain complex I and complex IV

Mitochondrion intermembrane space

Spinocerebellar ataxia, autosomal recessive, with axonal neuropathy 3

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAN3 is an autosomal recessive disorder characterized by onset in the first decade of slowly progressive distal muscle weakness and atrophy and distal sensory impairment due to an axonal peripheral neuropathy. Affected individuals have gait disturbances and sometimes manual dexterity difficulties, as well as cerebellar ataxia associated with cerebellar atrophy on brain imaging.

Catalyzes the transport of triglyceride, cholesteryl ester, and phospholipid between phospholipid surfaces (PubMed:15897609, PubMed:16478722, PubMed:22236406, PubMed:23475612, PubMed:25108285, PubMed:26224785, PubMed:8876250, PubMed:8939939). Required for the assembly and secretion of plasma lipoproteins that contain apolipoprotein B (PubMed:16478722, PubMed:23475612, PubMed:26224785, PubMed:8876250, PubMed:8939939). May be involved in regulating cholesteryl ester biosynthesis in cells that prod

Endoplasmic reticulumGolgi apparatus

Abetalipoproteinemia

An autosomal recessive disorder of lipoprotein metabolism. Affected individuals produce virtually no circulating apolipoprotein B-containing lipoproteins (chylomicrons, VLDL, LDL, lipoprotein(A)). Malabsorption of the antioxidant vitamin E occurs, leading to spinocerebellar and retinal degeneration.

Required for ciliogenesis

Vacuole membraneCell projection, cilium

Joubert syndrome 16

An autosomal recessive disorder characterized by oculomotor apraxia, variable coloboma, and rare kidney involvement. Neuroradiologically, it is characterized by an abnormally large interpeduncular fossa, giving the appearance of a molar tooth on transaxial slices (molar tooth sign). Additional variable features include retinal dystrophy and polydactyly.

Substrate recognition and binding subunit of the essential mitochondrial processing protease (MPP), which cleaves the mitochondrial sequence off newly imported precursors proteins

Mitochondrion matrixMitochondrion inner membrane

Spinocerebellar ataxia, autosomal recessive, 2

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR2 is characterized by onset of impaired motor development and ataxic gait in early childhood. Additional features often include loss of fine motor skills, dysarthria, nystagmus, cerebellar signs, and delayed cognitive development with intellectual disability.

Functions in the development of neural tissues, particularly the postnatal maturation of the cerebellar cortex. May play a role in neurotransmission through regulation of glutaminase/GLS, an enzyme responsible for the production in neurons of the glutamate neurotransmitter. Alternatively, may regulate the localization of mitochondria within axons and dendrites

Cell projection, axonCell projection, dendritePresynapseMitochondrionCell projection, growth coneCytoplasm

Cerebellar ataxia, cayman type

Found in a population isolate on Grand Cayman Island and causes a marked psychomotor retardation and prominent nonprogressive cerebellar dysfunction including nystagmus, intention tremor, dysarthria, and wide-based ataxic gait. Hypotonia is present from early childhood.

G-protein coupled receptor for glutamate. Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of down-stream effectors. Signaling activates a phosphatidylinositol-calcium second messenger system. May participate in the central action of glutamate in the CNS, such as long-term potentiation in the hippocampus and long-term depression in the cerebellum (PubMed:24603153, PubMed:28886343, PubMed:7476890).

Cell membranePostsynaptic cell membraneCell projection, dendrite

Spinocerebellar ataxia, autosomal recessive, 13

A form of spinocerebellar ataxia, a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR13 is characterized by delayed psychomotor development beginning in infancy. Affected individuals show mild to profound intellectual disability with poor or absent speech as well as gait and stance ataxia and hyperreflexia.

Involved in vesicle trafficking and required for ciliogenesis, formation of primary non-motile cilium, and recruitment of RAB8A to the basal body of primary cilium. Component of the tectonic-like complex, a complex localized at the transition zone of primary cilia and acting as a barrier that prevents diffusion of transmembrane proteins between the cilia and plasma membranes. Involved in neuronal differentiation. As a positive modulator of classical Wnt signaling, may play a crucial role in cili

Cytoplasm, cytoskeleton, cilium basal bodyCell junction, adherens junctionCytoplasm, cytoskeleton, microtubule organizing center, centrosome, centriole

Joubert syndrome 3

A disorder presenting with cerebellar ataxia, oculomotor apraxia, hypotonia, neonatal breathing abnormalities and psychomotor delay. Neuroradiologically, it is characterized by cerebellar vermian hypoplasia/aplasia, thickened and reoriented superior cerebellar peduncles, and an abnormally large interpeduncular fossa, giving the appearance of a molar tooth on transaxial slices (molar tooth sign). Additional variable features include retinal dystrophy and renal disease. Joubert syndrome type 3 shows minimal extra central nervous system involvement and appears not to be associated with renal dysfunction.