Fumarase deficiency

A severe autosomal recessive metabolic disorder characterized by early-onset hypotonia, profound psychomotor retardation, and brain abnormalities, such as agenesis of the corpus callosum, gyral defects, and ventriculomegaly. Many patients show neonatal distress, metabolic acidosis, and/or encephalopathy.

Mitochondrial complex V deficiency, mitochondrial 2

A mitochondrial disorder with heterogeneous clinical manifestations including neuropathy, ataxia, hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy can present with negligible to extreme hypertrophy, minimal to extensive fibrosis and myocyte disarray, absent to severe left ventricular outflow tract obstruction, and distinct septal contours/morphologies with extremely varying clinical course.

Glutaric aciduria 2C

An autosomal recessively inherited disorder of fatty acid, amino acid, and choline metabolism. It is characterized by multiple acyl-CoA dehydrogenase deficiencies resulting in large excretion not only of glutaric acid, but also of lactic, ethylmalonic, butyric, isobutyric, 2-methyl-butyric, and isovaleric acids.

Glutaric aciduria 2A

An autosomal recessively inherited disorder of fatty acid, amino acid, and choline metabolism. It is characterized by multiple acyl-CoA dehydrogenase deficiencies resulting in large excretion not only of glutaric acid, but also of lactic, ethylmalonic, butyric, isobutyric, 2-methyl-butyric, and isovaleric acids.

Mitochondrial complex IV deficiency, nuclear type 5

An autosomal recessive, severe mitochondrial disease with multisystemic manifestations and early onset. Clinical features include delayed psychomotor development, impaired intellectual development with speech delay, mild dysmorphic facial features, hypotonia, ataxia, and seizures. Brain imaging shows bilaterally symmetrical necrotic lesions in subcortical brain regions. Mortality is high, due to episodes of severe metabolic acidosis and coma.

Mitochondrial complex I deficiency, nuclear type 25

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN25 transmission pattern is consistent with autosomal recessive inheritance.

Mitochondrial complex I deficiency, nuclear type 7

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN7 transmission pattern is consistent with autosomal recessive inheritance.

Dystonia, childhood-onset, with optic atrophy and basal ganglia abnormalities

An autosomal recessive neurologic disorder characterized by childhood-onset dystonia, basal ganglia degeneration and optic atrophy with decreased visual acuity. Dystonia is defined by the presence of sustained involuntary muscle contraction, often leading to abnormal postures. DYTOABG severity is variable, and some patients lose independent ambulation.

D-bifunctional protein deficiency

Disorder of peroxisomal fatty acid beta-oxidation.

Combined oxidative phosphorylation deficiency 6

A mitochondrial disease resulting in a neurodegenerative disorder characterized by psychomotor delay, hypotonia, areflexia, muscle weakness and wasting. Some patients manifest prenatal ventriculomegaly and severe postnatal encephalomyopathy.

Leber hereditary optic neuropathy

A maternally inherited form of Leber hereditary optic neuropathy, a mitochondrial disease resulting in bilateral painless loss of central vision due to selective degeneration of the retinal ganglion cells and their axons. The disorder shows incomplete penetrance and male predominance. Cardiac conduction defects and neurological defects have also been described in some LHON patients. LHON results from primary mitochondrial DNA mutations affecting the respiratory chain complexes.

Lipoyltransferase 1 deficiency

An autosomal recessive disorder due to a defect in lipoic acid metabolism, resulting in severe lactic acidosis and metabolic decompensation. Variable clinical manifestations include delayed psychomotor development, severe hypotonia, dystonia, loss of head control, coma, bradycardia, and pulmonary hypertension.

Immunodeficiency 115 with autoinflammation

An autosomal recessive immunologic disorder manifesting in early infancy and characterized by combined immunodeficiency, recurrent bacterial, viral, and fungal infections, as well as autoinflammatory features, including arthritis and dermatitis.

Mitochondrial DNA depletion syndrome 1, MNGIE type

A multisystem disease associated with mitochondrial dysfunction. It is clinically characterized by onset between the second and fifth decades of life, ptosis, progressive external ophthalmoplegia, gastrointestinal dysmotility (often pseudoobstruction), diffuse leukoencephalopathy, cachexia, peripheral neuropathy, and myopathy.

Mitochondrial complex III deficiency, nuclear type 7

A form of mitochondrial complex III deficiency, a disorder of the mitochondrial respiratory chain resulting in a highly variable phenotype depending on which tissues are affected. MC3DN7 is characterized by severe intrauterine growth retardation, neonatal lactic acidosis and renal tubular dysfunction. Additional clinical features include a dysmorphic facial appearance, delayed psychomotor development, autistic features, aggressive behavior, and mild sensorineural hearing loss.

Mitochondrial complex III deficiency, nuclear type 5

A disorder of the mitochondrial respiratory chain resulting in a highly variable phenotype depending on which tissues are affected. Clinical features include mitochondrial encephalopathy, psychomotor retardation, ataxia, severe failure to thrive, liver dysfunction, renal tubulopathy, muscle weakness and exercise intolerance.

Adenosine monophosphate deaminase deficiency erythrocyte type

A metabolic disorder due to lack of activity of the erythrocyte isoform of AMP deaminase. It is a clinically asymptomatic condition characterized by a 50% increase in steady-state levels of ATP in affected cells. Individuals with complete deficiency of erythrocyte AMP deaminase are healthy and have no hematologic disorders.

Acyl-CoA dehydrogenase very long-chain deficiency

An inborn error of mitochondrial fatty acid beta-oxidation which leads to impaired long-chain fatty acid beta-oxidation. It is clinically heterogeneous, with three major phenotypes: a severe childhood form characterized by early onset, high mortality and high incidence of cardiomyopathy; a milder childhood form with later onset, characterized by hypoketotic hypoglycemia, low mortality and rare cardiomyopathy; an adult form, with isolated skeletal muscle involvement, rhabdomyolysis and myoglobinuria, usually triggered by exercise or fasting.

Pyruvate dehydrogenase E1-beta deficiency

An enzymatic defect causing primary lactic acidosis in children. It is associated with a broad clinical spectrum ranging from fatal lactic acidosis in the newborn to chronic neurologic dysfunction with structural abnormalities in the central nervous system without systemic acidosis.

Symptomatic deficiency in lactate transport

Deficiency of lactate transporter may result in an acidic intracellular environment created by muscle activity with consequent degeneration of muscle and release of myoglobin and creatine kinase. This defect might compromise extreme performance in otherwise healthy individuals.

Glycogen storage disease 1A

A metabolic disorder characterized by impairment of terminal steps of glycogenolysis and gluconeogenesis. Patients manifest a wide range of clinical symptoms and biochemical abnormalities, including hypoglycemia, severe hepatomegaly due to excessive accumulation of glycogen, kidney enlargement, growth retardation, lactic acidemia, hyperlipidemia, and hyperuricemia.

Mitochondrial DNA depletion syndrome 3

A disorder due to mitochondrial dysfunction characterized by onset in infancy of progressive liver failure, hypoglycemia, increased lactate in body fluids, and neurologic abnormalities including hypotonia, encephalopathy, peripheral neuropathy. Affected tissues show both decreased activity of the mtDNA-encoded respiratory chain complexes and mtDNA depletion.

Polyglucosan body myopathy 1 with or without immunodeficiency

A disease characterized by polyglucosan storage myopathy associated with early-onset progressive muscle weakness and progressive dilated cardiomyopathy, which may necessitate cardiac transplant in severe cases. Some patients present with severe immunodeficiency, invasive bacterial infections and chronic autoinflammation.

Neuropathy, ataxia, and retinitis pigmentosa

A syndrome characterized by variable combination of developmental delay, psychomotor retardation, hearing loss, optic atrophy and retinitis pigmentosa, dementia, seizures, ataxia, proximal neurogenic muscle weakness, and sensory neuropathy.

Leber hereditary optic neuropathy

A maternally inherited form of Leber hereditary optic neuropathy, a mitochondrial disease resulting in bilateral painless loss of central vision due to selective degeneration of the retinal ganglion cells and their axons. The disorder shows incomplete penetrance and male predominance. Cardiac conduction defects and neurological defects have also been described in some LHON patients. LHON results from primary mitochondrial DNA mutations affecting the respiratory chain complexes.

Leucine-induced hypoglycemia

Rare cause of hypoglycemia and is described as a condition in which symptomatic hypoglycemia is provoked by high protein feedings. Hypoglycemia is also elicited by administration of oral or intravenous infusions of a single amino acid, leucine.

Combined oxidative phosphorylation deficiency 40

An autosomal recessive mitochondrial disorder characterized by prenatal or infantile onset, fetal hydrops, severe hypertrophic cardiomyopathy, poor growth, sensorineural hearing loss, hepatic dysfunction, lactic acidosis, and decreased activities of mitochondrial respiratory complexes I, III, IV, and V. The disorder is lethal, with death occurring in infancy.

Combined oxidative phosphorylation deficiency 9

A mitochondrial disease characterized by failure to thrive, poor feeding, hypertrophic cardiomyopathy, hepatomegaly, and psychomotor retardation. Death in infancy has been observed in some cases.

Combined oxidative phosphorylation deficiency 8

A mitochondrial disease characterized by a lethal infantile hypertrophic cardiomyopathy, generalized muscle dysfunction and some neurologic involvement. The liver is not affected.

Leber hereditary optic neuropathy

A maternally inherited form of Leber hereditary optic neuropathy, a mitochondrial disease resulting in bilateral painless loss of central vision due to selective degeneration of the retinal ganglion cells and their axons. The disorder shows incomplete penetrance and male predominance. Cardiac conduction defects and neurological defects have also been described in some LHON patients. LHON results from primary mitochondrial DNA mutations affecting the respiratory chain complexes.

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant, 4

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.

Mitochondrial complex IV deficiency, nuclear type 11

An autosomal recessive mitochondrial disorder with onset in childhood or adolescence. MC4DN11 is characterized by walking difficulties, cerebellar ataxia, dystonia, choreoathetotic movements and dysarthria. Additional features may include sensory axonal neuropathy, cerebellar atrophy, and mild speech delay. Cognitive function is normal. Serum lactate levels are increased. Patient tissues show decreased levels and activity of mitochondrial respiratory complex IV.

Mitochondrial complex I deficiency, nuclear type 8

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN8 transmission pattern is consistent with autosomal recessive inheritance.

Mitochondrial complex I deficiency, nuclear type 29

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN29 transmission pattern is consistent with autosomal recessive inheritance.

Combined oxidative phosphorylation deficiency 15

An autosomal recessive, mitochondrial, neurologic disorder characterized by features of Leigh syndrome and combined oxidative phosphorylation deficiency. Clinical features include mild global developmental delay, white matter abnormalities, ataxia, incoordination, speech and reading difficulties, T2-weighted hyperintensities in the basal ganglia, corpus callosum, and brainstem.

Mitochondrial complex I deficiency, nuclear type 12

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease.

Maturity-onset diabetes of the young 11

A form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.

Hyperproinsulinemia

An autosomal dominant condition characterized by elevated levels of serum proinsulin-like material.

Deafness, aminoglycoside-induced

A form of sensorineural deafness characterized by moderate-to-profound hearing loss and mitochondrial inheritance. It is induced by exposure to aminoglycosides.

Infantile cerebellar-retinal degeneration

A severe autosomal recessive neurodegenerative disorder characterized by onset between ages 2 and 6 months of truncal hypotonia, athetosis, seizures, and ophthalmologic abnormalities, particularly optic atrophy and retinal degeneration. Affected individuals show profound psychomotor retardation, with only some achieving rolling, sitting, or recognition of family. Brain MRI shows progressive cerebral and cerebellar degeneration.

Lactate dehydrogenase B deficiency

A condition with no deleterious effects on health. LDHBD is of interest to laboratory medicine mainly because it can cause misdiagnosis in those disorders in which elevation of serum LDH is expected.

Pyruvate kinase hyperactivity

Autosomal dominant phenotype characterized by increase of red blood cell ATP.

Pompe disease, infantile-onset

An early-onset form of Pompe disease, an autosomal recessive lysosomal storage disease characterized by lysosomal alpha-glucosidase deficiency, a broad clinical spectrum and age at onset ranging from infancy to adulthood. The classic early-onset form of IOPD presents at birth with massive accumulation of glycogen in muscle, heart and liver. Cardiomyopathy and muscular hypotonia are the cardinal features of this form whose life expectancy is less than two years. A milder infantile form manifests as progressive muscular disorder of childhood and patients have better prognosis.

Perrault syndrome 4

An autosomal recessive, sex-influenced disorder characterized by sensorineural deafness in both males and females, and ovarian dysgenesis in females. Affected females have primary amenorrhea, streak gonads, and infertility, whereas affected males show normal pubertal development and are fertile.

Myoclonic epilepsy of Lafora 2

A form of progressive myoclonic epilepsy, a clinically and genetically heterogeneous group of disorders defined by the combination of action and reflex myoclonus, other types of epileptic seizures, and progressive neurodegeneration and neurocognitive impairment. MELF2 is an autosomal recessive, severe form characterized by onset of progressive neurodegeneration between 8 and 18 years of age. Initial features can include headache, myoclonic jerks, generalized seizures, and often visual hallucination. Typically, as seizures increase in frequency, cognitive function declines towards dementia, and affected individuals die usually within 10 years after onset. At the cellular level, MELF2 is characterized by accumulation of starch-like polyglucosans called Lafora bodies (LBs) that are most abundant in organs with the highest glucose metabolism: brain, heart, liver and skeletal muscle.

Auditory neuropathy and optic atrophy

An autosomal recessive disease characterized by hearing loss, visual impairment and optic atrophy, with onset in the first or second decades of life. Optic atrophy is caused by degeneration of nerve fibers which arise in the retina and converge to form the optic disk, optic nerve, optic chiasm and optic tracts.

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.

Mitochondrial complex V deficiency, nuclear type 5

A mitochondrial disorder characterized by childhood onset of episodic metabolic decompensation featuring lactic acidosis and hyperammonemia accompanied by ketoacidosis or hypoglycemia. Chronic manifestations include developmental delay, easy fatiguability, and 3-methylglutaconic aciduria. The transmission pattern of MC5DN5 is consistent with autosomal recessive inheritance.

Mitochondrial complex IV deficiency, nuclear type 2

An autosomal recessive, severe mitochondrial disorder characterized by hypotonia, global developmental delay, hypertrophic cardiomyopathy, lactic acidosis, gliosis, and neuronal loss in basal ganglia, brainstem and spinal cord. Serum lactate is increased, and laboratory studies show decreased mitochondrial complex IV protein and activity levels in various tissues, including heart and skeletal muscle. Most patients die in infancy of cardiorespiratory failure.

Mitochondrial complex IV deficiency, nuclear type 13

An autosomal recessive, infantile disorder with a fatal course in the first weeks of life, characterized by hypertrophic cardiomyopathy, left ventricular non-compaction, lactic acidosis, metabolic hypotonia, and mitochondrial complex IV deficiency.

Mitochondrial complex III deficiency, nuclear type 4

A disorder of the mitochondrial respiratory chain resulting in a highly variable phenotype depending on which tissues are affected. Clinical features include mitochondrial encephalopathy, psychomotor retardation, ataxia, severe failure to thrive, liver dysfunction, renal tubulopathy, muscle weakness and exercise intolerance.

Mitochondrial complex III deficiency, nuclear type 10

A form of mitochondrial complex III deficiency, a disorder of the mitochondrial respiratory chain resulting in a highly variable phenotype depending on which tissues are affected. MC3DN10 is an autosomal recessive form characterized by fetal bradycardia, poor feeding, hypotonia, hypertrophic cardiomyopathy, alopecia totalis, low mitochondrial complex III activity and lactic acidosis.

Mitochondrial complex I deficiency, nuclear type 3

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN3 transmission pattern is consistent with autosomal recessive inheritance.

Mitochondrial complex I deficiency, nuclear type 22

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN22 transmission pattern is consistent with autosomal recessive inheritance.

Mitochondrial complex I deficiency, nuclear type 21

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN21 transmission pattern is consistent with autosomal recessive inheritance.

Mitochondrial complex I deficiency, nuclear type 2

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN2 inheritance is autosomal recessive.

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.

Mitochondrial DNA depletion syndrome 5

A disorder due to mitochondrial dysfunction. It is characterized by infantile onset of hypotonia, neurologic deterioration, a hyperkinetic-dystonic movement disorder, external ophthalmoplegia, deafness, variable renal tubular dysfunction, and mild methylmalonic aciduria in some patients.

Maturity-onset diabetes of the young 8 with exocrine dysfunction

An autosomal dominant form of diabetes characterized by a primary defect in insulin secretion, exocrine pancreatic dysfunction, altered pancreatic morphology, recurrent abdominal pain, and fecal elastase deficiency. Disease onset is at less than 25 years of age.

Maturity-onset diabetes of the young 7

A form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.

Type 2 diabetes mellitus

A multifactorial disorder of glucose homeostasis caused by a lack of sensitivity to insulin. Affected individuals usually have an obese body habitus and manifestations of a metabolic syndrome characterized by diabetes, insulin resistance, hypertension and hypertriglyceridemia. The disease results in long-term complications that affect the eyes, kidneys, nerves, and blood vessels.

Maturity-onset diabetes of the young 1

A form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.

Pontocerebellar hypoplasia 6

A disorder characterized by an abnormally small cerebellum and brainstem, infantile encephalopathy, generalized hypotonia, lethargy and poor feeding. Recurrent apnea, intractable seizures occur early in the course of this condition.

Perrault syndrome 6

A form of Perrault syndrome, a sex-influenced disorder characterized by sensorineural deafness in both males and females, and ovarian dysgenesis in females. Affected females have primary amenorrhea, streak gonads, and infertility, whereas affected males show normal pubertal development and are fertile. PRLTS6 inheritance is autosomal recessive.

Spinocerebellar ataxia 28

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. SCA28 is an autosomal dominant cerebellar ataxia (ADCA) with a slow progressive course and no evidence of sensory involvement or cognitive impairment.

Glycogen storage disease 9D

A metabolic disorder characterized by slowly progressive, predominantly distal muscle weakness and atrophy. Clinical features include exercise intolerance with early fatigability, pain, cramps and occasionally myoglobinuria.

Mitochondrial complex IV deficiency, nuclear type 7

An autosomal recessive mitochondrial disorder characterized by encephalomyopathy resulting in variable clinical manifestations. Features include muscle weakness, gait disturbances, neurodegeneration, cognitive decline, metabolic acidosis, feeding difficulties, poor overall growth, cortical visual impairment, and hypertrophic cardiomyopathy. Serum lactate levels are increased. Patient tissues show decreased levels and activity of mitochondrial respiratory complex IV.

Mitochondrial complex IV deficiency, nuclear type 3

An autosomal recessive mitochondrial disorder characterized by cytochrome c oxidase deficiency. Clinical features include muscle weakness, hypotonia, ataxia, ptosis, metabolic acidosis, poor feeding, delayed motor development, anemia, sensorineural hearing loss, and cardiomyopathy.

Mitochondrial complex IV deficiency, nuclear type 1

An autosomal recessive disorder of the mitochondrial respiratory chain characterized by early-onset, rapidly progressive encephalopathy, neurodegeneration, and loss of motor and cognitive skills. Affected individuals show hypotonia, failure to thrive, loss of the ability to sit or walk, poor communication, poor eye contact, oculomotor abnormalities, as well as deafness, ataxia, tremor, and brisk tendon reflexes. Brain imaging shows bilateral symmetric lesions in the basal ganglia. Lactate levels in serum and cerebrospinal fluid are increased. Patient tissues show decreased levels and activity of mitochondrial respiratory complex IV. Death in childhood may occur, often due to central respiratory failure.

Mitochondrial complex II deficiency, nuclear type 1

A disorder of the mitochondrial respiratory chain with heterogeneous clinical manifestations. Clinical features include psychomotor regression in infants, poor growth with lack of speech development, severe spastic quadriplegia, dystonia, progressive leukoencephalopathy, muscle weakness, exercise intolerance, cardiomyopathy. Some patients manifest Leigh syndrome or Kearns-Sayre syndrome. MC2DN1 inheritance is autosomal recessive.

Mitochondrial complex I deficiency, nuclear type 6

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN6 transmission pattern is consistent with autosomal recessive inheritance.

Mitochondrial complex I deficiency, nuclear type 37

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN37 features include developmental delay, cerebral atrophy, epilepsy, growth retardation, congenital myopathy with disproportion of fibers, and severely decreased activity of complex I. MC1DN37 transmission pattern is consistent with autosomal recessive inheritance.

Mitochondrial complex I deficiency, nuclear type 17

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN17 transmission pattern is consistent with autosomal recessive inheritance.

Mitochondrial DNA depletion syndrome 17

An autosomal recessive mitochondrial disorder characterized by childhood onset of rapidly progressive encephalopathy, stroke-like episodes, lactic acidosis, hypocitrullinemia, multiple defects of oxidative phosphorylation, mitochondrial complex I and IV deficiency, and reduced mtDNA copy number.

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant, 2

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.

Hyperinsulinemic hypoglycemia, familial, 2

A form of hyperinsulinemic hypoglycemia, a clinically and genetically heterogeneous disorder characterized by inappropriate insulin secretion from the pancreatic beta-cells in the presence of low blood glucose levels. HHF2 is a common cause of persistent hypoglycemia in infancy. Unless early and aggressive intervention is undertaken, brain damage from recurrent episodes of hypoglycemia may occur. HHF2 inheritance can be autosomal dominant or autosomal recessive.

Pancreatic agenesis 1

A disease characterized by isolated hypoplasia or agenesis of the pancreas, pancreatic beta-cell failure resulting in neonatal insulin-dependent diabetes mellitus, and exocrine pancreatic insufficiency.

Glycogen storage disease 9A

A metabolic disorder resulting in a mild liver glycogenosis with clinical symptoms that include hepatomegaly, growth retardation, muscle weakness, elevation of glutamate-pyruvate transaminase and glutamate-oxaloacetate transaminase, hypercholesterolemia, hypertriglyceridemia, and fasting hyperketosis. Two subtypes are known: type 1 or classic type with no phosphorylase kinase activity in liver or erythrocytes, and type 2 or variant type with no phosphorylase kinase activity in liver, but normal activity in erythrocytes. Unlike other glycogenosis diseases, glycogen storage disease type 9A is generally a benign condition. Patients improve with age and are often asymptomatic as adults. Accurate diagnosis is therefore also of prognostic interest.