Parkinsonism-dystonia 2, infantile-onset

An autosomal recessive disorder characterized by infantile onset of abnormal movements, including parkinsonism, dystonia, and poor fine motor skills, as well as autonomic dysfunction, including abnormal sweating, cold extremities, and poor sleep. Some patients have variable degrees of developmental delay.

Ataxia telangiectasia

A rare recessive disorder characterized by progressive cerebellar ataxia, dilation of the blood vessels in the conjunctiva and eyeballs, immunodeficiency, growth retardation and sexual immaturity. Patients have a strong predisposition to cancer; about 30% of patients develop tumors, particularly lymphomas and leukemias. Cells from affected individuals are highly sensitive to damage by ionizing radiation and resistant to inhibition of DNA synthesis following irradiation.

Spinocerebellar ataxia 6

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. SCA6 is an autosomal dominant cerebellar ataxia (ADCA), mainly caused by expansion of a CAG repeat in the coding region of CACNA1A. There seems to be a correlation between the repeat number and earlier onset of the disorder.

Seizures, sensorineural deafness, ataxia, impaired intellectual development, and electrolyte imbalance

A complex disorder characterized by generalized seizures with onset in infancy, delayed psychomotor development, ataxia, sensorineural hearing loss, hypokalemia, metabolic alkalosis, and hypomagnesemia.

Episodic ataxia 1

An autosomal dominant disorder characterized by brief episodes of ataxia and dysarthria. Neurological examination during and between the attacks demonstrates spontaneous, repetitive discharges in the distal musculature (myokymia) that arise from peripheral nerve. Nystagmus is absent.

Dystonia 1, torsion, autosomal dominant

A primary torsion dystonia, and the most common and severe form. Dystonia is defined by the presence of sustained involuntary muscle contractions, often leading to abnormal postures. Dystonia type 1 is characterized by involuntary, repetitive, sustained muscle contractions or postures involving one or more sites of the body, in the absence of other neurological symptoms. Typically, symptoms develop first in an arm or leg in middle to late childhood and progress in approximately 30% of patients to other body regions (generalized dystonia) within about five years. 'Torsion' refers to the twisting nature of body movements observed in DYT1, often affecting the trunk. Distribution and severity of symptoms vary widely between affected individuals, ranging from mild focal dystonia to severe generalized dystonia, even within families.

Lissencephaly, X-linked 2

A classic type lissencephaly associated with abnormal genitalia. Patients have severe congenital or postnatal microcephaly, lissencephaly, agenesis of the corpus callosum, neonatal-onset intractable epilepsy, poor temperature regulation, chronic diarrhea, and ambiguous or underdeveloped genitalia.

Dystonia 3, torsion, X-linked

An X-linked dystonia-parkinsonism disorder. Dystonia is defined by the presence of sustained involuntary muscle contractions, often leading to abnormal postures. DYT3 is characterized by severe progressive torsion dystonia followed by parkinsonism. It has a well-defined pathology of extensive neuronal loss and mosaic gliosis in the striatum (caudate nucleus and putamen) which appears to resemble that in Huntington disease.

Dystonia 12

An autosomal dominant dystonia-parkinsonism disorder. Dystonia is defined by the presence of sustained involuntary muscle contractions, often leading to abnormal postures. DYT12 patients develop dystonia and parkinsonism between 15 and 45 years of age. The disease is characterized by an unusually rapid evolution of signs and symptoms. The sudden onset of symptoms over hours to a few weeks, often associated with physical or emotional stress, suggests a trigger initiating a nervous system insult resulting in permanent neurologic disability.

Episodic kinesigenic dyskinesia 1

An autosomal dominant form of paroxysmal kinesigenic dyskinesia, a neurologic condition characterized by recurrent and brief attacks of abnormal involuntary movements, triggered by sudden voluntary movement. These attacks usually have onset during childhood or early adulthood and can involve dystonic postures, chorea, or athetosis.

Neurodevelopmental disorder, mitochondrial, with abnormal movements and lactic acidosis, with or without seizures

An autosomal recessive, mitochondrial disorder with a broad phenotypic spectrum ranging from severe neonatal lactic acidosis, encephalomyopathy and early death to an attenuated course with milder manifestations. Clinical features include delayed psychomotor development, intellectual disability, hypotonia, dystonia, ataxia, and spasticity. Severe combined respiratory chain deficiency may be found in severely affected individuals.

Paroxysmal non-kinesigenic dyskinesia 1

An autosomal dominant movement disorder characterized by attacks of dystonia, chorea, and athetosis. The attacks of involuntary movements are brought on by stress, alcohol, fatigue or caffeine, and generally last between a few seconds and four hours or longer. The attacks may begin in one limb and spread throughout the body, including the face.

Episodic kinesigenic dyskinesia 3

A form of paroxysmal kinesigenic dyskinesia, a neurologic condition characterized by recurrent and brief attacks of abnormal involuntary movements. These attacks can involve dystonic postures, chorea, or athetosis. EKD3 is an autosomal dominant form with incomplete penetrance and onset in late childhood or early adolescence. Symptoms are usually triggered by sudden movement or stress, and resolve in most patients in their early twenties or later.

Dystonia 16

An early-onset dystonia-parkinsonism disorder. Dystonia is defined by the presence of sustained involuntary muscle contraction, often leading to abnormal postures. DYT16 patients have progressive, generalized dystonia with axial muscle involvement, oro-mandibular (sardonic smile) and laryngeal dystonia and, in some cases, parkinsonian features.

Parkinsonism-dystonia 1, infantile-onset

An autosomal recessive neurodegenerative disorder characterized by infantile onset of parkinsonism and dystonia. Other neurologic features include global developmental delay, bradykinesia and pyramidal tract signs.

Dystonia 26, myoclonic

A form of dystonia, a disorder defined by the presence of sustained involuntary muscle contraction, often leading to abnormal postures. DYT26 is an autosomal dominant, progressive disorder characterized by a combination of non-epileptic myoclonic jerks and dystonia. Affected individuals manifest myoclonic jerks in the upper limbs during the first or second decade of life, and later develop dystonia with predominant involvement of the craniocervical regions and sometimes the trunk and/or lower limbs.

GLUT1 deficiency syndrome 1

A neurologic disorder showing wide phenotypic variability. The most severe 'classic' phenotype comprises infantile-onset epileptic encephalopathy associated with delayed development, acquired microcephaly, motor incoordination, and spasticity. Onset of seizures, usually characterized by apneic episodes, staring spells, and episodic eye movements, occurs within the first 4 months of life. Other paroxysmal findings include intermittent ataxia, confusion, lethargy, sleep disturbance, and headache. Varying degrees of cognitive impairment can occur, ranging from learning disabilities to severe intellectual disability.

Dystonia 11, myoclonic

A myoclonic dystonia. Dystonia is defined by the presence of sustained involuntary muscle contractions, often leading to abnormal postures. DYT11 is characterized by involuntary lightning jerks and dystonic movements and postures alleviated by alcohol. Inheritance is autosomal dominant. The age of onset, pattern of body involvement, presence of myoclonus and response to alcohol are all variable.