Phenotypes associated with the disease episodic ataxia type 8 (OMIM:616055):
- Myokymia (HP:0002411): Myokymia consists of involuntary, fine, continuous, undulating contractions that spread across the affected striated muscle. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:616055)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:616055)
- Episodic ataxia (HP:0002131): Periodic spells of incoordination and imbalance, that is, episodes of ataxia typically lasting from 10 minutes to several hours or days. Evidence: IEA. (OMIM:616055)
- Dysarthria (HP:0001260): Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:616055)
- Nonprogressive (HP:0003680): Applies to a disease manifestation that does not increase in scope or severity over the course of time, i.e., that does not worsen with age. Evidence: TAS. (OMIM:616055)
- Ataxia (HP:0001251): Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly). Evidence: TAS. (OMIM:616055)
- Slurred speech (HP:0001350): Abnormal coordination of muscles involved in speech. Evidence: TAS. (OMIM:616055)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: TAS. (OMIM:616055)
- Intention tremor (HP:0002080): A type of kinetic tremor that occurs during target directed movement is called intention tremor. That is, an oscillatory cerebellar ataxia that tends to be absent when the limbs are inactive and during the first part of voluntary movement but worsening as the movement continues and greater precision is required (e.g., in touching a target such as the patient's nose or a physician's finger). Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:616055)
- Autosomal dominant inheritance (HP:0000006): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: TAS. (OMIM:616055)