- Paresthesia (HP:0003401): Abnormal sensations such as tingling, pricking, or numbness of the skin with no apparent physical cause. Evidence: IEA. (OMIM:108500)
- Gaze-evoked nystagmus (HP:0000640): Nystagmus made apparent by looking to the right or to the left. Evidence: IEA. (OMIM:108500)
- Abnormal vestibular function (HP:0001751): An abnormality of the functioning of the vestibular apparatus. Evidence: TAS. (OMIM:108500)
- Diplopia (HP:0000651): Diplopia is a condition in which a single object is perceived as two images, it is also known as double vision. Evidence: IEA. (OMIM:108500)
- Vertigo (HP:0002321): An abnormal sensation of spinning while the body is actually stationary. Evidence: IEA. (OMIM:108500)
- Myotonia (HP:0002486): An involuntary and painless delay in the relaxation of skeletal muscle following contraction or electrical stimulation. Evidence: IEA. (OMIM:108500)
- Dystonia (HP:0001332): An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk. Evidence: TAS. (OMIM:108500)
- Migraine (HP:0002076): Migraine is a chronic neurological disorder characterized by episodic attacks of headache and associated symptoms. Evidence: IEA. (OMIM:108500)
- 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:108500)
- 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: IEA. (OMIM:108500)
- Tinnitus (HP:0000360): Tinnitus is an auditory perception that can be described as the experience of sound, in the ear or in the head, in the absence of external acoustic stimulation. Evidence: IEA. (OMIM:108500)
- Saccadic smooth pursuit interruptions (HP:0001152): An abnormality of tracking eye movements in which smooth pursuit is interrupted by an abnormally high number of saccadic movements. Evidence: IEA. (OMIM:108500)
- Progressive cerebellar ataxia (HP:0002073). Evidence: IEA. (OMIM:108500)
- Downbeat nystagmus (HP:0010545): Downbeat nystagmus is a type of fixation nystagmus with the fast phase beating in a downward direction. It generally increases when looking to the side and down and when lying prone. Evidence: IEA. (OMIM:108500)
- Typified by incomplete penetrance (HP:0003829): Description of conditions in which not all individuals with a given genotype exhibit the disease. Penetrance is the proportion that develop disease given a lifespan of 80 years. Evidence: IEA. (OMIM:108500)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: TAS. (OMIM:108500)
- 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: IEA. (OMIM:108500)
- Cerebellar vermis atrophy (HP:0006855): Wasting (atrophy) of the vermis of cerebellum. Evidence: IEA. (OMIM:108500)
These phenotypes are associated with the disease episodic ataxia type 2 (OMIM:108500).