Spinocerebellar Ataxia Type 14

Excerpt

Clinical characteristics: Spinocerebellar ataxia type 14 (SCA14) is characterized by slowly progressive cerebellar ataxia, dysarthria, and nystagmus. Axial myoclonus, cognitive impairment, tremor, and sensory loss may also be observed. Parkinsonian features including rigidity and tremor have been described in some families. Findings seen in other ataxia disorders (e.g., dysphagia, dysphonia) may also occur in SCA14. The average age of onset is in the 30s, with a range from childhood to the seventh decade. Life span is not shortened.

Diagnosis/testing: The diagnosis of SCA14 is established in a proband with a pathogenic variant in PRKCG identified by molecular genetic testing.

Management: Treatment of manifestations: Physical therapy to maintain mobility and function; occupational therapy to optimize activities of daily living; adaptive devices to maintain/improve independence in mobility; clonazepam or valproic acid to help improve axial myoclonus; speech therapy and communication devices for those with dysarthria; modify food consistency to reduce aspiration risk; consider nutritional and vitamin supplementation to meet dietary needs.

Surveillance: At least yearly neurologic, physical medicine, and speech and language evaluation. Periodic assessment for dysphagia and assessment of cognitive abilities.

Agents/circumstances to avoid: Alcohol and sedation may make gait and coordination worse.

Genetic counseling: SCA14 is inherited in an autosomal dominant manner. Offspring of an affected individual have a 50% chance of inheriting the PRKCG pathogenic variant. Prenatal testing for pregnancies at increased risk is possible if the diagnosis has been established by molecular genetic testing in an affected family member.