General description

Spinocerebellar ataxia type 6 (SCA6) is characterized as an autosomal dominant neurodegenerative disorder, resulting from an aberrant expansion of CAG trinucleotide repeats within the CACNA1A gene.

Within the spectrum of genetic spinocerebellar ataxias, the prevalence of this disease is second to Spinocerebellar ataxia 3 (SCA3). The typical age of onset ranges from the 40s to 50s, predominantly exhibiting symptoms of pure cerebellar ataxia. The occurrence of downbeat positioning nystagmus is significantly higher in SCA6, observed in 80-90% of cases, compared to other forms of spinocerebellar ataxia.

Familial hemiplegic migraine

Familial hemiplegic migraine follows an autosomal dominant inheritance pattern and is linked to mutations in three specific genes: CACNA1A, ATP1A2, and SCN1A (See Hemiplegic migraine). Notably, the CACNA1A gene is also associated with Spinocerebellar ataxia type 6 (SCA6), which can lead to cerebral ataxia in approximately 20% of patients.