The first family case of spinocerebellar ataxia type 14 in Russia

Spinocerebellar ataxia type 14 (SCA14) is a rare neurodegenerative disease with a predominant cerebellar affection and autosomal dominant inheritance. A characteristic clinical presentation is slowly progressive cerebellar ataxia, hyperreflexia, cognitive impairment and movement disorders (dystonia and myoclonus). Clinical and genetic characteristics of the first familial case of SCA14 in Russia (a 77‑year‑old female patient) caused by heterozygous pathogenic mutation c.155G>C (p.Cys52Ser) in exon 1 in PRKCG gene (NM_002739.1) are presented. The total duration of the disease was 47 years, and the follow‑up period was 32 years. The disease phenotype corresponded to isolated ataxia with a slow rate of progression; brain MRI revealed atrophy of the cerebellar vermis and hemispheres, symmetrical hyperintensity of the dentate nucleus on T2‑weighted images. The features of the SCA14 clinical presentation and the effect of mutations in the regulatory and kinase domains of protein kinase C gamma on the formation of pure and complex phenotypes are discussed.