Molecular and clinical correlation in five Indian families with spinocerebellar ataxia 12

Spinocerebellar ataxia 12 (SCA12) is a recently identified form of autosoma l dominant cerebellar ataxia associated with the expansion of an unstable C AG repeat in the 5' untranslated region of the gene PPP2R2B. We analyzed 77 Indian families with autosomal dominant cerebellar ataxia phenotype and co nfirmed the diagnosis of SCA12 in 5 families, which included a total of 6 p atients and 21 family members. The sizes of the expanded alleles ranged fro m 55 to 69 CAG repeats, and the sizes of the normal alleles ranged from 7 t o 31 repeats. We believe our study is the first to demonstrate that SCA12 m ay not be as rare in some populations as previously thought.