Unstable FGF14 GAA repeat expansions in Indian ataxia patients: a broader phenotype and involvement of modifier loci?

Spinocerebellar ataxia (SCA27B), due to an intronic GAA repeat expansion in the FGF14 gene, has been described recently. We screened DNA samples for expanded FGF14 GAA repeats in individuals with movement disorder (N = 526) in our laboratory at NIMHANS, Bengaluru, India. Clinically pathogenic repeat expansions of FGF14 (GAA) were detected in 14 of 526 patients (2.

CAG Repeat Instability and Region-Specific Gene Expression Changes in the SCA12 Brain.

Spinocerebellar ataxia type 12 (SCA12), an autosomal dominant cerebellar ataxia, caused by an expansion of (CAG) in the 5' of the PPP2R2B gene on chr5q32, is common in India. The illness often manifests late in life, with diverse neurological and psychiatric symptoms, suggesting involvement of different brain regions. Prominent neuronal loss and atrophy of the cerebellum have been noted earlier.