Molecular analysis of Friedreich's ataxia locus in the Indian population

OBJECTIVES: Friedreich's ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by expansion of GAA repeats in the frataxin gene. We have carried out the first molecular analysis at the Friedreich's ataxia locus in the Indian population. MATERIALS AND METHODS: Three families clinically diagnosed for Friedreich's ataxia were analyzed for GAA expansion at the FRDA locus. The distribution of GAA repeats was also estimated in normal individuals of Indian origin. RESULTS: All patients clinically diagnosed for Friedreich's ataxia were found to be homozygous for GAA repeat expansion. The GAA repeat in the normal population show a bimodal distribution with 94% of alleles ranging from 7-16 repeats. CONCLUSION: Indian patients with expansion at the FRDA locus showed typical clinical features of Friedreich's ataxia. The low frequency of large normal alleles (6%) could indicate that the prevalence of this disease in the Indian population is likely to be low.