Genetic testing for clinically suspected spinocerebellar ataxias: report from a tertiary referral centre in India
Spinocerebellar ataxias (SCAs) are a heterogeneous group of neurodegenerative syndromes, characterized by a wide range of muscular weakness and motor deficits, caused due to cerebellar degeneration. The prevalence of the syndromes of SCA varies across the world and is known to be linked to the instability of trinucleotide repeats within the high-end normal alleles, along with susceptible haplotype. We estimated sizes of the CAG or GAA repeat expansions at the SCA1, SCA2, SCA3, SCA12 and frataxin loci among 864 referrals of subjects to genetic counselling and testing (GCAT) clinic, National Institute of Mental Health and Neurosciences, Bengaluru, India, with suspected SCA. The most frequent mutations detected were SCA1 (\(n=100\) (11.6%)) and SCA2 (\(n=98\) (11.3%)) followed by SCA3 (\(n=40\) (4.6%)), FRDA (\(n=20\) (2.3%)) and SCA12 (\(n=8\) (0.9%)).
KeywordsCAG repeats genotyping India spinocerebellar ataxias
We thank J. Muralidharan for excellent technical support in DNA isolation and Varalakshmi for the data entry. This work was supported by Indian Council of Medical Research (ICMR/002/208/2012/00126) for project funds and salary support for Mahesh Kandasamy, Sowmya Devatha Venkatesh and Radhika Vaidyanathan. We also thank all the patients, their family members and volunteers for their participation and cooperation.
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