Intractable Rare Dis Res. 2019;8(3):194-197. (DOI: 10.5582/irdr.2019.01063)

Molecular spectrum and allelic frequency of different subtypes (1,2, 3, 6 and 7) of Spinocerebellar ataxia in the Indian population.

Vishwakarma P, Agarwal S

Spinocerebellar ataxia (SCA) is a rare, heterogeneous genetic group of disorders with overlapping clinical features that arises as a result of the degeneration of Purkinje cells. The most prominent clinical feature of SCA is difficulty with whole body movements. The aim of the current study was to analyze the allelic frequency of normal repeat sizes in different SCA subtypes in the north Indian population. Blood samples were collected from 200 subjects, DNA was extracted, and then multiplex PCR and fragment analysis were performed using the ABI-310 genetic analyzer. The prevalent cytosine-adenine-guanine (CAG) repeat size or allelic frequency for SCA1, 2, 3 , 6, and 7 were 29 repeats (59%), 21 repeats (72.5%), 23 repeats (13.1%), 9 repeats (30%), and 3 repeats (75%), respectively. Results indicated that the normal repeats are shifting to lower or upper ranges in the Indian scenario, and similar findings have been reported in other previous studies. Thus, this and other studies have suggested that the normal range of repeats for various SCA in the Indian scenario needs to be redefined and should be confirmed by studies with larger samples and by functional studies.

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