Inherited Spinocerebellar Ataxia Segregates with Intra-Familial Genetic Heterogeneity in a Consanguineous Pakistani Family: A Report of a Potential Novel Candidate Gene.

Hereditary spinocerebellar ataxia (SCA) is a group of genetic neurodegenerative disorders caused by a variety of gene variants. At least 44 types of SCAs have been identified to date, and more than 35 genes and hundreds of variants have been reported that are associated with SCAs. We have investigated a Pakistani consanguineous six-generation family with SCA by using whole-exome sequencing analysis. We identified a reported SCA-associated variant, c.C2687G (p.P896R) in CACNA1A, in only a subgroup of the family, while a c.C262T (p.P88S) variant in ARFIP1 serves as a candidate pathogenic variant in the other subgroup as a possible novel cause of SCA. Our study showed that intra-familial heterogeneity may exist in SCA families and presented a candidate new causative gene for SCA.