Investigation of SCA10 in the Cypriot population: further exclusion of SCA dynamic repeat mutations

Abstract

Autosomal dominant cerebellar ataxias (ADCAs) encompass a heterogeneous group of rare diseases that affect the cerebellum and its connections. The most common forms have been associated with dynamic mutations while some rarer forms with conventional mutations. Studies in different populations revealed differences in their relative frequencies both within and between the studied populations, showing that the frequencies are depended on ethnic and geographical factors. Previous investigation of triplet repeat expansion SCAs (SCA1, SCA2, SCA3, SCA6, SCA7, SCA8, SCA12, SCA17 and DRPLA) in the Cypriot population, revealed no pathogenic expansion in the Cypriot SCA patients. We hereby present our recent investigation of the SCA10 pentanucleotide repeat expansion. Forty-two ascertained Cypriot sporadic ataxia patients, the index case from 1 ADCA and 14 ARCA families and a cohort of normal population individuals were included in the study. All our patients have normal range ATXN10 gene ATTCT repeat numbers (10-19). In the normal population group, repeat lengths ranged from 11 to 20 with the 14 repeats allele being the most frequent. Therefore, all currently established dynamic repeat SCA mutations are absent from the Cypriot population, indicating distinct genetic causes.