|Number of repeats||Counts (alleles)||Percentage|
Overview of repeats
Spinocerebellar ataxia type 31 (SCA31) is caused by an insertion of a long stretch of TGGAA repeats in intron of BEAN1 gene, which was inserted as a complex before a stretch of TAAAA as found by Sato et al. (2009). In homozygous patients, the inserted sequence was determine to have the following confirmation: [TCAC-(TGGAA)exp(TAGAA)exp(TAAAA TAGAA)exp]. In healthy controls, TGGAA repeats were not found. However, in two cases an expansion in the region was found, but which also did not include the pathogenic motif, having the following confirmation: [TCAC-(TAGAA)exp(TAAAA TAGAA)exp]. The size of the inserted sequence complex was found to be between 2.5-3.8 kb, corresponding to approximately 500 and 760 pentanucleotide repeats (Sato et al., 2009).