Written by Dr Hannah Shorrock Edited by Larissa Nitschke
Repeat interruptions in SCA10 influence repeat tract stability and are associated with epileptic seizures
Multiple spinocerebellar ataxias (SCAs) are caused by repeat expansion mutations, but in some cases, these repeat expansions are interrupted. The presence of repeat interruptions can influence disease symptoms and how the repeat expansion behaves. This is the case for SCA10. Some patients with SCA10 have a series of repeat interruptions, which are referred to as an ATCCT repeat interruption motif. In SCA10 patients with this interruption motif, Dr. Ashizawa and his team found an increased risk of developing epileptic seizures and identified that the interruptions influence the local stability of the repeat expansion.
SCA10 is a dominantly inherited ataxia caused by an ATTCT repeat expansion in the Ataxin 10 gene (ATXN10). Unaffected individuals usually carry 9-32 ATTCT repeats, while SCA10 patients carry an expansion of up to 4500 repeats. SCA10 patients suffer from cerebellar ataxia, but some patients also have other symptoms, including epileptic seizures. Dr. Ashizawa and his team were interested in why some patients with SCA10 suffer from epileptic seizures, but others do not.
Initially, the group investigated whether the length of the ATXN10 repeat expansion correlated with epileptic seizures. They found no difference in repeat length between 37 SCA10 patients who developed epilepsy and 51 who did not. This shows that repeat length does not influence whether or not SCA10 patients develop epileptic seizures.Continue reading “Repeat interruptions are associated with epileptic seizures in SCA10”