The repeat variant in MSH3 is not a genetic modifier for spinocerebellar ataxia type 3 and Friedreich’s ataxia

Wai Yan Yau, Mafalda Raposo, Conceição Bettencourt, Robyn Labrum, João Vasconcelos, Michael H Parkinson, Paola Giunti, Nicholas W Wood, Manuela Lima, Henry Houlden, , Brain, , awaa043, https://doi.org/10.1093/brain/awaa043

MSH3 is a DNA mismatch repair gene whose product is essential for CAG repeat expansion and whose inactivation limits the expansion (Dragileva et al., 2009). The study conducted by Flower et al. demonstrates that a three-repeat allele in the mismatch repair gene MSH3 has potential disease-modifying effect on Huntington’s disease and myotonic dystrophy type 1 (DM1) (Flower et al., 2019), both of which are CAG repeat expansion disorders with distinct phenotypic features. The authors postulated that these effects are mediated through the influence of the MSH3 variant on the rate of somatic expansion.


The repeat variant in MSH3 is not a genetic modifier for spinocerebellar ataxia type 3 and Friedreich’s ataxia