A recent study that examined the somatic instability of the FGF14 GAA•TTC repeat in peripheral tissues matched with post-mortem brains and uncovered a tendency for the repeat to expand somatically in cerebellar tissue.41 In our study, all five pathologically confirmed MSA cases with FGF14 GAA>300 expansions were tested on DNA extracted from the cerebellum, which might account for the higher frequency of positive cases identified in this MSA cohort. This evidence concerns the gene FGF14 and multiple system atrophy.