ARSA and metachromatic leukodystrophy: Previous studies have described other pathogenic mutations (p.K304R, p.K304 N, p.T306 M, p.Y308H, p.E309Q, p.E309*, p.G310D, p.G311S, and p.R313Q) in the disulfide bond region of ARSA (Cesani et al., 2016), which may cause MLD.