SLC33A1 and Autosomal dominant spastic paraplegia type 42: We have previously demonstrated that SLC33A1 p.Ser113Arg (S113R) (c.339T>G) (MIM# 603690.0001) mutation causes autosomal-dominant spastic paraplegia type 42 (SPG42, MIM#612539) in humans (Lin et al., 2008).