FIG4 and Charcot-Marie-Tooth disease type 4J: In 2007, Meisler et al identified an autosomal recessive form of the disease, designated CMT4J that is caused by mutations in sac3 (Fig4), the PtdIns(3,5)P2 phosphatase that takes part in the PAS complex.74 In the same publication, the authors also describe a “pale tremor” phenotype in mice generated on a mixed inbred strain background.