 Patients affected with Yunis–Varon syndrome are homozygous, compound homozygous, or compound heterozygous for deleterious mutations in FIG4.Spongiform degeneration of mouse brains caused by altering PI3P to PI(3,5)P2 conversion is associated with human Charcot-Marie-Tooth disease and amyotrophic lateral sclerosis (ALS) by accumulation of Lc3II, p62, and LAMP2 proteins, which also contributes to inclusion body disease.Manipulation of this signaling lipid involves culturing fibroblasts obtained by insertion of ETn2-beta(early transposon 2-beta) into intron 18 of FIG4 gene in vacuolar membrane of mice labeled pale tremor (plt).