Deleterious Variants of FIG4, a Phosphoinositide Phosphatase, in Patients with ALS

Mutations of the lipid phosphatase FIG4 that regulates PI(3,5)P2 are responsible for the recessive peripheral-nerve disorder CMT4J. We now describe nonsynonymous variants of FIG4 in 2% (9/473) of patients with amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS). Heterozygosity for a deleterious allele of FIG4 appears to be a risk factor for ALS and PLS, extending the list of known ALS genes and increasing the clinical spectrum of FIG4-related diseases.