In one patient in the same study with autistic features before the age of 2 years, a rare missense mutation was detected by WES in FAAH2 encoding fatty-acid amide hydrolase 2 (FAAH2), which has a role in lipid metabolism and mediates degradation of endocannabinoids but had not been linked to neurological disorders. This evidence concerns the gene FAAH2 and nervous system disorder.