FAAH2 and Intellectual disability: The nearest protein-coding gene to rs2499550 is FAAH2, which is expressed in the brain, amongst other tissues.46 Moreover, FAAH2 has been linked to X-linked recessive neuropsychiatric disorders, including intellectual disabilities and Autism spectrum disorder.47 The second lead locus, rs58045540, has not been functionally linked to a protein-coding gene.