NRXN3geneencodesneurexin-III which is a Neural Cell Adhesion Molecule (NCAM) with important synaptic functions in the brain. Neurexin-III deficiency could affect synapse development, synaptic signaling and neurotransmitter release. Hitherto, there is no related disorder in the OMIM due to NRXN3 mutation. In this study, two unrelated Iranian families with homozygous (NM_001330195.2:c.3995G>A, p.Arg1332His) and compound heterozygous (NM_001330195.2:c.4442G>A, p.Arg1481Gln; c.3142+3A>G) variants in...