A), Architecture and domain organization for the NMDAR. B), Summary of NMDAR variants in different GRIN subunits and domains. C), Summary of GRIN variant-associated phenotypes. ATD: amino terminal domain, ABD: agonist binding domain, TMD-link: transmembrane domains (M1-4) and linker regions, CTD: intracellular carboxy-terminal domain. ASD: Autism Spectrum Disorder, CVI: cortical visual impairment, Epi: epilepsy/seizures, Hypo: hypotonia, ID/DD: intellectual disability/developmental delay; LP/SP: language/speech problems; MD: movement disorders; Sleep: sleep problems. Many individuals showed multiple phenotypes, which are only a snapshot of the current literature, which is disproportionally weighted by different diagnostic approaches and ascertainment.