A group of neurological and neurodevelopmental disorders caused by pathogenic variants in genes encoding subunits of the N-methyl-D-aspartate (NMDA) receptor, including GRIN1, GRIN2A, GRIN2B, and GRIN2D. These disorders are associated with a spectrum of symptoms such as developmental delay, intellectual disability, epilepsy, movement disorders, speech and language impairment, and neuropsychiatric features. The clinical presentation and severity vary depending on the specific gene and mutation involved.