GRIN-related disorders comprise a spectrum of neurodevelopmental disorders related to pathogenic variants in one of the four currently known disease-associated GRIN genes, GRIN1, GRIN2A, GRIN2B, and GRIN2D – all encoding subunits of the N-methyl-D-aspartate receptor (NMDAR) [1–4]. This evidence concerns the gene GRIN2B and neurodevelopmental disorder.