GRIN2D and neurodevelopmental disorder: Rare monoallelic and biallelic single nucleotide variants (SNVs) and copy number variants (CNVs) in genes encoding postsynaptic iGluRs subunits such as GRIN1, GRIN2A, GRIN2B, and GRIN2D encoding the NR1, NR2A, NR2B, and NR2D subunits of NMDAR, respectively, GRIA2‐4 encoding the GluR2‐4 subunits of AMPAR, and GRIK2 encoding the GluR6 subunit of KAR have been shown to cause a wide range of neurodevelopmental disorders (NDDs) and DEEs.4, 5, 6, 7, 8, 9, 10, 11