GRM7 encodes metabotropic glutamate receptor 7 (mGluR7), a presynaptic G-protein-coupled glutamate receptor essential for modulating neurotransmission 1. The receptor functions by binding glutamate, which triggers conformational changes and G-protein signaling that inhibits adenylate cyclase activity, thereby regulating axon outgrowth through MAPK-cAMP-PKA signaling during neuronal development 1. At the synaptic level, mGluR7 modulates neurotransmitter release and synaptic plasticity at presynaptic terminals 2. GRM7 variants cause neurodevelopmental disorders with diverse phenotypes depending on inheritance pattern and mutational consequences. Biallelic mutations in GRM7 cause severe phenotypes including intellectual disability, seizures, microcephaly, developmental delay, hypomyelination, and brain atrophy 12. Both autosomal dominant and recessive inheritance patterns produce disease, with heterozygous mutations also contributing to neurodevelopmental pathology 2. Emerging evidence links GRM7 polymorphisms to psychiatric conditions including attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder, major depressive disorder, and schizophrenia 345. Additionally, GRM7 variants influence behavioral phenotypes including emotion regulation, stress responses, and predisposition to addiction 6. Pathogenic mechanisms involve excitotoxicity and neuroinflammation contributing to neurodegeneration 2.