GRM1, encoding metabotropic glutamate receptor 1 (mGluR1), is crucial in slow excitatory postsynaptic conductance, synapse formation, synaptic plasticity, and motor control [3]. It is mainly expressed in the brain, especially highly in the cerebellum, and is involved in multiple biological processes and disease-related pathways [3]. Genetic models can be valuable in studying its function.

In chondromyxoid fibroma (CMF), GRM1 is characterized by recurrent genetic rearrangements. These place it under the control of a constitutively active promoter, leading to increased gene expression. GRM1 immunohistochemistry can distinguish CMF from its histologic mimics, as it is positive in 97% of CMF specimens but negative in mimics [1,4,5]. In blue nevi and related melanomas, GRM1 gene fusions can be an alternative oncogenic driver, mutually exclusive of classical canonical mutations [2]. Mutations in GRM1 are also associated with congenital cerebellar ataxia, and in schizophrenia, deleterious GRM1 mutations may contribute to diverse psychiatric conditions [3,6].

In conclusion, GRM1 plays a significant role in neural-related functions such as synaptic plasticity and motor control. Its abnormal genetic alterations are associated with various diseases, including bone tumors, melanocytic neoplasms, cerebellar ataxia, and psychiatric disorders. The study of GRM1 using genetic models helps in understanding the underlying mechanisms of these diseases and may potentially lead to new diagnostic and therapeutic strategies.