GRIN (GRIN1, GRIN2A, GRIN2B, GRIN2C, GRIN2D, GRIN3A, GRIN3B)

The term “GRIN” refers to a family of genes that encode subunits of the N-methyl-D-aspartate (NMDA) receptors, which are critical components of the nervous system involved in synaptic transmission and plasticity. NMDA receptors are a type of glutamate receptor that plays key roles in neuronal development, learning, memory, and neuroplasticity. They are ionotropic receptors that function as ion channels, allowing ions to pass through the cell membrane in response to the binding of glutamate and other co-agonists, such as glycine or D-serine.

The GRIN gene family includes several members, each encoding different subunits of the NMDA receptor:

GRIN1: Encodes the GluN1 subunit, an essential component of all NMDA receptors. The GluN1 subunit is necessary for the formation and functioning of the receptor.
GRIN2A, GRIN2B, GRIN2C, GRIN2D: These genes encode the GluN2A, GluN2B, GluN2C, and GluN2D subunits, respectively. These subunits confer distinct pharmacological and electrophysiological properties to the NMDA receptors, influencing their kinetics, calcium permeability, and sensitivity to voltage-dependent magnesium block. The combination of GluN1 with different GluN2 subunits allows for a diversity of NMDA receptor subtypes with specific functions across different brain regions.

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GRIN gene variants: Details and symptoms

GRIN1

GRIN1 SYMPTOMS Some of the most common health issues and symptoms among GRIN1 patients, as reported by parents of patients in 2019. Common Intellectual disability / global developmental delay Epilepsy / seizures (from birth, or may develop later) Muscular hypotonia (low tone that can cause feeding difficulties and/or constipation) Cortical

GRIN2A

The impact of GRIN2A can vary greatly among individuals, with some experiencing severe symptoms and others having milder effects. Treatment often focuses on managing symptoms, especially seizures, through medication and supportive therapies. Since GRIN2A-related disorders can significantly affect communication and cognitive development, speech therapy and special educational support are also

GRIN2B

Pathogenic changes in the GRIN2B gene have been associated with several neurodevelopmental disorders, including intellectual disability, epilepsy, autism spectrum disorder (ASD), and attention deficit hyperactivity disorder (ADHD). These conditions can range in severity, affecting cognitive, motor, and social development to varying degrees. The symptoms and their intensity can vary widely

GRIN2C

Pathogenic changes in the GRIN2C gene can lead to various neurological and psychiatric conditions, although they are less commonly reported than variants in some of the other NMDA receptor subunit genes, like GRIN2A and GRIN2B. The conditions associated with GRIN2C variants might include developmental delay, intellectual disability, epilepsy, and potentially

GRIN2D

Changes in the GRIN2D gene have been less frequently reported in comparison to variants in other NMDA receptor subunit genes but can be associated with various neurological disorders. These might include developmental delays, intellectual disability, epilepsy, and other conditions affecting the nervous system. The specific role of GRIN2D variants in