title: GRIN2B-related neurodevelopmental disorder
text: # GRIN2B-related neurodevelopmental disorder
  
  GRIN2B-related neurodevelopmental disorder is a rare neurodevelopmental disorder which is characterized by developmental delays and intellectual disabilities of variable degrees, muscle tone anomalies, feeding difficulties, and behavioral problems.
  
  ## Signs and symptoms
  
  The following list comprises most of the symptoms people with GRIN2B show:
  
  * Intellectual disability (mild to severe)
  * Developmental delay (mild to severe)
  * Hypotonia
  * Epilepsy
  * Autism spectrum disorder
  * Autistic-like behavior
  * Microcephaly
  * Hyperactivity
  * Stereotypy
  * Spasticity
  * Feeding difficulties
  
  Less common symptoms include:
  
  * Visual impairment
  * Dystonia
  * Dyskinesia
  * Other choreiform movement disorder
  
  ## Causes
  
  This condition is caused by mutations in the GRIN2B gene, located in chromosome 12.
  
  This gene makes instructions into how to make a protein called GluN2B, a type of NMDA receptor, which is found in brain neurons during ante-natal brain development. It is involved in correct brain development and function, regulating memory, synaptic plasticity and the ability of learning.
  
  ## Epidemiology
  
  Around 100 cases have been described in medical literature.
  
  