What It Is

MED23 gene defect, also known as autosomal recessive nonsyndromic mental retardation-18, is a genetic neurological condition characterized by intellectual delays. 

It is autosomal and recessive, meaning that both parents carry some mutation on the MED23 gene and have a 25% chance of passing this gene onto their children. 

There are two families known to exist worldwide- one in Algeria where five siblings are affected, and a pair of brothers in the United States.

What This Means

MED23 is a gene found in the Mediator (MED) complex, a regulator of protein-coding gene expression. The MED complex assists with transcribing genetic data required for cells to duplicate. 

MED23 is thought to play a role in brain development and cognitive thinking, so mutations in this gene lead to global developmental delays. 


  • Difficulty swallowing and eating in infancy
  • Gastrointestinal complications in infancy
  • Screaming spells in first few years of life
  • Reflux symptoms in infancy
  • Unable to read, write, speak, walk, or use arms in purposeful manner
  • High muscle tone in arms and legs
  • Sensory issues, including poor eye focus and control, trunk and head control and spasticity of extremities 
  • Normal height, weight, and head circumference with no physical malformations

Treatments & Therapies

There is no cure for MED23 gene defect.