MED13L

More than 50 mutations in the MED13L gene have been found to cause MED13L syndrome. This condition is characterized by moderate to severe developmental delay and intellectual disability and minor differences in facial features. Additionally, some people with MED13L syndrome have recurrent seizures (epilepsy) or heart abnormalities that are present from birth (congenital heart defects).

Some MED13L gene mutations insert or delete regions of DNA within the MED13L gene. These genetic changes lead to a reduction in the total amount of MED13L protein in cells. Other mutations change single protein building blocks (amino acids) in the MED13L protein. It is thought that the altered protein interferes with the function of the normal protein produced from the non-mutated copy of the MED13L gene (such mutations are described as "dominant-negative"). Because dominant negative mutations impair the function of proteins made from both the altered copy of the MED13L gene and the normal copy, individuals with dominant negative mutations tend to have more severe signs than people with mutations that affect protein production from just the altered copy of the gene. While it is likely that mutations in the MED13L gene impair the control of gene activity by the mediator complex, it is unclear how these changes lead to the particular cognitive and physical features of the disorder.

MedlinePlus Genetics provides information about Critical congenital heart disease