retinoic acid induced 1
The RAI1 gene provides instructions for making a protein that is active in nerve cells in the brain. Although the function of this protein is unknown, it is thought to be involved in nervous system development. Within cells, the RAI1 protein may be part of a protein complex (a group of proteins that work together) that helps control the activity of certain genes.
Researchers believe that a change in the function of the RAI1 gene is responsible for most of the physical, mental, and behavioral features of Smith-Magenis syndrome. In most cases, one copy of the RAI1 gene in each cell is lost when a region of chromosome 17 that contains the gene is deleted. It is unclear how the loss of this gene leads to the characteristic signs and symptoms of this condition.
A small percentage of cases are caused by a mutation in the RAI1 gene instead of a chromosomal deletion. Although these individuals have many of the major features of Smith-Magenis syndrome (including intellectual disability, behavioral problems, and sleep disturbances), they are less likely than people with a chromosomal deletion to have short stature, hearing loss, and heart or kidney abnormalities. At least 12 RAI1 mutations have been identified in people with Smith-Magenis syndrome. These mutations lead to the production of a nonfunctional version of the RAI1 protein or reduce the amount of this protein that is produced in cells. Scientists are working to determine how a missing or abnormal RAI1 protein results in the varied features of this disorder.