RAI1 gene
The RAI1 gene provides instructions for making a protein that regulates gene expression, playing a critical role in brain development, craniofacial bone development, and circadian rhythms.
Normal Function
The RAI1 gene provides instructions for making a protein that is active in cells throughout the body, particularly nerve cells (neurons) in the brain. Located in the nucleus of the cell, the RAI1 protein helps control the activity (expression) of certain genes. While most of the genes regulated by RAI1 have not been identified, studies suggest this protein controls the expression of several genes involved in daily (circadian) rhythms, such as the sleep-wake cycle. The RAI1 protein also appears to play a role in the development of the brain and of bones in the head and face (craniofacial bones).
Health Conditions Related to Genetic Changes
Potocki-Lupski syndrome
Having an extra copy of the RAI1 gene in each cell is thought to underlie many of the major features of Potocki-Lupski syndrome. This condition is characterized by delayed development, mild to moderate intellectual disability, autism spectrum disorder, sleep disturbances, and other health problems.
- Cause: The condition results from abnormal copying (duplication) of a small piece of the short (p) arm of chromosome 17 at position p11.2.
- Mechanism: Studies suggest that the duplication increases the amount of RAI1 protein, which disrupts the expression of genes that influence circadian rhythms and brain development, leading to the neurological and developmental features of the condition.
Smith-Magenis syndrome
Researchers believe that a partial or total loss of function of the RAI1 gene accounts for most of the signs and symptoms of Smith-Magenis syndrome. The major features include mild to moderate intellectual disability, delayed speech and language skills, distinctive facial features, sleep disturbances, and behavioral problems.
- Cause: In most people, the condition results from a deletion of a small piece of chromosome 17 (17p11.2). A small percentage of people have a mutation in the RAI1 gene instead of a chromosomal deletion.
- Mechanism: The deletion leads to a reduced amount of RAI1 protein, which disrupts the expression of genes involved in circadian rhythms, accounting for sleep disturbances. It is unclear how the loss of one copy of the RAI1 gene leads to other physical and behavioral problems.
Yuan-Harel-Lupski syndrome
Having an extra copy of the RAI1 gene is thought to underlie many of the major features of Yuan-Harel-Lupski (YUHAL) syndrome, which is characterized by multiple neurological problems. This condition results from a duplication of a small piece of chromosome 17 (p12-p11.2).
- Mechanism: The duplications contain the RAI1 gene and a nearby gene called PMP22. Features such as delayed development, behavioral and sleep problems, and unusual facial features are likely caused by an extra copy of the RAI1 gene. Other features, such as muscle weakness and decreased sensitivity to touch, heat, and cold in the lower legs and feet, likely result from an extra copy of the PMP22 gene.
