chromodomain helicase DNA binding protein 2
The CHD2 gene provides instructions for making a protein called chromodomain DNA helicase protein 2. This protein is found in cells throughout the body and regulates gene activity (expression) through a process known as chromatin remodeling. Chromatin is the complex of DNA and proteins that packages DNA into chromosomes. The structure of chromatin can be changed (remodeled) to alter how tightly DNA is packaged. When DNA is tightly packed, gene expression is lower than when DNA is loosely packed.
At least 30 mutations in the CHD2 gene have been found to cause CHD2 myoclonic encephalopathy, a condition characterized by recurrent seizures (epilepsy), abnormal brain function (encephalopathy), and intellectual disability beginning in childhood. About half of these mutations delete pieces of DNA from the CHD2 gene. These and other CHD2 gene mutations either prevent the production of any chromodomain DNA helicase protein 2 or lead to the production of a nonfunctional version of the protein. As a result, chromatin remodeling and gene expression normally regulated by the chromodomain DNA helicase protein 2 are disrupted. It is unclear why CHD2 gene mutations seem to only affect nerve cells in the brain or how they lead to the signs and symptoms of CHD2 myoclonic encephalopathy.
- ATP-dependent helicase CHD2