KCNQ2 syndrome is a rare genetic disorder caused by changes (mutations) in the KCNQ2 gene. This gene is important for the function of potassium channels in the brain, which control the electrical activity of nerve cells.

Children with KCNQ2 syndrome usually show epileptic seizures in the first few days of life. Developmental delay, mental retardation, muscle hypotonia (low muscle tone) and motor and speech difficulties are common. In some cases, there are also problems with swallowing and feeding.