Rett syndrome true is

(B) X-linked disorder # Rett syndrome, a common cause of (dominant) X-linked progressive mental retardation in females, is due to a mutation in a gene (MECP2) encoding a DNA-binding protein involved in transcriptional repression. As the X chromosome comprises only ~3% of germline DNA, then by extrapolation the number of genes that potentially contribute to clinical disorders affecting intelligence in humans must be potentially> Rett syndrome is a neurodevelopmental disorder of the grey matter of the brain that affects girls almost exclusively. The clinical features include small hands and feet and a deceleration of the rate of head growth (including microcephaly in some). Repetitive hand movements, such as wringing and/or repeatedly putting hands into the mouth, are also noted. Girls with Rett syndrome are prone to gastrointestinal disorders and up to 80% have seizures. They typically have no verbal skills, and about 50% of females are not ambulatory. Scoliosis, growth failure, and constipation are very common and can be problematic.