Rett Syndrome is most often caused by mutations in a gene called MECP2, on the X chromosome.
This gene makes a protein, also called MeCP2 (but written differently), which is necessary for normal brain function.
While Rett Syndrome remains a clinical diagnosis based on the child’s symptoms and history, the identification of MECP2 has made DNA testing and confirmation possible for affected individuals and their families. To date, approximately 95% of girls with a clinical diagnosis of Rett have a confirmed MECP2 mutation.
The incidence of recurrence in a family is less than 1%.