What causes Rett syndrome?
Rett syndrome results from a chain of events which begin with a genetic mutation at the time of conception.
In October 1999, researchers at the Baylor College of Medicine in Houston discovered that mutations in the MECP2 gene were the main cause of Rett syndrome. To date, mutations in this gene had been found in 95% of individuals who have been diagnosed with the disorder, with over 900 unique mutations having been identified within the MECP2 gene.
The MECP2 gene contains instructions which enable genes to function properly. If it is not functioning properly, it allows genes to turn on or off at inappropriate times, thus disturbing the precisely regulated sequence necessary for proper development of a human’s central nervous system. Mutations in the MECP2 gene have also been detected in other neurological disorders such as MECP2 Duplication syndrome, severe neonatal encephalopathy, PPM-X syndrome, severe X-linked intellectual disability and autism.
Mutations in other genes which can cause symptoms of Rett syndrome include CDKL5, FOXG1, MEF2C and TCF4. Conditions caused by mutations in these genes are considered to be unique and as such, regarded as separate disorders to Rett syndrome.