Rett Syndrome

Rett syndrome is a rare X-linked dominant neurodevelopmental disorder caused by mutations in the MECP2 gene, which encodes methyl-CpG-binding protein 2 (MeCP2), essential for normal brain development and function. Infants with Rett syndrome develop normally for the first 6-18 months, achieving normal developmental milestones. Then developmental regression occurs, characterized by loss of purposeful hand skills (replaced by stereotypic hand movements like hand wringing, hand clapping, or hand-to-mouth movements), loss of language and communication abilities, autistic-like behaviors, and progressive motor problems including ataxia, apraxia, and gait abnormalities. Seizures develop in 60-80% of patients. Heart rhythm abnormalities and breathing problems are common. Girls are usually non-ambulatory by age 10, though lifespan can extend into adulthood. Since affected boys typically die in utero or infancy, Rett syndrome predominantly affects girls.