GTR Home > Conditions/Phenotypes > MECP2 duplication syndrome


Excerpted from the GeneReview: MECP2 Duplication Syndrome
The MECP2 duplication syndrome is a severe neurodevelopmental disorder characterized by infantile hypotonia, delayed psychomotor development leading to severe intellectual disability, poor speech development, progressive spasticity, recurrent respiratory infections (in ~75% of affected individuals), and seizures (in ~50%). MECP2 duplication syndrome is 100% penetrant in males. Occasionally females have been described with a MECP2 duplication and related clinical findings, often associated with concomitant X-chromosomal abnormalities that prevent inactivation of the duplicated region. Generalized tonic-clonic seizures are most often observed; atonic seizures and absence seizures have also been described. One third of affected males are never able to walk independently. Almost 50% of affected males die before age 25 years, presumably from complications of recurrent infection and/or neurologic deterioration. In addition to the core features, autistic behaviors and gastrointestinal dysfunction have been observed in several affected boys. Although interfamilial phenotypic variability is observed, severity is usually consistent within families.

Genes See tests for all associated and related genes

  • Also known as: AUTSX3, MRX16, MRX79, MRXS13, MRXSL, PPMX, RS, RTS, RTT, MECP2
    Summary: methyl-CpG binding protein 2

Clinical features


Show allHide all

IMPORTANT NOTE: NIH does not independently verify information submitted to the GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in the GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Support Center