MECP2 duplication syndrome in both genders

Brain Dev. 2013 May;35(5):411-9. doi: 10.1016/j.braindev.2012.07.010. Epub 2012 Aug 9.


Background: Duplications involving the methyl-CpG-binding protein 2 gene (MECP2) locus at Xq28 have been frequently identified in male patients who exhibit a phenotype unique from that of Rett syndrome, which is mainly characterized by severe mental retardation, recurrent infections, and epilepsy. This combination of features is recognized as MECP2 duplication syndrome.

Methods: Genomic copy number was investigated for patients with unexplained mental retardation, and phenotypic features of the patients having interstitial duplications including MECP2 were analyzed.

Results: Three male and one female patients with MECP2 duplication were identified. The phenotypic features of all the four patients were compatible with MECP2 duplication syndrome. The X-chromosome inactivation (XCI) pattern was analyzed in the female patient, identifying a skewed XCI that activated the X-chromosome containing the MECP2 duplication. Her mother possessed the same MECP2 duplication and a random XCI pattern but exhibited no phenotypic features, indicating a nonsymptomatic carrier. The brain magnetic resonance imaging revealed periventricular cystic lesions in all four patients, including the female patient.

Conclusion: This study suggested clinical implications of the MECP2 duplication syndrome not only in the male but also in female patients with unexplained mental retardation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Brain / pathology
  • Child, Preschool
  • Chromosome Mapping
  • Female
  • Gene Duplication / genetics*
  • Humans
  • Intellectual Disability / etiology
  • Intellectual Disability / genetics
  • Magnetic Resonance Imaging
  • Male
  • Mental Retardation, X-Linked / diagnosis
  • Mental Retardation, X-Linked / genetics*
  • Methyl-CpG-Binding Protein 2 / genetics*
  • Phenotype
  • X Chromosome Inactivation / genetics*
  • Young Adult


  • Methyl-CpG-Binding Protein 2

Supplementary concepts

  • Lubs X-linked mental retardation syndrome