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MECP2 Duplication Syndrome

Unlike Rett syndrome, which is caused by mutations or deletions in the MECP2 gene, the symptoms that arise from the duplication syndrome are caused, as the name suggests, by having an area of the X chromosome (Xq28), which includes the MECP2 gene, erroneously duplicated. The section duplicated may vary from individual to individual and may also contribute to the severity of the disease.

The syndrome has been diagnosed mostly in boys. The majority inherits the duplication from their mothers, who are typically asymptomatic due to favorable X chromosome inactivation (the moms have inactivated the X chromosome that harbors the duplication). Carrier mothers have a 50% chance of passing on the duplication to their children.

The MECP2 duplication syndrome (MDS) may be quite prevalent. Preliminary studies suggest that 1% of cases of X-linked intellectual disability may be due to this syndrome. The core phenotypes in boys include infantile hypotonia, mild dysmorphic features, developmental delay, absent to minimal speech, recurrent infections, progressive spasticity especially of the lower limbs, ataxia, autistic features, and seizures. Females with MECP2 duplication without X chromosome inactivation skewing have been reported and present similarly to boys.

In an effort to leverage RSRT’s deep knowledge base and global scientific networks, the MECP2 Duplication Syndrome Fund at RSRT was created in 2010. The Fund puts the intellectual and scientific resources of RSRT immediately to work for the MDS community. The Fund exclusively supports research aimed at reversing MDS. 100% of every dollar contributed is invested in research — not a single penny goes to overhead.

To learn more about MDS and current research efforts please visit CURE MECP2 Duplication Syndrome.