Classic Rett syndrome is an X-linked condition known to be associated with a mutation in the MECP2 gene. This is a progressive neurodevelopmental disorder that primarily affects girls. There is usually normal development during the first 6 to 18 months of life followed by a short period of stagnation. Then there is regression in language and motor skills with additional features of stereotypic hand movements, lack of purposeful use of the hands, teeth grinding, periodic breathing, seizures and acquired microcephaly.

Atypical Rett syndrome is similar to classic Rett syndrome; however, patients tend to have either milder or more severe findings compared to classic Rett syndrome. Atypical Rett syndrome is associated with mutations in either FOXG1 or CDKL5 genes. Specifically, mutations in the CDKL5 gene can be associated with severe and early-onset seizure activity. A small percentage of male patients have also been described with atypical Rett syndrome.

Genetics Center’s Comprehensive Rett Syndrome Panel includes the following genes:

MECP2

FOXG1

CDKL5

Rett syndrome testing is also available on a single gene basis.