Rare Diseases Clinical Research Network: Neurophysiological Correlates

Inclusion Criteria: Individuals with RTT, MECP2 Dup, and RTT-related disorders (mutations or deletions in CDKL5 and FOXG1 genes) who are also enrolled in the RTT5211 Protocol, which collects longitudinal clinical and neurobehavioral data will be linked to the RTT5211 Protocol by their RDCRN identification numbers. No phenotypical selection of subjects will be performed; we expect the cohort will be representative of each disorder. A cohort of 60 typically developing girls and boys (30 each) will be enrolled to serve as controls. Typical development in the control group will be confirmed by normal intelligence quotient scores or equivalent scores on developmental tests using standardized measures and negative psychiatric diagnoses on a standardized diagnostic interview administered to their mothers, fathers or guardians (Diagnostic Interview for Children and Adolescents, Revised: Parents' Version). All control subjects must have a negative history of neurologic impairment or neuropsychiatric conditions and show no clinical evidence of a genetic disorder. Exclusion Criteria: Individuals who do not meet the above criteria will be excluded.