MECP2 and Rett syndrome: Although the strategy described above (exogenous gene expression) cannot immediately be applied to human patients, because it is not possible to insert a normal MECP2 gene into the patients prenatally, chemicals that activate the expression of MECP2 might work in patients with Rett Syndrome, since Rett syndrome patients (all females and heterozygous) have one normal MECP2 besides one mutant MECP2.