Evidence of somatic mosaicism for aMECP2 mutation in females with Rett syndrome: diagnostic implications

EDITOR-Rett syndrome (RTT) (MIM 312750) is an X linked dominant neurodevelopmental disorder that occurs almost exclusively in females. AVected girls are considered to have a normal perinatal period followed by a period of regression, loss of acquired purposeful manual and speech skills, hand wringing, gait disturbance, and growth retardation. 1 2 A gene for RTT has been identified in the Xq28 region which encodes the methyl-CpG