a review of the overlapping clinical presentation of rett and angelman syndromes, and their underlying mechanisms

rett syndrome is a neurodevelopmental disorder with a unique clinical presentation that occurs almost exclusively in females. angelman syndrome (happy-puppet syndrome) presents with a characteristic face, severe mental retardation, and epilepsy in 80 to 90 percent of cases. rett and angelman syndromes are both part of the spectrum of neurologic disorders associated with autism. their clinical presentations overlap in many ways with both presenting in later infancy with global developmental delays, severe speech and communication impairments, progressive microcephaly, seizures, autistic behaviors, and characteristic though different movement disorders and stereotypic hand movements. however, other features can help differentiate these disorders, but significant phenotypic overlap and variation in severity sometimes cloud the underlying diagnosis. rett syndrome results from a mutation in the mecp2 gene located on xq28 whereas angelman syndrome is caused by a deletion on region 15q11-q13 in a maternally derived chromosome 15 and is related to a variety of molecular genetic mechanisms. recent advances have uncovered interactions between these and other genes that affect the function and structure of neurons in the brain. also, the reversal of symptoms of rett syndrome in a mature mouse model suggests the possibility for treatment of these and perhaps other autism-related disorders in the future.