Research newly published in PNAS, Proceedings of the National Academy of Sciences, helps to clarify how the MeCP2 protein regulates genes, and may help provide an explanation of the role of MECP2-related disorders in autism. Researchers at Harvard University and the Washington University School of Medicine published their findings showing that MeCP2 plays a particular role in regulating very long genes in the brain. They found that MeCP2 reduced the activity of genes in proportion to the number of available sites for methylation. Therefore, the longer the gene, the greater the role of MECP2 in regulating the gene, and thus the very long genes in the brain are most sensitive to changes in levels of MeCP2.
Previous research has suggested that the function of very long genes in the brain may be a common denominator in at least many of the underlying causes of autism. This new finding may suggest that both the underactivity of the MECP2 gene found in Rett syndrome and overactivity of the MECP2 gene found in MECP2 duplication syndrome may result in impaired responsiveness of these very long genes, potentially producing symptoms of autism.
Note: Increasingly, geneticists have been moving toward viewing autism, not so much as a single condition or primary disorder, but rather as a common symptom or symptom cluster produced by a collection of specific conditions referred to as autisms. For more on this see Concepts of Autism, Quasi-Autisms and Autisms?
MECP2 Duplication Syndrome Blog 