[Autism and epigenetics. A model of explanation for the understanding of the genesis in autism spectrum disorders].

Autism spectrum disorders are characterized by impairment of social integration and language development and restricted interests. Autism spectrum disorders manifest during childhood and may have a varying clinical expression over the years related to different therapeutic approaches, behavior-modifying drugs, and environmental factors, among others. So far, the genetic alterations identified are not sufficient to explain the genesis of all these processes, as many of the mutations found are also present in unaffected individuals. Findings on the underlying biological and pathophysiological mechanisms of entities strongly associated with autism spectrum disorders, such as Rett, fragile X, Angelman, and fetal alcohol syndromes, point to the role of epigenetic changes in disorders of neurodevelopment. Epigenetic phenomena are normal biological processes necessary for cell and thus human life, especially related to embryonic development. Different phenomena that affect epigenetic processes (changes that change operation or expression of a gene, without modifying the DNA structure) have also been shown to be important in the genesis of neurodevelopmental disorders. Alterations in the epigenetic mechanism may be reversible, which may explain the variation in the autism phenotype over time. Here we analyze the normal epigenetic mechanisms, autism spectrum disorders, their association with specific entities associated with altered epigenetic mechanisms, and possible therapeutic approaches targeting these alterations.