Valproic Acid in Autism Spectrum Disorder: From an Environmental Risk Factor to a Reliable Animal Model

Autism spectrum disorders (ASD) have attracted public attention by its high prevalence, elevated social cost and large impact on the family [1]. Since the first descriptions of au‐ tism made by Hans Asperger in 1938 [2] and by Leo Kanner in 1943 [3, 4], much discus‐ sion has focused in the search for the triggering points of autism and identifying risk factors has become a high priority of scientists. Nevertheless, even after almost seventy years since the first reports, the etiology of autism remains unknown and its molecular basis is not well understood. Environmental factors (such as virus, bacteria, drugs, etc.) known to increase the risk of autism have critical periods of action during embryogene‐ sis. Congenital syndromes are found in high rates in patients with autism including so‐ matic changes originated early in the first trimester [5].