>>11303104Autism is associated with a combination of genetic and environmental factors.[7] Risk factors during pregnancy include certain infections, such as rubella, toxins including valproic acid, alcohol, cocaine, pesticides, lead, and air pollution, fetal growth restriction, and autoimmune diseases.[18][19][20] Controversies surround other proposed environmental causes; for example, the vaccine hypothesis, which has been disproven.[21] Autism affects information processing in the brain and how nerve cells and their synapses connect and organize; how this occurs is not well understood.[22] The Diagnostic and Statistical Manual of Mental Disorders (DSM-5), combines autism and less severe forms of the condition, including Asperger syndrome and pervasive developmental disorder not otherwise specified (PDD-NOS) into the diagnosis of autism spectrum disorder (ASD).[6][23]
