Environmental Factors Contributing To Autism
Evidence that environmental factors can contribute to autism has been around for several decades. The first clue comes from studies of monozygotic (‘identical’) twins, who share 100% of their inherited genes, but do not show complete concordance, i.e., one twin can have autism and the other not, or the two can be extremely different in terms of the severity of their symptoms. These discordant twin-pairs demonstrate that genes alone cannot tell the whole story: environment must explain part of the causal process in the neuropathology of these disorders.
