An article at the Wall Street Journal discusses some recent advances in uncovering the causes of autism:
Scientists say that roughly 20% of autism cases can be linked to known genetic abnormalities, and many more may be discovered.
Pinpointing a genetic explanation can help predict whether siblings are likely to have the disorder — and even point to new, targeted treatments. Last week, for example, researchers reported that an experimental drug, arbaclofen, reduced social withdrawal and challenging behaviors in children and adults with Fragile X syndrome, the single most common genetic cause of autism.
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Autism spectrum disorder (ASD) is a collection of conditions that can range in severity from the social awkwardness and narrow interests seen in Asperger’s to severe communication and intellectual disabilities. ASD now affects 1 in every 88 U.S. children — nearly double the rate in 2002 — according to the Center for Disease Control and Prevention.
No single blood test or brain scan can diagnose autism spectrum disorders — in part because environmental factors also play a major role. But once a child is diagnosed, on the basis of symptoms and behavioral tests, researchers can work backward looking for genetic causes.
Both the American Academy of Pediatrics and the American College of Medical Genetics recommend that all children diagnosed with ASD be tested for Fragile X Syndrome and other chromosome abnormalities. The newest tests, called chromosomal microanalysis, can identify submicroscopic deletions or duplications in DNA sequences known to be associated with autism. Together, these tests find genetic explanations for more than 10% of autism cases.
