The hunt for causes of autism
Study tracks risks of 1,200 mothers
From testing blood to vacuuming dust at homes, researchers at four universities are following 1,200 mothers of autistic children to try to find clues to what causes the condition.
For many families, the quest for the causes of autism has grown more urgent with the news that the estimated prevalence of the condition grew by 23% from 2006 to 2008, a Centers for Disease Control and Prevention report said last week.
In most cases, however, scientists can’t tell parents what caused their child’s autism, says Thomas Insel, director of the National Institutes of Mental Health. In large part, the causes of autism — which is likely not one disease, but a group of conditions with related symptoms — remain a mystery.
For years, scientists had only a few clues about the condition, noticing that autism is about four times as common in boys as in girls, for example.
Recently, scientists have found a number of risk factors for autism, many of which point toward problems that develop very early in life — such as during pregnancy or delivery, or even during the process of creating eggs and sperm, says Craig Newschaffer, a professor at Philadelphia’s Drexel University.
To better understand causes of autism, researchers at four major universities are following 1,200 mothers of autistic children through the EARLI study, or the Early Autism Risk Longitudinal Investigation. Because researchers know that these mothers are at high risk of having a second autistic child, they closely follow the women’s subsequent pregnancies, testing blood, urine, hair, even vacuuming dust from the women’s homes, says Newschaffer, one of the study’s lead researchers. Researchers ask pregnant women to keep lists of any illnesses, because infections during pregnancy are suspected of playing a role in autism.
Doctors can reassure parents that one thing doesn’t cause autism: vaccines, says Paul Offit, chief of infectious diseases at Children’s Hospital of Philadelphia. Nearly two dozen studies have failed to find a link between autism and vaccines, whether given alone or in combination.