A flurry of new research offers some intriguing clues into the mystery of what causes autism, which in the past, has been blamed on everything from childhood vaccines to poor parenting.
Recently, the CDC reported that 1 in 88 eight-year-old children have autism spectrum disorder (ASD), an alarming 78 percent increase from 2002 when the number was 1 in 150. But whether the prevalence of autism is actually increasing is a subject of hot debate among experts, because it’s hard to tell how much of the increase is due to a broader definition for the disorder, improved detection methods that are leading to earlier diagnosis,or other factors still to be uncovered. One thing is certain: the more than one million children who suffer from autism and their families need help: the Autism Society states that the lifetime cost of caring for a child with autism ranges from $3.5 – $5 million.
Autism is a complicated developmental disability that usually appears by the age of three. It includes a range of brain abnormalities that affect how children communicate and interact with others, and it affects them in different ways and in varying degrees. Signs of autism may include a lack of or a delay in speech development, repetitive mannerisms, little eye contact or interaction with people, or lack of interest in play. Children do not “outgrow” autism, but early diagnosis and early intervention can lead to improved outcomes.There is no known single cause and mysteriously, the rate for boys is five times greater than for girls.
Scientists are now making major strides forward to solve the autism puzzle.
While it was previously thought that there were about 200 genes responsible, three new groundbreaking studies recently published in Nature suggest that there may be as many as 1000 high-risk autism genes responsible.
In one of the three genetic sequencing studies, researchers found that mutations known to increase the risk for autism are four times as likely to come from the father’s sperm as from the mother’s egg. They also found that the risk of passing on a genetic mutation to the child rises directly with the father’s age, a worrying finding as the average age of fathers rises. The research looked for disruptions in genetic code in a large sample of 209 families, where the child had autism and both parents did not.
“This was the first time we have been able to be definitive and point conclusively to paternal risk and age factors. A large epidemiological study from Denmark a few years ago suggested an association with paternal age. In our research, we found a clear genetic link, not just an epidemiologic link,” says Raphael Bernier, Ph.D., clinical psychologist with the University of Washington Autism Center and one of the principal investigators for the study.
In a population study published recently in the journal Pediatrics, researchers examined whether metabolic conditions during pregnancy – diabetes, hypertension and obesity, were associated with higher rates of autism. They found that obese mothers were 67 percent more likely to have a child with ASD than normal-weight mothers who did not have high blood pressure or diabetes. This is alarming, given that 34 percent of American women are obese now and current estimates project that 42 percent will be obese by the year 2030.
The study results suggest that increased insulin resistance, often seen in obese mothers, might be harming a baby’s brain development before birth. “If the mother has high blood sugar levels, that crosses the placenta and the baby has to produce it’s own insulin. As insulin is a growth promoter, and if the baby is growing faster, it needs a bigger supply of oxygen. If it doesn’t get the oxygen it needs, that can affect brain cell development,” says Paula Krakowiak, a Ph.D. Candidate in Epidemiology affiliated with the UC Davis MIND Institute and a researcher for the study.
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Originally commissioned by GE Healthy Outlook. Copyright Jane Langille.