An article published in Science News, January 12, 2008, p. 19, reports on recent studies attempting to unravel the possible genetic causes of autism.
Geneticist Mark J. Daly of Massachusetts General Hospital in Boston has found a small stretch of chromosome 16 that promotes autism when it is in an altered form. It is found in about 1% of children with the disorder. The study looked at 751 families with two or more children with autism or a related disorder, for a total of 1,441 affected children. The researchers found additional evidence of both DNA deletion and extra copies of genes within the chromosome 16 area in children diagnosed with autism. In most of the cases, the altered genes arose spontaneously, but some were inherited from parents.
Another study, led by geneticist Aravinda Chakravati of the Johns Hopkins University School of Medicine in Baltimore, identified a small area of chromosome 7 that showed a link to autism. A specific gene on chromosome 7 makes a protein essential for neural communications.
In another study reported in Science News, September 29, 2007, p. 197, researchers found no association between Mercury in vaccines and climbing autism rates. The study was funded by the Centers for Disease Control and Prevention and enrolled 1,047 children from 7 - 10 years old. The researchers compared the amount of Themerosol, a Mercury based preservative used in vaccines, that children received through the first 7 months of life and the results of a battery of tests for language, memory, motor coordination, attention, and intelligence. They found no correlation between the amount of Mercury the children received and performance on the tests.
In another study by the California Department of Public Health, researcher Robert Schechter found that the prevalence of autism in children aged 3 - 12 years old has increased gradually from 1995 to 2007, even though Themerosol was removed from vaccines from 1999 - 2001.
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