There is a substantially higher risk of autism in identical twins as compared to fraternal twins. In 88 percent of the time, if one identical twin develops autism, the other does, as well. In fraternal twins, the rate is 31 percent.
Identical twins also had similar levels of day-to-day functioning and cognitive deficits as well as similarities in the form of autism they developed.
The study involved 277 twin pairs with at least one of the twins diagnosed with an autistic disorder. 210 of the pairs were fraternal It was published last month in the Archives of Pediatrics & Adolescent Medicine . In a study headed by Dr. Paul Law of the Kennedy Krieger Institute in Baltimore. In the study, with identical twins, all females involved had been diagnosed with an ASD. The percentage of twin paris of males involved in the study was 86 percent.
Among fraternal twins, the numbers changed. In pairs of twins where both were males, when one twin developed an autistic disorder, 40 percent of the time, the other did as well. In females, when one twin developed an autistic disorder, the second twin did so in 20 percent of the time.
Genetics is but one aspect in autism research. Environmental factors may also be involved as well to make developing autism more probable in a certain subset of children.
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