Since the increasing rates of diagnoses related to autism, a disorder that has researchers stumped about what causes it; a plethora of studies have been done to pinpoint the underlying root of it. Environmental issues, genetics, and foods are of the main factors that go under the microscope consistently in an effort to figure out what it is that contributes to the onset of this disorder.
One such study done last month by researchers in Denmark produced new findings and shed some clarity on autism and siblings. It found that those children whose older siblings had been diagnosed with autism, were about 7 times more likely to be diagnosed with autism themselves. The really interesting point is that siblings who share the same mother are at a higher risk of being diagnosed with autism, that siblings who share the same father. This goes on to suggest that either the prenatal environment is the main culprit, or the environment the mother herself is in.
The sample size of this study, a whopping 1.5 million children, was narrowed down from the period between January 1980 and December 2004. This led to the further identification of 464,057 sibling pairs sharing the same mother, and 484,189 pairs who shared the same father. After going through the Danish Psychiatric Central Register and sorting the children diagnosed with autism, researchers calculated what is called the “recurrence risk” between siblings of being diagnosed with autism. The results showed that children who shared a biological mother, had a higher risk of being diagnosed with autism, than those who shared a biological father.
However, these are not brand new findings. According to John Constantino, a professor of psychiatry and pediatrics at Washington University in St. Louis, “…These findings are consistent with those of previous studies. There’s a lot of convergence across these studies that supports a very high level of heritability for autism.”