But a recent study out of the University of Toronto turns this idea on its head. Researchers analyzed the DNA of 170 subjects diagnosed along the spectrum and discovered that 69 percent of siblings had different mutations.
"Siblings with a diagnosis of autism do not share the same genetic risk factors for the disorder and are as distinct in their behaviors as any brothers and sisters," reports The New York Times.
The findings, which suggest that it may be a coincidence that random mutations occur in sibling DNA, may make sense to parents raising more than one child with autism, and who can see personality differences.
So what will researchers continue to do now?
The answer is going to blow your mind.
Researchers are currently building a massive database that will contain whole genomes of "10,000s of individuals with autism(s)," says Dr. Stephen Scherer, from The Hospital for Sick Children in Toronto, the study's lead author.
He believes the database will have enormous potential for changing how doctors diagnose and treat ASD. "In the future, once there is a suspected diagnosis of autism, the (child's) genome will be sequenced and doctors will compare it to the database to find out what form of autism that child has. With this information in hand they can then better inform the family of what to do, and equally important, what not to do," he told Reuters.
Although the database is still a long way off, I'm excited to learn more about my son Liam's genes. Since Liam has a diagnosis of "severe" autism, it could be very beneficial to compare his genes to others with a similar diagnosis, and see what sorts of abilities (not disabilities) he shares with them.
What are your thoughts on this latest research?
Jamie Pacton lives near Lake Michigan where she drinks loads of coffee, dreams of sailing, and enjoys each day with her husband and two sons, Liam (6) and Eliot (4). Her writing has appeared in the Autism and Asperger's Digest (2011-2013), Parents, and the book collection Monday Coffee and Other Stories of Parenting Kids with Special Needs. Find her at www.jamiepacton.com, Facebook (Jamie Pacton), and Twitter (@jamiepacton).
Image: Three cute funny children lying on the ground and looking at the camera via Shutterstock.