But that is not what investigators, including Robert Ring
, discovered when they peered at the DNA of autistic families using high-tech genetic sequencing technology.
"You might predict ahead of time that if you have autism affecting more than one child, you would see similarities in the genetic predisposition for that between the children," he
We actually see something very different."
Ring, of the advocacy group Autism Speaks, says researchers found that in almost 70 percent of cases in which two siblings developed autism, lightning essentially struck twice.
says each pattern of differences has its own clinical manifestations and behaviors.
"We frequently refer to these differences as the same differences you might see in snowflakes," said Ring
"Every snowflake is different when you take a really close look at it.
And indeed, as you look from one child to another child, the same unique differences are present there."
says the findings strongly suggest that there are influences beyond genetic inheritance that play a role in the development of autism and the form it takes.
"This study definitely shows that in a family where two siblings have autism and they are genetically very similar but still different, we are seeing very different mutations in most cases behind that autism," he
said this type of work will continue to grow.
"Hopefully in the next few years will be able to have a much clearer idea of the different sub-types of autism that can be explained through the lens of genetics," he
says a full assessment of each child's genome can inform educators and therapists about the best way to personalize treatment for kids with autism.