Several types of genetic alterations that affect mitochondria increase the risk of autism, two new studies suggest.
In one study, researchers examined the link between autism and each of 12 mitochondrial haplogroups, a collection of groups of genes inherited from one of the child’s parents that reflect DNA changes in an ancestor deep in the past. People with any of eight select haplogroups are almost twice as likely to be diagnosed with autism compared with those carrying the most common haplogroup, the study revealed. Because this type of mitochondrial variation is so common, it is likely to play a significant role in autism, says lead researcher Douglas Wallace, PhD, Director of the Center for Mitochondrial and Epigenomic Medicine at Children’s Hospital of Philadelphia.
A second study, published February in Behavior and Brain Function, shows that people with autism have more deletions in their mitochondrial DNA than people not diagnosed with autism. These deletions are present in only some of the mitochondria in each cell.
Together, the studies hint that mitochondria play an important role in autism.