Scientists have uncovered what they say could be important new genetics clues about autism.
In a set of three papers being published in Thursday’s issue of the journal Neuron, researchers at the Cold Spring Harbor Laboratory, Yale University and Columbia University report provocative results from analyses of the genes from about 1,000 families. They hope the findings can lead to important insights into what causes the disorder and possibly better treatments.
Autism can be a devastating condition marked by difficulties interpreting common social cues and interacting with other people.
Two of the teams of researchers searched for so-called copy number variants -- duplications or deletions in one or more portions of DNA -- in the genes of members of families in which one child was diagnosed with autism but another was not. The researchers compared the DNA from siblings with and without the condition.
Michael Wigler and his colleagues at Cold Spring found more new mutations--those not inherited from parents--in the children with autism than in their siblings who did not have the condition. They identified at least 250 to 300 variations that appeared to be associated with the condition. The mutations appeared much more likely to cause autism in males than in females. That makes sense since boys are much more likely to get autism than are girls. But it raises questions about whether the mutations may cause other conditions in females, perhaps later in life, the researchers say. Females are more prone to other conditions, such as the eating disorders anorexia., the researchers noted.
An analysis of the mutations conducted by Dennis Vitkup of Columbia and colleagues indicate that at least some of the mutations occur in genes that play a role in normal brain development, including the development of structures known as “synapses.” Synapses are the junctions between brain cells that enable neurons to communicate with one another.
The third analysis, led by by Matthew State of Yale and colleagues, group found an association between mutations and autism that, when deleted, also play a role in Williams syndrome, a rare developmental disorder. People with that condition tend to be highly social, sensitive and empathetic. In contrast, people with autism have difficulty interpreting social cues and interacting with others.
“This relatively small genomic interval clearly holds important clues to understanding the social brain,” State said in a statement.
But given the large number of genetic variations that the analyses have identified, the findings indicate that the condition is extremely complicated, the researcher said.
“The diversity implies that a treatment for one form of autism may have no value for the majority,” Wigler said.
In a fourth paper accompanying the research, Christian Schaaf of the Baylor College of Medicine said the findings were part of a “very exciting time for autism research,” which is “poised to move on” to finally unravel the mysterious condition.