Good Entropy

From Mounting evidence links language pathway to autism

FOXP2 codes for a protein that regulates the expression of other genes. Last year, an international group of scientists identified one of its targets, contactin-associated protein-like 2 (CNTNAP2). They also found that certain common variants of CNTNAP2 tend to crop up in people with specific language impairment, a developmental disorder.

CNTNAP2 was an exciting find because three independent teams had recently published that common variants of the gene up the risk of developing autism.

“I think the evidence now that CNTNAP2 is involved [in autism] is quite good,” says leader of one of the teams, Aravinda Chakravarti, professor at the McKusick Nathans Institute of Genetic Medicine at Johns Hopkins University. “We’re now interested in finding the molecular basis of this.”

In unpublished data, Chakravarti says he’s found that CNTNAP2 is over-expressed in a small number of postmortem autistic brains.

Geneticists have discovered many different autism-related variants of CNTNAP2, a massive gene spanning 2.3 million base pairs. “Disruptions in the front end of the gene [usually] mean you’ll get a more severe disorder, like full-blown autism or severe expressive language delay,” notes Martin Poot, research associate professor of medical genetics at the University Medical Center Utrecht, in the Netherlands.