Gene Defect Tied to Autism in Small Number of Cases

City of Hope researchers have identified a gene defect that may cause autism in a small percentage of cases.

The discovery provides new insight into how the debilitating disorder, which affects as many as one in 500 children, develops.

Dr. Steve Sommer, a molecular geneticist at the medical center in Duarte, reported in the current issue of the journal Molecular Psychiatry that 3% of 148 unrelated autism patients his team studied had a defect in a gene called neuroligin 4, or NLGN4. The defective gene was not found in any of 336 healthy patients.

NLGN4 plays a role in forming certain types of synapses, which are the communication connections between nerve cells. Higher thought processes depend on the formation of adequate numbers of synapses. An inadequate number may lead to the symptoms of autism, which include poor language skills and an inability to handle social relations.

The new results complement two recent French studies. In one, French researchers found a truncated form of the protein produced by NLGN4 in a boy with autism. In the second study, a team found a mutated form of the gene in a family in which several members had autism.

The research “provides rather compelling evidence that defective NLGN4 genes predispose individuals to autism,” Sommer said.