A study conducted at the Centre hospitalier universitaire Sainte-Justine shows that intellectual disability may be caused by non-hereditary genetic issues.

Researchers found a group of mutations in genes that are associated with brain activity that cause intellectual disabilities. However, specific genes involved in this process are currently unknown.

The team of researchers studied 197 synaptic genes and identified mutations that cause intellectual disabilities in 10 of the 95 participants.

They indicated that some intellectual disabilities are associated with physical abnormalities that reveal major genetic abnormalities. However, in some cases disabilities are not linked with obvious physical traits. Researchers found that all mutations affect communication between nerve cells, which they believe is the cause found in nearly 66 percent of individuals who have the disorder.

"The group of genes we identified all play important roles in nerve synapses, the structures that allow brain cells to rapidly transfer information," said Dr. Jacques Michaud, senior author of the study. "These findings indicate that, in this case, intellectual disability occurs because there is a disruption in nerve cell communication."