A gene that is the basis for healthy information processing has been identified by an international team of researchers. The discovery is an important step on the long road to understanding cognitive aging and age-related diseases, such as Alzheimer’s disease.
The study is one of the the largest genetics study yet to associate a specific genetic mutation with information processing speed. Senior scientist on the study Dr. Tom Mosley, of the University of Mississippi Medical Center (UMMC), said:
“It is well known that genetic variation plays an important role in explaining individual differences in thinking skills such as memory and information processing speed. However, the genes that underlie thinking skills remain largely unknown. Our team has identified a genetic mutation that may help unravel this puzzle.“
Earlier studies in families and in twins have shown genetics play a big role in cognitive functioning. But finding the specific genes or genetic regions has proven difficult, requiring a combination of large sample sizes and detailed genetic measurements.
In this case, researchers analyzed data from more than 30,000 people who were 45 or older, bringing together genetic and cognitive functioning data from participants in several studies in 12 different countries.
Information Processing Speed
In addition, they examined genetic variations across 2.5 million sites along each individual’s DNA, looking for associations between genetic variants and performance on several different tests of cognitive function.
Of the different cognitive skills examined, the strongest genetic association was related to performance on a test of information processing speed. The most associated variants were located in the CADM2 gene, also known as Syncam2.
Lead author Dr. Carla Ibrahim-Verbaas, a resident in neurology at Erasmus University Medical Center, said:
“It seems like, through this genetic analysis, we have identified a genetic variant which partly explains the differences in information processing speed between people. It confirms the likely role of CADM2 in between-cell communication, and therefore cognitive performance. It is of interest that the gene has also been suggested in other studies to be involved in autism and personality traits.“
The results still need to be replicated by additional studies for verification.
Frontal and Cingulate Cortex
Researchers said a protein product from CADM2 is involved in the short-term and long-term chemically mediated communication between brain cells and is specifically abundant in the frontal and cingulate cortex, which are areas of the brain known to be involved in processing speed as well as in the developing brain.
“We are finding that for complex traits, like cognitive function, not a single gene, but several genes or genetic regions come into play, with each making a relatively small contribution,” Mosley said. “We now have the technology to measure across the entire genome in a much more fine-grained manner compared to a few years ago, in this case 2.5 million sites, and are able to combine that genetic mapping with large sample sizes. The collaboration of leading scientists from around the world, who have agreed to pool their data and analytic resources, is significantly enhancing our ability to identify genes related to complex brain functions and disease.“
T H Mosley, et al GWAS for executive function and processing speed suggests involvement of the CADM2 gene Molecular Psychiatry , (14 April 2015) | doi:10.1038/mp.2015.37
Illustration: Bill McConkey, Wellcome Images Creative Commons by-nc-nd 4.0