The human genome can have some quirky features, like copy number variation (CNV). When this happens, an individual may lose, or carry extra stretches of DNA sequence that can range from just a few bases to huge regions, some of which may contain entire genes. CNVs have also been linked to some human diseases. Scientists have now learned more about how CNVs can influence human cognition. After analyzing CNVs in almost 260,000 people, the investigators revealed more about how CNVs may impact cognitive ability, the brain, and some other tissues, and created a kind of CNV reference map. The findings have been reported in Cell Genomics.
Many CNVs have insignificant impacts, because the regions that are deleted or duplicated are not particularly important. But some CNVs are related to genetic diseases. This study identified some deletions that can occur in the subcortical region of the brain and which disrupt cognition.
In other cases, some duplications were found that affect the cortex, and the study also revealed duplications that may help shield against neurodegeneration. Elderly carriers of some duplications were found to have a lower risk of cognitive decline. “We have observed the first genetic duplication that could prevent cognitive decline,” said study co-author Guillaume Huguet, a Université de Montréal graduate student.
The research also suggested that CNVs that occur in genes that are expressed in tissues other than the brain may still influence cognitive function. This may help explain comorbidities in which individuals with intellectual disabilities also have disorders affecting various tissues and organs other than the brain.
The scientists are hopeful that this work will not only improve the treatment of some disorders, but will contribute to a more comprehensive approach to therapeutics; patients with cognitive diseases would benefit from care that considers their whole body.
The study has shown how clinicians can take CNVs into account when evaluating a patient, and has provided some information on how neurodevelopmental disorders like autism may be affected by a patient's CNVs. Carriers of certain deleterious CNVs could be identified, and clinicians might anticipate potential complications, and adjust treatments accordingly for a specific patient's needs.
“This allows clinicians to better adapt their diagnostics using genetic data as a starting point,” said Huguet.
More research will be needed to understand the impact of CNVs, but this research has shown how CNV maps can improve clinical care.
Sources: University of Montreal, Cell Genomics