A gene variant that affects thinking and learning performance may protect the memory and intellectual capacity of older people, according to a study in the journal Neurology.
Researchers from the University of California in San Francisco focused on the gene encoding the enzyme catechol-O-methyltransferase (COMT), which regulates the level of dopamine in the brain – a neurotransmitter involved, among others in the processes of remembering and learning.
The study was conducted for 8 years in a group of 2.858 elderly white and black people. At the beginning of the experiment, everyone was to perform two tests: one to assess concentration and memory, and the other to assess reaction speed and the ability to judge objects and places. The tests were then repeated after 3, 5 and 8 years.
Genetic analyzes were also performed to see which of the two COMT variants each tested person had. They code enzymes that differ from each other in only one amino acid. The active form, containing the amino acid valine, quickly degrades dopamine in the brain, while the other one, containing methionine, is four times less active, which means that the concentration of this neurotransmitter is constantly high in the brain.
It turned out that the initial mental performance of the respondents was not related to the COMT variant. However, over time, holders of the methionine variant had their memory and other intellectual abilities deteriorated at a faster rate than those of holders of the valine variant. Ultimately, owners of the more favorable version of the gene scored better on tests than those who did not.
According to the author of the study, Dr. Alexandra Fiocco, these results are somewhat surprising as it has previously been shown that the valine variant has a less favorable effect on thinking ability in young people.
The researcher believes that a better understanding of the relationship between COMT variants and intellectual performance could help in the development of new drugs to reduce dementia in old age. (PAP)