Val Allele Linked to Protective Effect on Cognitive Function

Effect of the catechol-O-methyltransferase variant is observed in older adults

MONDAY, April 19 (HealthDay News) -- In older adults, the Val variant of the catechol-O-methyltransferase (COMT) gene is associated with a protective effect on cognitive function, according to research published in the April 20 issue of Neurology.

Alexandra J. Fiocco, Ph.D., of the University of California in San Francisco, and colleagues analyzed data from 2,858 black and white men and women aged 70 to 79 and free of dementia at recruitment. Participants' DNA was analyzed for the COMT gene; the COMT enzyme catalyzes the degradation of dopamine and is involved in cognitive function.

The researchers found that COMT genotype was not associated with baseline cognitive function using the Modified Mini-Mental State Examination or the Digit Symbol Substitution Test. However, they found that the Met variant of the COMT gene was linked to a greater cognitive decline over eight years of follow-up, and that the Val variant had a protective effect on cognition.

"Altogether, the present findings suggest COMT genotype is associated with change in global and executive cognitive function over an eight-year period in a biracial cohort of elderly men and women. We report an association between the Val allele and maintenance of cognitive function in black and white elders. Additional studies are needed to confirm the negative impact of the Met allele on cognitive decline in late life," the authors conclude.

A co-author disclosed financial ties to the pharmaceutical industry.

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