We investigated the role of a single nucleotide polymorphism rs3764030 (G > A) within the human GRIN2B promoter in mental processing speed in healthy, cognitively intact, older adults. In vitro DNA-binding and reporter gene assays of different allele combinations in transfected cells showed that the A allele was a gain-of-function variant associated with increasing GRIN2B mRNA levels. We tested the hypothesis that individuals with A allele will have better memory performance (i.e. faster reaction times) in older age. Twenty-eight older adults (ages 65-86) from a well-characterized longitudinal cohort were recruited and performed a modified delayed match-to-sample task. The rs3764030 polymorphism was genotyped and participants were grouped based on the presence of the A allele into GG and AA/AG. Carriers of the A allele maintained their speed of memory retrieval over age compared to GG carriers (p = 0.026 slope of the regression line between AA and AG versus GG groups). To validate the results, 12 older adults from the same cohort participated in a different version of the short-term memory task. Reaction times were significantly slower with age in older adults with G allele (p < 0.001). These findings support a role for rs3764030 in maintaining faster mental processing speed over aging.
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This work was founded by National Institute on Aging K01AG000986; P30AG028383; Virginia Center on Aging (RHL), Inova Research Foundation, GeorgeMason Research Foundation, (RHL, ML).
Jiang, Yang; Lin, Ming Kuan; Jicha, Gregory A.; Ding, Xiuhua; McIlwrath, Sabrina L.; Fardo, David W.; Broster, Lucas S.; Schmitt, Frederick A.; Kryscio, Richard J.; and Lipsky, Robert H., "Functional Human GRIN2B Promoter Polymorphism and Variation of Mental Processing Speed in Older Adults" (2017). Behavioral Science Faculty Publications. 28.