Meta-analysis of the association of the SLC6A3 3′-UTR VNTR with cognition

The gene coding for the dopamine transporter (DAT), SLC6A3, contains a 40-base pair variable number of tandem repeats (VNTR) polymorphism (rs28363170) in its 3′ untranslated region. This VNTR has been associated with attention deficit hyperactivity disorder (ADHD) and has been investigated in relation to cognition and brain function. Here, we report the results of a comprehensive meta-analysis with meta-regression examining the association of the VNTR with different domains of cognition in healthy adults. We extracted data from 28 independent studies and carried out meta-analyses for associations with working memory (k = 10 samples, N = 1193 subjects), inhibition (k = 8 samples, N = 829 subjects), executive functions including inhibition (k = 10 samples, N = 984 subjects), attention (k = 6 samples, N = 742 subjects) and declarative long-term memory (k = 5 samples, N = 251 subjects). None of the investigated dimensions showed significant associations with the VNTR (all p > 0.26). Meta-regression including year of publication, gender, age, ethnicity and percentage of 10R-homozygotes similarly did not attain significance. We conclude that there is no evidence that rs28363170 may be a significant predictor of cognitive function in healthy adults.