No association between dopamine D2 receptor gene (DRD2) and human intelligence

Abstract

Significantly diminished intellectual functioning, as indicated by appropriately administered IQ tests with scores below 70, is a frequent mental handicap leading to severe social disadvantages and serves as a paradigm for molecular genetic research of complex disorders and traits due to its multitude of known and unknown, genetic as well as environmental causes. Since the number of confounding variables is expected to be considerably reduced in the normal population at the opposite ends of the IQ distribution, we employed a contrast of extremes approach by comparing adults of high (N = 71) and average IQ (N = 78) in association studies to search for genes involved in the multigenic forms of familial mental retardation. The dopamine D2 receptor gene (DRD2) was chosen as a candidate gene for general cognitive ability (g) since it has been found to be associated with visuospatial ability which in turn is highly correlated with g. Confirming two similar studies in children, however, no significant differences were obtained. Given three negative studies, the DRD2 gene is unlikely to pay a major role in g.

Association Between Polymorphisms of the Dopamine Receptor D2 and Catechol-o-Methyl Transferase Genes and Cognitive Function

“…In previous studies, DRD2 rs1800497 was found to not be associated with intelligence in middle-aged adults (Moises et al 2001), whereas it was associated with increased IQ in a study of young women (Tsai et al 2002). The A1(T) (Welton et al 2008) allele was associated with better performance in immediate and delayed memory and MMSE in a population with age-related cognitive impairment (Bartres-Faz et al 2002).…”

Partisanship, Voting, and the Dopamine D2 Receptor Gene

“…However, results based on the DRD2 gene are mixed. An early study linked the A1 allele to reduced cognitive ability (Berman and Noble 1995) but subsequent work has failed to corroborate these findings (Moises 2001, Petrill 1997. Studies of nonhuman subjects have shown activation of D2 receptors improves acquisition and retention of working memory tasks (Missale et al 1998).…”

The quest for quantitative trait loci associated with intelligence

“…Ball et al, 1998;Moises et al, 2001); glutamate receptor-modulating synaptic glutamate (GRM3; Egan et al, 2004); serotonin receptor 2A (HTR2A; Moises et al, 2001); serotonin transporter (SLC6A4; Payton et al, 2005) and nicastrin (NCSTN; Deary et al, 2005).…”