Testing replication of a 5-SNP set for general cognitive ability in six population samples

Abstract

A 5-single nucleotide polymorphism (SNP) set has been associated with general cognitive ability in 5000 7-year-old children from the Twins Early Development Study (TEDS). Four of these SNPs were identified through a 10K microarray analysis and one was identified through a targeted analysis of brain-expressed genes. The present study tested this association with general cognitive ability in six population samples of varying size and age from Australia, the UK (Scotland and England) and the Netherlands. Results from the largest sample (N=1310) approached significance (P = 0.06) in the direction of the original finding, but results from the other samples (N = 205-758) were mixed. A meta-analysis of the results - allowing for effect size heterogeneity between samples - yielded a non-significant correlation (r = -0.01, P = 0.57), indicating that this SNP set was not associated with general cognitive ability in the populations studied.