Functional gene group analysis indicates no role for heterotrimeric G proteins in cognitive ability.

Previous functional gene group analyses implicated common single nucleotide polymorphisms (SNPs) in heterotrimeric G protein coding genes as being associated with differences in human intelligence. Here, we sought to replicate this finding using five independent cohorts of older adults including current IQ and childhood IQ, and using both gene- and SNP-based analytic strategies. No significant associations were found between variation in heterotrimeric G protein genes and intelligence in any cohort at either of the two time points.

Apolipoprotein E genotype does not predict decline in intelligence in healthy older adults.

There is evidence of a genetic influence on the decline in cognitive performance of older adults, although the mechanisms responsible are unknown. A group of 767 subjects of the Manchester University Age and Cognitive Performance longitudinal study volunteer group, followed up from 1985 to the present, were genotyped for apolipoprotein E (APOE). The data from this were related to cross-sectional and longitudinal trends in the Heim intelligence test score (AH4-1) using previously reported random-effects models (Neuropsychologia 39 (2001) 532).