stimuli (Iakoubova et al. 2008b; Iakoubova et al. 2008a; Shiffman et al. 2008). In the referenced studies, a coding variant in KIF6 altered the response to statins in cardiovascular disease. The gene’s role in moderating the influence of mother’s warmth on ADHD severity will have to be investigated in further detail. An additional six interaction associations at P values of 10−4 were observed in the absence of genetic main effects (Table V in Sonuga-Barke et al. 2008). Interestingly, all but one finding were observed under a recessive genetic model, which strongly limited the number of informative families. Of these associations, only one was for mother’s warmth. This finding falls into the BCAS1 gene on chromosome 20, which is a potential oncogene with high expression in brain. Of the five association findings interacting with mother’s criticism, especially a finding on chromosome 2 is interesting, as it falls into the MTA3 gene, which has two additional SNPs associated with ADHD in the GWAS for quantitative phenotypes (Lasky-Su et al. 2008b). The authors also tested potential G × E effects for the list of ADHD candidate genes defined earlier (Brookes et al. 2006). Interaction association P values are most significant for DDC (mother’s
