In addition to the formal testing of ten SNPs for each phenotype Lasky-Su and coworkers also report a more exploratory analysis of all SNPs in the dataset. There were 58 association findings with P values smaller than 10−5, of which 46 SNPs were unique. Some SNPs showed association under more than one genetic model and/or across phenotypes. Although none of the SNPs listed here are genome-wide significantly associated with ADHD, a high percentage of the SNPs is present in brain-expressed genes and/or in linkage regions for ADHD and other psychiatric disorders (see Table 2). A particularly interesting finding from this set includes the SNP in NOS1, encoding the neuronal form of nitric oxide synthase. NO acts as the second messenger of the N-methyl-d-aspartate receptor and interacts with both the dopaminergic as well as the serotonergic system in the human brain. NOS1 has been associated with impulsive and aggressive behavior and ADHD (Reif et al. 2009). Association has also been noted with Alzheimer’s disease (Galimberti et al. 2008) and schizophrenia, as well as with related neuropsychological performance (Reif et al. 2006).Table
