Gene–pesticide interactions with NOS1 rs2682826 were first described in a study of 169 families; the authors report a positive association between ever pesticide use (in the home, garden, or work) among those with the homozygous wild-type genotype (OR = 3.52; 95% CI: 1.87, 6.95), but no association between pesticide use and PD in those with a variant allele (Hancock et al. 2008). This evidence concerns the gene NOS1 and Parkinson disease.