At age 2, nominal association was detected between the DAT1 3'UTR VNTR (χ2 = 7.00, df = 2, p = 0.03) and one NET1 SNP, rs11568324 (χ2 = 4.38, df = 1, p = 0.04) with the ADHD composite (Table 5). This evidence concerns the gene SLC6A3 and attention deficit-hyperactivity disorder.