A recent genome wide scan of 958 ADHD child-parent trios reported that 2 single nucleotide polymorphisms (SNPs) in the IL-16 gene were associated with the inattentive phenotype, and a second analysis of 930 patients described a nominal association for IL-3 (NFIL3: C allele) with an earlier onset of the disorder [33,34]. Here, IL16 is linked to attention deficit-hyperactivity disorder.