No significant differences were determined between the ADHD and control groups in terms of rs2268493, rs13316193, and rs53576 genotype distribution (P = 0.078, P = 0.330, and P = 0.149, respectively).
Although there was no association with the ADHD phenotype, an association with social cognitive impairments in a subset of the ADHD probands (N=112) was found for SNP rs53576 (F=5.24, p=0.007) with post-hoc tests demonstrating that the AA genotype was associated with better social ability compared to the AG genotype.
Unexpectedly, the two most frequently studied OXTR SNPs in the general population (rs53576 and rs2254298) were associated with an increased severity of social deficits in ASD (p < 0.0001 and p = 0.0005), yet fewer social deficits in ADHD (p = 0.007 and p < 0.0001).