Table 1. Some genetic associations with pooled risk elevation for ADHD (pooled odds ratio) that have been confirmed in meta-analyses*.
| Gene | Gene product | Variant / risk allele | Pooled odds ratio |
| DRD4_ | Sopamine D4_receptor | VNTR in exon 3/5-repeat allele | 1.33 |
| VNTR in exon 3/7-repeat allele | 1.68 | ||
| Polymorphism in promoter/T allele | 1.21 | ||
| DRD5 | Dopamine D5_receptor | Dinucleotide repeat/ 148-bp allele | 1.23 |
| DAT1_ | Dopamine _transporter | VNTR in exon 8/3-repeat allele | 1.25 |
| VNTR in 3-UTR/10-repeat allele | 1.17 | ||
| Polymorphism in 3’-UTR/G allele | 1.2 | ||
| 5HTT | Serotonin _transporter | 5HTTLPR/ long allele |
1.31 |
| HTR1B_ | Serotonin 1B _receptor | Polymorphism in exon 1/G allele | 1.11 |