Dopamine receptor and transporter (DAT1) polymorphisms
| Locus | Chromosomal region | Polymorphism |
| DAT1 | 5p15.3 | 40 bp tandem repeat polymorphism at the 3′ untranslated region16 |
| D1 (D1.1) | 5p31-34 | DdeI RFLP in the 5′ untranslated region of the gene17 |
| D1 (D1.8) | 5p31-34 | PvuI RFLP within codon 42117 |
| D2 | 11q22-23 | Microsatellite repeat at the 2nd intron18 |
| D2 | 11q22-23 | TaqI A RFLP 3′ flanking region of the gene18 |
| D2 | 11q22-23 | TaqI B RFLP within the first intron18 |
| D2 | 11q22-23 | BstNI RFLP from the -141C Ins/Del within the promoter region19 |
| D3 | 3q13.3 | MscI RFLP within the first exon20 |
| D4 | 11p | 48 bp repeat polymorphism at the third exon21 |
| D5 | 4p15.1-15.3 | Microsatellite (CT/GT/GA)n22 |