| Genotype | Inattentive type n (%) | Restrictive type n (%) | Combined type n (%) | Control | p-value |
| CC | 15 (30%) | 12 (24%) | 21 (21%) | 22 (22.2%) | 0.520 |
| CG | 21 (44%) | 25 (50%) | 61 (61%) | 52 (52.5%) | |
| GG | 14 (26%) | 13 (26%) | 19 (19%) | 25 (25.3%) | |
| Total | 50 | 50 | 100 | 99 |