Table 2.
Association of SNPs and VNTRs with cannabis use. Genotype and allele frequency analyses.
| SNP ID (gene) | Genotypes and Alleles | Subjects | Fisher’s exact test | SNP ID / VNTR (gene) | Genotypes and Alleles | Subjects | Fisher’s exact test | |||
| CTRLs | MJ users | CTRLs | MJ users | |||||||
| rs1049353 (CNR1) | GG | 61.8% | 52.17% | 0.051(*) | rs6277 (DRD2) | CC | 11.83% | 16% | 0.51 | |
| AA | 4.30% | 0.00% | TT | 29.03% | 33% | |||||
| GA | 38.20% | 47.83% | CT | 59.14% | 51% | |||||
| G allele | 80.90% | 76.09% | 0.3 | C allele | 41.40% | 41.85% | 1 | |||
| A allele | 19.10% | 23.91% | T allele | 58.60% | 58.15% | |||||
|
rs324420 (FAAH) |
CC | 62.37% | 68.48% | 0.52 |
rs1800497 (ANKK1) |
CC | 76.34% | 57.61% | 0.034 | |
| AA | 6.45% | 3.26% | TT | 2.15% | 4.35% | |||||
| CA | 31.18% | 28.26% | TC | 21.51% | 38.04% | |||||
| C allele | 77.96% | 82.61% | 0.29 | C allele | 87.10% | 76.63% | 0.032 | |||
| A allele | 22.04% | 17.39% | T allele | 12.90% | 23.37% | |||||
|
rs4680 (COMT) |
GG | 33.33% | 31.52% | 0.97 |
VNTR 3’UTR (DAT1) |
9R/9R | 10.75% | 7.61% | 0.81 | |
| AA | 16.13% | 16.30% | 10R/10R | 43.01% | 44.57% | |||||
| GA | 50.54% | 52.17% | 9R/10R | 43.01% | 43.48% | |||||
| G allele | 58.60% | 57.61% | 0.91 | 9R | 65.57% | 67.78% | 0.73 | |||
| A allele | 41.40% | 42.39% | 10R | 34.43% | 32.22% | |||||
| VNTR-48 bp (DRD4) | R<7 (S) | 84.41% | 88.04% | 0.36 (**) | ||||||
| R≥7 (L) | 15.59% | 11.96% | ||||||||
(*)
Due to the lack of a reasonable number of homozygous A/A subjects, for the SNP rs1049353, Fisher’s exact test was performed in two different ways, including and excluding A/A homozygous subjects (no significant differences were revealed excluding A/A subjects).
(**)
For DRD4 VNTR, since the high number of alleles, the number of observations does not allow the statistical analysis for the genotype distribution; in this case statistical analysis is reported only on alleles.