Table 2.
Single nucleotide polymorphisms of components of the ECS studied in human IBD.
| Genotype | |||||
|---|---|---|---|---|---|
| FAAH C385A | CC | CA | AA | Associations | |
| Storr 2008 | CD [n = 202] | 67.3% | 31.2% | 1.5% | No differences in prevalence between groups. Phenotype not assessed in this study |
| Controls [n = 206] | 63.6% | 35.0% | 1.5% | ||
| Storr 2009 | CD [n = 435] | 65.8% | 30.1% | 4.1% | No differences in prevalence between groups. AA associated with more EIMs and penetrating phenotype in CD; earlier age of onset in UC. |
| UC [n = 167] | 65.3% | 32.9% | 1.8% | ||
| Controls [n = 406] | 61.6% | 34.5% | 3.9% | ||
| CNR1 G1359A | GG | GA | AA | ||
| Storr 2010 | CD [n = 216] | 53.3% | 39.8% | 6.9% | Lower prevalence of AA in UC versus controls. AA associated with lower body mass index and later age of onset of CD. |
| UC [n = 166] | 58.4% | 38.0% | 3.6% | ||
| Controls [n = 197] | 52.3% | 37.0% | 10.7% | ||
| CNR2 Q63R | QR | RR | |||
| Yonal 2014 | CD [n = 101] | 10.9% | 38.6% | 50.5% | No differences in prevalence or phenotype in this study. |
| UC [n = 101] | 6.9% | 43.6% | 49.5% | ||
| Controls [n = 101] | 11.9% | 37.6% | 50.5% | ||
| Striscuglui 2016 | CD [n = 112] | 2.7% | 48.2% | 49.1% | Paediatric cohort. RR genotype more prevalent in IBD than controls and associated with more severe disease activity at diagnosis. In UC, associated with higher risk of relapse. |
| UC [n = 105] | 18.1% | 38.1% | 43.8% | ||
| Controls [n = 600] | 16.0% | 51.7% | 32.3% | ||
Prevalence of genotypes are displayed alongside associations with disease phenotype. Data extracted from references 45–49.
IBD, inflammatory bowel disease; CD, Crohn’s disease; UC, ulcerative colitis; ECS, endocannabinoid system; EIM, extra-intestinal manifestations.