Table 2.
Differences in Fatigue by Polymorphisms of TPH1, TPH2, SERT, and COMT Genes in Women with Irritable Bowel Syndrome.
| Genotype | Fatiguea | p b | p c |
|---|---|---|---|
| TPH1 (rs4537731) | .857 | .806 | |
| AA (n = 72) | 37.8 (28.0) | ||
| AG (n = 91) | 35.5 (23.8) | ||
| GG (n = 22) | 36.1 (28.3) | ||
| TPH1 (rs684302) | .538 | .833 | |
| CC (n = 59) | 34.6 (26.1) | ||
| CT (n = 94) | 36.1 (25.3) | ||
| TT (n = 32) | 40.9 (27.7) | ||
| TPH1 (rs211105) | .051 | .060 | |
| TT (n = 109) | 40.2 (27.3) | ||
| GT (n =70) | 30.6 (22.8) | ||
| GG (n = 6) | 39.5 (27.1) | ||
| TPH1 (rs1800532) | .525 | .923 | |
| CC (n = 63) | 34.9 (26.0) | ||
| AC (n = 91) | 35.9 (25.2) | ||
| AA (n = 31) | 41.2 (28.1) | ||
| TPH2 (rs4570625)d | .005* | <.001* | |
| GG (n = 115) | 31.7 (24.8) | ||
| GT (n = 61) | 43.6 (27.4) | ||
| TT (n = 9) | 48.9 (14.8) | ||
| SERT (rs25531)e | .341 | .422 | |
| s/s (n = 36) | 38.7 (28.3) | ||
| s/l (n = 84) | 36.9 (25.3) | ||
| l/l (n = 64) | 30.9 (22.6) | ||
| COMT (rs4680) | .434 | .286 | |
| Val/Val (n = 43) | 33.6 (25.8) | ||
| Val/Met (n = 93) | 35.7 (26.9) | ||
| Met/Met (n = 49) | 40.4 (24.3) |
Note. N = 185. Data are presented as mean (SD). All comparisons controlled for age. COMT = catechol-O-methyltransferase; SERT = serotonin transporter; TPH = tryptophan hydroxylase.aPercentage of days with moderate to very severe fatigue with a daily diary for 28 days. bTesting differences in fatigue by genotype. cTesting differences in fatigue by genotype, controlling for percentage of days with moderate to very severe abdominal pain, depression, anxiety, feeling stressed, and sleepiness during the day. dPairwise group comparisons among genotypes: GG ≠ GT p = .004, GG ≠ TT p = .002, GT = TT p = .604. e N = 184 due to missing genetic data.