Table 3. Associations between IIU and the TNFA-308 and TNFA-238 loci are most compatible with an additive (allelic model).
| Locus |
IIU patients |
Healthy controls |
X2 |
Degrees of freedom |
p value |
pc value |
Odds ratio for minor allele (95% CI) |
|---|---|---|---|---|---|---|---|
| TNFA −308 (rs1800629) | |||||||
| Genotype frequency AA/AG/GG |
3/24/17 |
2/24/66 |
13.84 |
2 |
0.001 |
0.019 |
- |
| Allele frequency A/G | 30/58 | 28/156 | 12.64 | 1 | 0.00038 | 0.0042 | 2.9 (1.6–5.2) |
| TNFA −238 (rs361525) | |||||||
|---|---|---|---|---|---|---|---|
| Genotype frequency AA/AG/GG |
0/16/28 |
1/6/85 |
18.36 |
2 |
<0.0010 |
<0.019 |
- |
| Allele frequency A/G | 16/72 | 8/176 | 14.16 | 1 | 0.00017 | 0.0019 | 4.9 (2.0–11.9) |
Modeling the genetic association revealed an underlying allelic (additive) model with the minor alleles, TNFA-308A and TNFA-238A, associated with disease. Dominant and recessive models were not significant. Statistical analyses of genetic model used the Pearson X2 test with 2-tailed probability values in PLINK with Bonferroni correction for the number of loci (n=19). Genotype associations were determined using the Fisher exact test in SPSS with Bonferroni correction (n=19). Odds ratios were calculated in Open Epi. Abbreviations: p value, uncorrected probability value; pc, Bonferroni corrected p value (pc=p x11); X2, Chi-square test; CI, confidence intervals.