Table 1.
Ethnic characteristics of irritable bowel syndrome-risk genes based on published evidences
| Genetic model | IBS-risk genotype | IBS subtype | Country | Ethnic or demographic group | Research type | Ethnic characteristics | Ref. |
| 5-HT2A receptor | A homozygote in −1438G/A and C homozygote in +102T/C | IBS | Turkey and Greece | Western Asian/Caucasian | Case-control | Consistent in −1438G/A; inconsistent in +102T/C | [23,24] |
| 5-HT3A receptor | c.−42C>T | IBS-D | United States and China | Caucasian/Asian | Case-control; Meta-analysis | Inconsistent | [30,31,34] |
| 5-HT3E receptor | c.*76G>A in female | IBS-D | United Kingdom, Germany, China | Caucasian/Asian | Case-control; Meta-analysis | Consistent | [32-34] |
| 5-HT4 receptor | c.*61 T>C | IBS-D | United States, Germany, Belgium, Sweden | Only Caucasian | Case-control | NA | [37] |
| 5HTTLPR | S/S in short (S) or long (L) allele | IBS-C IBS-D IBS-M | United States, Greece, Italy, Germany, Turkey, China, Japan, South Korea, India, and Iran | NA | Case-control; Meta-analysis | Inconsistent | [40-43] |
| α2A-adrenergic receptor | −1291C/G | IBS-C | United States, Turkey, India, South Korea | Caucasian/Asian | Case-control | Inconsistent | [45-48] |
| GNB3 | T homozygote in 825C/T | IBS-C | United States, Greece, Netherlands, South Korea, China | Caucasian/Asian | Case-control; Meta-analysis | Inconsistent | [49-54] |
| SCN5A | Missense mutations1 | IBS-C IBS-D | United States, Sweden, Italy, Greece | Hispanic/Caucasian/Asian/American Indian/African American | GWA study; Case-control | Consistent | [61-63] |
| CNR1 | (AAT)n > 10 homozygote | IBS | South Korea, China, United States | Asian/Caucasian | Case-control | Inconsistent | [67-69] |
| FAAH | allele carriers in +385C/A | IBS | United States and China | Caucasian/Asian | Case-control | Inconsistent | [68,70] |
| CCK-1 receptor | 779T>C | IBS-C | United States and South Korea | Caucasian/Asian | Case-control | Consistent | [71,72] |
| IL-6 | rs1800795 (−174C/G) | IBS | Iran, India, United Kingdom, United States, Belgium, Sweden | Asian/Caucasian | Case-control; Meta-analysis | Inconsistent | [75-77] |
| IL-8 | rs2227306 (+781C/T) | IBS | Mexico, United Kingdom, United States | Indo-European/ Caucasian | Case-control; Meta-analysis | Inconsistent | [77-79] |
| IL-10 | G allele carriers in −1082A/G; C allele carriers in −592A/C | IBS | United States, United Kingdom, Netherlands, Mexico, Iran, China, South Korea, India | Caucasian/Asian | Meta-analysis | Inconsistent | [81] |
| TNF-α | GA heterozygote in −308G/A | IBS | Netherlands, United Kingdom, South Korea | Caucasian/Asian | Case-control | Inconsistent | [50,82-85] |
| TNFSF | rs4263839 G | IBS-C | United States and Sweden | Only Caucasian | Case-control | NA | [86] |
| TNFSF | rs6478108, rs6478109, rs7848647 | IBS-D | United Kingdom | Only Caucasian | Case-control | NA | [85] |
1
Irritable bowel syndrome-related SCN5A missense mutations including R225W, R433C, R986Q, G1037V, S1700G, and F1293S. IBS: Irritable bowel syndrome; 5-HT: 5-hydroxytryptamine; 5HTTLPR: 5-HT transporter length polymorphic region; GNB3: G-protein β3 subunit gene; FAAH: Fatty acid amide hydrolase; CCK: Cholecystokinin; IL: Interleukin; TNF: Tumor necrosis factor; TNFSF: TNF superfamily; NA: Not applicable.