Ethnic differences in genetic polymorphism associated with irritable bowel syndrome

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]

¹Irritable 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.