title: Ethnic differences in allelic associations of the interleukin-1 gene cluster in South African patients with inflammatory bowel disease (IBD) and in control individuals.
abstract: The allelic frequencies of TaqI, PstI, and variable number of tandem repeat (VNTR) polymorphisms of the IL-1beta, IL-1 receptor (IL-1Re), and IL-1 receptor antagonist (IL-1Ra) respectively, were investigated in black and white patients with inflammatory bowel diseases (IBD) and compared with control individuals. Plasma concentrations of IL-1beta and IL-1Ra were also determined in these individuals. The IL-1beta TaqI(-) allele was significantly more frequent in 50 white IBD patients (60%) compared with 47 white controls (17%), and 20 black patients (20%) (P=0.00001 and P=0.0001, respectively). The IL-1Re PstI(-) allele was significantly more frequent in 20 black patients (75%) compared with 50 white patients (44%) (P=0.0001). The frequency of the IL-1Ra 240-bp allele was lower in black (12%) compared with white controls (25%), (P=0.0151), and the 410-bp allele was more frequent in black (87%) compared with white (73%) controls (P=0.0096). Linkage disequilibrium was found in black individuals homozygous for the 410-bp allele of IL-1Ra, and the PstI(-) allele of IL-1Re (84%) (P=0.0032). There was a significantly increased level of IL-1Ra in black patients compared with white patients and black controls (P=0.0006 and P=0.0008, respectively). The population differences in allelic frequencies of the IL-1 gene cluster and IL-1Ra concentrations suggest that genetic and environmental factors play an important role in susceptibility to IBD.
authors.affiliation: Department of Medicine, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: O
authors.initials: O
authors.lastname: Mwantembe
authors.forename: M C
authors.initials: MC
authors.lastname: Gaillard
authors.forename: M
authors.initials: M
authors.lastname: Barkhuizen
authors.forename: V
authors.initials: V
authors.lastname: Pillay
authors.forename: S D
authors.initials: SD
authors.lastname: Berry
authors.forename: J B
authors.initials: JB
authors.lastname: Dewar
authors.forename: E
authors.initials: E
authors.lastname: Song
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American; D000483:Alleles; D044383:Black People; D016022:Case-Control Studies; D015252:Deoxyribonucleases, Type II Site-Specific; D005006:Ethnicity / Q000235:genetics*; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D006720:Homozygote; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000097:blood / Q000453:epidemiology / Q000235:genetics*; D007375:Interleukin-1 / Q000097:blood / Q000235:genetics*; D007438:Introns / Q000235:genetics; D015810:Linkage Disequilibrium / Q000235:genetics; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats / Q000235:genetics; D005810:Multigene Family / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D017472:Receptors, Interleukin-1 / Q000097:blood / Q000235:genetics*; D013019:South Africa / Q000453:epidemiology; D044465:White People; D000515:alpha 1-Antitrypsin / Q000032:analysis
chemical_list: D007375:Interleukin-1; D017472:Receptors, Interleukin-1; D000515:alpha 1-Antitrypsin; C024388:CTGCAG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific; C027046:TCGA-specific type II deoxyribonucleases