IL-1 receptor antagonist (IL-1Ra) gene polymorphism in patients with inflammatory bowel disease in India.
OBJECTIVE
An association between polymorphism in the gene coding for the anti-inflammatory cytokine interleukin-1-receptor antagonist (IL-1Ra) and ulcerative colitis (UC) has been reported. To date, there is no report from India confirming this association. In the present study the aim was to assess the allele frequencies and carriage rates of different alleles of 86 bp (base pair) variable number tandem repeat (VNTR) in intron 2 of the IL-1Ra gene in patients with inflammatory bowel disease (IBD) and healthy controls from northern India.


METHODS
Eighty-two patients with UC, 21 with Crohn's disease (CD) and 141 ethnically matched controls were enrolled in this study. Genotyping was done using a polymerase chain reaction (PCR) amplification of the intron-2 fragment harboring a VNTR nucleotide sequence. The PCR products were separated on 2% agarose gel. Statistical analysis was performed using the chi-squared (chi(2)) test.


RESULTS
The frequencies of allele 2 in UC, CD and healthy controls were 26%, 50% and 24%, respectively. The frequency of allele 2 in CD was higher than that in UC (p = 0.002; OR = 2.9) and healthy controls (p = 0.001; OR = 3.1; 95% CI = 1.5-6.3). Alleles 3 and 4 were absent in patients with CD, while allele 5 was absent in all three groups.


CONCLUSIONS
The present study demonstrated an association between allele 2 and patients with CD but not with UC. Interestingly, the allele frequency and carriage rates of allele 2 were significantly higher in patients with CD than in patients with UC and in healthy subjects. Ethnic differences, genetic heterogeneity and sample size could be the reasons for such differences in comparison with studies from the West.
Mittal
Rama D
RD
Department of Urology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India. rmittal@sgpgi.ac.in/ramamittal@yahoo.com
Bid
Hemant K
HK
Ghoshal
Uday C
UC
D000328:Adult; D017677:Age Distribution; D000368:Aged; D000483:Alleles; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D016001:Confidence Intervals; D003424:Crohn Disease / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D053590:Interleukin 1 Receptor Antagonist Protein; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D011336:Probability; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D012795:Sialoglycoproteins / Q000235:genetics*
C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D012795:Sialoglycoproteins