Case-control study of IL23R rs76418789 polymorphism, smoking, and ulcerative colitis in Japan

Area of Science:

• Genetics
• Gastroenterology
• Immunology

Background:

• Interleukin-23 (IL-23) plays a role in ulcerative colitis (UC) pathogenesis.
• A prior genome-wide study identified an association between IL23R p.G149R (rs76418789) and UC in Asian populations.
• This study focuses on validating this association within the Japanese population.

Purpose of the Study:

• To investigate the association between the IL23R SNP rs76418789 and ulcerative colitis (UC) in a Japanese cohort.
• To explore potential interactions between rs76418789 and environmental factors, such as smoking, in UC development.

Main Methods:

• A case-control study design was employed.
• The study included 384 UC cases and 661 control subjects.
• Statistical adjustments were made for sex, age, and smoking status.

Main Results:

• The AA genotype of rs76418789 was absent in UC cases but present at 0.5% in controls.
• Carriers of the GA or AA genotypes of rs76418789 exhibited a significantly reduced risk of UC (OR=0.67).
• A significant interaction was found between rs76418789 and smoking history (p=0.03), with smoking increasing UC risk only in individuals with at least one A allele.

Conclusions:

• The IL23R single nucleotide polymorphism rs76418789 is significantly associated with ulcerative colitis in the Japanese population.
• This research highlights a novel interaction between rs76418789 and smoking in the context of UC etiology.