AIMS: Pediatric onset of Crohn disease (CD) is characterized by male sex predominance while adult-onset disease demonstrates female sex predominance. It has been postulated that this phenomenon may be genetically determined or due to an effect of estrogen on age of onset. Interleukin (IL)-6 modulates the TH17 pathway, and the IL-6 promoter is modulated by estrogen, possibly linking genetically determined inflammation and the presence of estrogen. The aim of our study was to investigate whether differences in IL-6 promoter genotype could explain male sex in earlier disease onset. PATIENTS AND METHODS: We genotyped 333 patients with CD and 100 controls, 162 pediatric-onset patients (age of onset 18 years and younger) for the IL-6-174 polymorphic site. Genotype, sex, and age of onset were compared. RESULTS: Males with IL-6-174GG genotype (the wild-type allele) had an increased risk for a younger age of onset compared to males with IL-6-174GC or CC genotype (G --> C genotype), hazard ratio (HR) 1.49, P = 0.02, 95% confidence interval (CI) 1.07-2.09. Females with GG genotype were not found to have an increased risk for a younger age of onset compared with females with G --> C genotype, HR 1.01, P = 0.96, 95% CI 0.72-1.41. CONCLUSIONS: Males with IL-6-174GG genotype are prone to develop CD at a younger age than males with the IL-6-174G --> C genotype. Our study suggests that age of onset may be modified by the IL-6-174GG genotype and this modification is sex dependent. This may be due to increased transcription of IL-6, an effect that may be repressed by estrogen in females.
AIMS: Pediatric onset of Crohn disease (CD) is characterized by male sex predominance while adult-onset disease demonstrates female sex predominance. It has been postulated that this phenomenon may be genetically determined or due to an effect of estrogen on age of onset. Interleukin (IL)-6 modulates the TH17 pathway, and the IL-6 promoter is modulated by estrogen, possibly linking genetically determined inflammation and the presence of estrogen. The aim of our study was to investigate whether differences in IL-6 promoter genotype could explain male sex in earlier disease onset. PATIENTS AND METHODS: We genotyped 333 patients with CD and 100 controls, 162 pediatric-onset patients (age of onset 18 years and younger) for the IL-6-174 polymorphic site. Genotype, sex, and age of onset were compared. RESULTS: Males with IL-6-174GG genotype (the wild-type allele) had an increased risk for a younger age of onset compared to males with IL-6-174GC or CC genotype (G --> C genotype), hazard ratio (HR) 1.49, P = 0.02, 95% confidence interval (CI) 1.07-2.09. Females with GG genotype were not found to have an increased risk for a younger age of onset compared with females with G --> C genotype, HR 1.01, P = 0.96, 95% CI 0.72-1.41. CONCLUSIONS: Males with IL-6-174GG genotype are prone to develop CD at a younger age than males with the IL-6-174G --> C genotype. Our study suggests that age of onset may be modified by the IL-6-174GG genotype and this modification is sex dependent. This may be due to increased transcription of IL-6, an effect that may be repressed by estrogen in females.
Authors: Nick Powell; Jonathan W Lo; Paolo Biancheri; Anna Vossenkämper; Eirini Pantazi; Alan W Walker; Emilie Stolarczyk; Francesca Ammoscato; Rimma Goldberg; Paul Scott; James B Canavan; Esperanza Perucha; Natividad Garrido-Mesa; Peter M Irving; Jeremy D Sanderson; Bu Hayee; Jane K Howard; Julian Parkhill; Thomas T MacDonald; Graham M Lord Journal: Gastroenterology Date: 2015-04-25 Impact factor: 22.682