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Synergistic effect of interleukin-6 promoter (IL6 −634C/G) and intercellular adhesion molecule-1 (ICAM-1 469K/E) gene polymorphisms on the risk of endometriosis in Japanese women


Dr Jo Kitawaki, Department of Obstetrics and Gynecology, Graduate School of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto 602-8566, Japan.


Problem  Endometriosis is an immune-related, chronic inflammatory disease with a polygenic predisposition. The aim of this study was to investigate whether the interleukin-6 (IL-6) gene promoter region polymorphism (−634C/G) and the intercellular adhesion molecule-1 (ICAM-1) gene 469K/E polymorphism are responsible in part for the genetic susceptibility to endometriosis.

Methods of study  The IL-6 −634C/G and ICAM-1 469K/E genotypes were determined in 202 patients with endometriosis and 236 control women by polymerase chain reaction-restriction fragment length polymorphism.

Results  There were no differences in the IL-6 −634C/G or the ICAM-1 469K/E genotypes and allele frequencies between control women and endometriosis patients collectively, or between control women and each clinical subgroup of endometriosis patients. Interestingly, the frequency of ICAM-1 EE homozygotes who concomitantly carried the IL-6 −634G allele was significantly higher in patients with endometriosis (χ2 = 6.458, P = 0.0396, d.f. = 2).

Conclusion  Our results suggest that the IL-6 −634C/G and ICAM-1 469K/E polymorphisms synergistically affect the susceptibility for endometriosis in the Japanese population.