Polymorphisms of the Interleukin - 6 Gene and Bone Mineral Density at Postmenopause in Korean Women / 대한내분비학회지

ABSTRACT

BACKGROUND: Interleukin-6 (IL-6) is one of the candidate cytokines to play an important role in bone loss followed by estrogen deficiency. Recently, the IL-6 VNTR (various number tandem repeats) genotype was reported to be associated with bone mineral density, raising the possibility that genotyping at this site might be of value in identifying women who are at risk for postmenopausal osteoporosis. To evaluate whether allelic variants in the gene encoding the polymorphism of VNTR located at the 3 flank of the IL-6 gene in Koreans were also the same as those of Caucasian, we analyzed the distribution pattern of the polymerase chain reaction product of the IL-6 gene. METHODS: The IL-6 VNTR were examined in 134 postmenopausal Korean women. Bone mineral densities were measured by DEXA (dual energy X-ray absorptiometry, Lunar Radiation, Madison, WI). RESULTS: The IL-6 VNTR polymorphism of Koreans was different from that of Caucasian, and four genotypes (KaKb, KbKb, KbKc and KbKd) were identified. The genotypes KaKb and KbKd were found only in one individual each and most Koreans had KbKb or KbKc genotypes. The overall prevalences of KbKb and KbKc genotypes were 76.9% Rlld 21.6%, respectively, and the distribution patterns of the genotypes were not different among normal, osteopenic and osteoporotic groups. The values of bone mineral density at the lumbar spine and femoral neck were not different between the frequent genotypes of KbKb and KbKc. Furthermore, the levels of alkaline phosphatase, osteocalcin and urinary deoxypyridinoline/creatinine were also not different between the two genotypes. CONCLUSION: There are ethnic differences in IL-6 VNTR polymorphism, and IL-6 VNTR polymorphism may not be associated with postmenopausal osteoporosis in Korean women. Our data suggest that the analysis of IL-6 VNTR polymorphism may not be helpful in detecting patients at risk of developing osteoporosis.