The interleukin-6 promoter polymorphism in Gaucher disease:: a new modifier gene?

Background: Individuals with Gaucher disease vary significantly with regard to degree of bone disease, but there are no predictive markers for severity of skeletal involvement. Aim: To determine the frequency of polymorphisms of interleukin-6 (IL-6) among patients with Gaucher disease, and the relationship to bone mineral density (BMD) and other markers of disease severity. Design: Case-control study. Methods: Genotyping for the 174G --> C promoter polymorphism of IL-6 was performed in adult patients with Gaucher disease for whom there was concurrent bone mineral density (BMD) data and in healthy Ashkenazi Jewish controls. Results: The prevalence of allelic variants (58% G/G, 36% G/C, and 6% C/C) was similar in Ashkenazi Jewish adults with Gaucher disease as in Ashkenazi Jewish controls, but significantly different (p < 0.05) from that reported among Caucasians. No statistically significant correlation was found between IL-6 genotypes and BMD or markers of severity of Gaucher disease. Patients with the C/C genotype had relatively mild Gaucher disease. Discussion: The IL-6 polymorphisms appear to be distributed differently in Ashkenazi Jews than among other Caucasians. In Gaucher disease, the C/C genotype may be associated with a milder Gaucher phenotype, and may serve as a mitigating genetic modifier.