Common genetic variation in sFRP5 is associated with fat distribution in men.

Considering the role of sFRP5 in Wnt signalling, an important group of pathways regulating adipogenesis and inflammation, we performed a genetic association study on sFRP5 polymorphisms in a population of obese and lean individuals. Using information from the HapMap, two tagSNPs were identified in the sFRP5 gene region and genotyped on a population of 1,014 obese, non-diabetic individuals and 606 lean controls. We performed logistic and linear regression analysis including a wide variety of obesity parameters (BMI, waist circumference, height, WHR, fat mass, fat mass percentage and visceral, subcutaneous and total abdominal fat), in addition to OGTT and HOMA-IR values. We were able to show a significant association of sFRP5 with both total abdominal and subcutaneous fat. The association signal was only seen in obese males, and in this population, the minor allele of rs7072751 explains 1.8 % of variance in total abdominal fat. In addition, we saw a trend towards an association of rs10748709 with glucose metabolism. Although further research is necessary, we can conclude that sFRP5 is a significant regulator of fat development and distribution in obese males. We postulate that altered transcription factor binding on the rs7072751 surrounding sequence might play a role in the associations we found with both total abdominal and subcutaneous fat. In addition, although no conclusive evidence was found, our results indicate that sFRP5 genetic variation may affect glucose metabolism and it would be interesting to investigate this further.