Genomic variants at 20p11 were associated with body fat mass in the European population

OBJECTIVE Body fat mass (BFM) is more homogeneous and accurate than body total mass in measuring obesity but has rarely been studied. Aiming to uncover the genetic basis of fat-induced obesity, a genome-wide association meta-analysis of BFM, after adjustment by body lean mass, was performed in the European population. METHODS Three samples of European ancestry were included in the meta-analysis: the Framingham Heart Study (N = 6,004), the Kansas City osteoporosis study (N = 2,207), and the Omaha osteoporosis study (N = 968). RESULTS At the genome-wide significance level (α = 5.0×10-8 ), a cluster of 10 single-nucleotide polymorphisms (SNPs) at chromosomal region 20p11 that were associated with BFM (lead SNP rs2069126, P = 1.82×10-9 , closest gene SLC24A3) was identified in 9,179 subjects. One of the top SNPs, rs6046308 (P = 3.74×10-8 ), was found to be nominally significant for body fat percentage in another independent study (P = 0.03, N = 75,888) and was reported to transregulate the expression of the MPZ gene at 1q23.3 (unadjusted P = 9.78×10-6 , N = 1,490). Differential gene expression analysis demonstrated that SLC24A3 and CFAP61 at the identified locus were differentially expressed in tissues of people with versus without obesity (P = 3.40×10-5 and 8.72×10-4 , N = 126 and 70), implying their potential role in fat development. CONCLUSIONS These results may provide new insights into the biological mechanism that underlies fat-induced obesity pathology.