engleski

Genome-wide meta-analysis of brachial circumference

Brachial circumference (BC), also known as upper arm or mid arm circumference, can be used as an indicator of muscle mass and fat tissue, which are differently distributed in men and women. Analysis of anthropometric measures of peripheral fat distribution such as BC could help in understanding complex phenotypes such as obesity. The purpose of this study is to identify genetic variants associated with BC through a large-scale genome-wide association scan (GWAS) meta-analysis. To identify sex-specific effects underlying BC we used fixed-effects meta-analysis to synthesise summary results from 14 GWAS on 8, 961 males, 9, 792 females and on the combined set of 18, 753 individuals. Individual studies carried out two sets of analyses using linear regression and an additive genetic model: adjusted for age and adjusted for age and BMI. Out of the 6 stratified meta-analysis, we observed an excess of signal for the female-specific age-and-BMI adjusted stratum (4 SNPs with p-values<1x10-6 observed, versus 2.4 SNPs expected under the null). We also found more signals for the age-and-BMI adjusted meta-analysis across males and females (37 SNPs with p-values<1x10-5) compared to the null hypothesis of no association (24 SNPs expected under the null). 24 SNPs have been taken forward for de novo genotyping in independent sample sets. In this first GWAS meta-analysis for BC to date, we have identified promising signals within the power constraints of this study, which we are following up by attempting replication in independent datasets.

brachial circumference; mid arm circumference; genome wide association scan meta-analysis; single nucleotide polymorphism; quantitative trait

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