Genes for obesity

Body fat distribution is an inherited trait, and obesity and fat accumulation predispose individuals to many diseases. Accumulation of fat around the stomach, for example, increases the risk of cardiovascular and metabolic diseases.

Two recent studies have identified over 100 new genetic signatures associated with obesity and fat distribution in humans, providing new insights into factors that contribute to these traits.

The findings are based on genetic data from over half a million individuals, as part of the GIANT research project.

The aim of the GIANT project is to identify genes that regulate human body size and shape.

In one study, researchers examined the genetic determinants of fat distribution and the influence of these factors on cardiovascular and metabolic diseases in 224,459 individuals. They identified 49 sites in the genome associated with waist-to-hip ratio - a measure of body fat distribution - including 33 novel loci and 19 additional novel loci for other measures of waist and hip circumference.

The genetic regulation of body fat distribution was found to vary between the sexes as some of the loci displayed stronger effects in women than men. Analyses indicate that the loci seem to contribute to variation in fat distribution by affecting processes involved in fat cell development, blood vessel formation, gene expression and metabolic regulation.

In the second study, researchers investigated the genetic basis of the body mass index (BMI), a common measure of overall obesity. Their finding, involving up to 339,224 individuals, identified 97 genetic loci associated with BMI, of which 56 were novel.

These results indicate that the central nervous system plays a role in obesity susceptibility. They also highlight genes and biological processes that affect BMI, including a pathway that responds to changes in feeding and fasting. This observation supports the idea that identifying genes and pathways associated with obesity could reveal new targets for weight-loss therapies.

The papers, one and two, have been published in Nature.