A gene has been discovered to cause an increase in an individual's body fat percentage, with its suppression in mice leading to lower body fat percentages.

Researchers in Japan have shown that a gene, HSP47, is involved in the body's fat storage processes and could explain an individual's genetic susceptibility to gaining body fat under normal or high calorie intake situations.

'The findings from our study highlight the significant role that HSP47 plays in determining an individual's amount of body fat normally and in response to various factors such as disease or changing hormone levels,' said lead author, Dr Jihoon Shin, associate professor at the Department of Metabolic Medicine, Osaka University.

The study, which was published in Nature Communications, aimed to identify genes potentially linked to conditions associated with obesity and increased adiposity (body fat). The scientists screened publicly available genetic databases and noted that levels of the HSP47 protein were increased in obesity, feeding and overeating and decreased in exercise training and calorie restriction.

Furthermore, insulin, a hormone associated with blood sugar control was found to increase HSP47 levels, while cortisol, a hormone associated with a chronic stress response decreased HSP47 levels.

By analysing genetic and transcriptomic data, the study team found single nucleotide polymorphisms in the HSP47 gene that were associated with increased protein expression in fatty tissue, but not in others such as liver, heart or pancreas. The study reported that these variants were commonly found across different ethnic groups, including African, American, European, East Asian and South Asian ethnicities, suggesting a potential common global effect on adiposity.

The team further demonstrated that inactivation of the gene in knockout mice studies led to a reduction in adiposity, without change to weight or food intake. Using a pharmacological compound to inhibit the HSP47 protein in mice similarly reduced adiposity levels.

Adiposity varies greatly between individuals and increases with obesity. High adiposity is associated with significant health concerns, such as cardiovascular disease, diabetes and certain cancers such as breast and colon cancer. Findings from this study could explain individual variation in body fat deposition and help further understanding as to how it can be influenced.

'We hope that this study will contribute to the broader scientific community and advance our understanding of the complex interplay between genetic, environmental, and lifestyle factors in regulating body adiposity,' wrote the study authors.