A specific mutation in the obesity-related (FTO) gene is associated with body fat mass but not with abdominal fat accumulation in Turkish adults, research suggests.
The study, “Association of FTO common variant (rs9939609) with body fat in Turkish individuals,” was published in the journal Lipids in Health and Disease.
Besides excessive caloric intake, genetic and environmental factors have been reported as contributing to obesity.
The FTO gene codes for an enzyme that repairs damaged DNA and RNA molecules. Although its exact role is not fully known, scientists believe it may be involved in the brain regulation of energy intake, fat formation, and energy consumption in skeletal muscle.
Genetic studies have shown that mutations in the FTO gene are associated with obesity in children and adults. However, studies in the Turkish population have reported conflicting evidence about the frequency and impact on obesity of a specific single nucleotide polymorphism (SNP) in FTO, known as rs9939609. Of note, SNPs are variations in a single nucleotide (the building blocks of DNA).
Investigators at Gazi University Faculty of Health Sciences, in Turkey, set out to investigate the relationship between the rs9939609 mutation and fat accumulation in Turkish individuals.
A total of 200 adults, 18 to 65 years old, underwent genetic screening for FTO gene variants and assessments of body composition.
Results showed that 61.5% of the participants had rs9939609 in one or both copies of their FTO gene. (Every person has two copies of each gene, one inherited from each parent.)
Women had this variant more commonly than men (26% vs. 12%). People with the mutation in both gene copies had significantly more whole-body fat than those with rs9939609 in only one gene copy or individuals without the mutation. Accounting for both body mass index (BMI) and gender did not alter this difference.
In contrast, carrying the FTO variant in one or both gene copies was not associated with differences in abdominal fat amount, internal fat levels, and waist/hip circumference ratio. Also, BMI and the body adiposity index — a ratio of hip circumference to height that estimates body fat in adults — did not differ between gene variant carriers and controls.
“Our study supports that the FTO rs9939609 polymorphism is associated with fat accumulation in the whole body without being associated with abdominal fat accumulation in Turkish adults,” the scientists wrote.
Still, the team added that FTO mutations other than rs9939609 may have a different impact on body fat composition. Not having a significant proportion of obese participants was among the limitations of the study, the researchers noted.