Gene associated with obesity works through effects on appetite.

Issue date: 06.08.08

Previous studies have demonstrated that the gene, known as FTO, is strongly associated with obesity. However, it was not known whether it affects weight by influencing the amount of food eaten or the amount of calories burnt off. The results of this study strongly suggest that the gene works by modifying appetite, so that the children in the study who had two copies of the higher-risk FTO gene are less likely to have their appetite ‘switched off’ by eating.

The researchers, led by Professor Jane Wardle, UCL Epidemiology & Public Health, tested whether children carrying the higher risk gene had altered appetite in a sample of 3337 unrelated children aged 8-11 years old. This included parental reports of the children’s height, weight and waist circumference and asking parents to complete a specially-designed questionnaire about their children’s eating habits, to assess aspects such as their child’s enjoyment of food and how easily they became full. FTO is the first common obesity gene to be identified in Caucasian populations. Previous studies have shown that adults with two copies of the FTO gene are on average 3kg heavier, and individuals with a single copy are on average 1.5kg heavier, than those without the gene.

The co-author on the paper, Claire Haworth in the MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry at King’s commented: ‘It is exciting to come closer to understanding how the FTO gene might affect obesity. This research suggests that the genetic risk comes from not recognising signs of being full after eating (satiety), which is also exciting because it suggests ways in which this research can be translated into treatment and prevention.’

King’s College London