Is fatness in the genes?

Scientists at Boston Children's Hospital have discovered that mice carrying a faulty version of a gene called Mrap2 gain weight, even while eating the same amount as their genetically normal counterparts. The gene is involved in a signalling pathway in the brain that increases energy burning while decreasing appetite.

Writing in the journal Science, the scientists suggest that mice with a faulty version of Mrap2 seemed to be hanging on to fat rather than burning it. Interestingly, the animals gained even more weight on a high fat diet, compared to regular mice. Faults in the human version of the gene have also been found in severely obese people, although they're only found only in less than 1 per cent of the obese population, suggesting that MRAP2 could play an important role in weight control and energy balance.