Two resent studies identified new genetic variants that influence the risk of obesity and insulin resistance. People who are insulin resistant and obese are at risk for developing type 2 diabetes. The study in the UK looked at data from nearly 17,000 people of European descent. The research team led by Dr. Ruth J. F. Loos, from Addenbrooke’s Hospital in Cambridge confirmed prior research linking variants in the FTO gene with obesity. They also found genetic variants near the MC4R gene were strongly associated with obesity.
The MC4R gene influences how much a person eats and how much energy is either expended or conserved thus regulating energy levels. When severe obesity runs in families mutations in this gene are the most common genetic cause. A later study confirmed these results when over 60,000 adults and 5988 children who had the MC4R risk variant were analyzed. A child’s odds of being obese can be 30 percent higher with the MC4R variant. Obese offspring of 660 families studied had an “over transmission” of the risk variant.
The study in London took place at the Imperial College and was led by Dr. Jaspal S. Kooner. This study looked at SNPs. SNPs, (pronounced snips and stands for single nucleotide polymorphisms) are the tiny differences in gene sequence. This investigation looked at the DNA of over 14,000 people of Indian Asian and European descent. They analyzed 318,237 single letter changes, or SNPs, near the MC4R gene.
The results showed that those people with two copies of the risk variant had an additional 2 cm to their waist circumference. They calculated that their insulin resistance was increased by about 10 percent. The goal of the research is to identify people who are genetically most susceptible to diseases such as diabetes and cardiovascular disease. When identified, preventative measures, including life-style choices such as diet and exercise, can help reduce the burden of disease.
I doubt that any of us would turn down an adoption opportunity because there was a family history of obesity. However, knowing that your child is genetically predisposed to obesity should motivate many of your choices for your child. It would be a good idea to stay away from greasy fast food for example and encourage fresh fruits and vegetables. You could also start your child in sports, gymnastics, dance, and clubs at as a toddler to encourage a lifetime of physical fitness.
SOURCE: Reuters Health May 7, 2008
Photo Credit: 2007 Julia Fuller.
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