Gastric Bypass Success: Weight Loss Surgery Effectiveness is in Your Genes

During gastric bypass, the stomach will be divided into two parts. The upper part (the pouch) is where the food will go. Image by: NIDDK and NIH

During gastric bypass, the stomach will be divided into two parts. The upper part (the pouch) is where the food will go. Image by: NIDDK and NIH

If you want to lose weight with gastric bypass surgery, your genes may hold the key to success.

Gastric bypass surgery, a weight loss surgery, is one option for those who are significantly obese – when dieting and exercise just aren’t enough.
According to the Mayo Clinic, when you go the surgical route to weight loss, you can expect to lose half or even more of your weight within the first two years.
However, sometimes the results may not be what you had hoped for. This can be due to the band not working correctly, or the patient’s unhealthy diet, but sometimes doctors don’t know why the surgery doesn’t work very well.

In a new study published in The American Journal of Human Genetics, researchers discovered that your genes may predict how much weight you will lose in weight loss surgery.

Weight Loss: It’s In Your Genes

Dr. Lee Kaplan and his colleagues discovered that the amount of weight loss from surgery can be in part, due to the DNA sequencing on chromosome 15. Dr. Kaplan and his team studied genomes of more than 1,000 people who had gastric bypass surgery. They discovered that people who had two copies of a specific varient on chromosome 15 had lost about 39 percent of their body weight, whereas people without this extra varient only lost about 30 percent of their weight. Decoded Science had the opportunity to interview Dr. Kaplan about his research.

Interview with Dr.Kaplan

Decoded Science asked Dr. Kaplan how this extra chromosome plays a role in how much weight loss a person will or will not have. Dr. Kaplan responded, “We do not yet fully understand the mechanism. The GWAS has allowed us to identify this association (between the specific sequence – polymorphism – on chromosome 15 and the amount of weight loss after gastric bypass) but it does not reveal how. The specific sequence identified is not within a gene, but it is near two genes, ST8SIA2 and SLCO3A1.

In our human patients, expression of ST8SIA2 is associated with the amount of post-bypass weight loss, and in our mouse model of gastric bypass (where we can study the specific effects of this operation on gene expression and metabolism throughout the body under more controlled conditions), we have found that gastric bypass specifically alters the expression of these two genes.

These additional observations provide further support for the involvement of these two genes in the weight loss effects of gastric bypass. Understanding the biology of these genes and their protein products should provide clues as to how the variation in DNA sequence on chromosome 15 (rs17702901) influences outcomes after the surgery.

One clue that we do have is that SLCO3A1 encodes a transporter protein that may influence how the reconfigured gut sends signals to the rest of the body (including signals to decrease appetite and burn more energy). Mutation of ST8SIA2 in mice (but not yet humans) has previously been shown to be associated with obesity, so this gene may also be directly involved in body weight and body fat regulation.”

Click to Read Page Two: Outlook for Gastric Surgery Patients

© Copyright 2013 Janelle Vaesa, MPH, All rights Reserved. Written For: Decoded Science

Pages: 1 2