King’s College London issued a report on March 30, 2014 that showed that a defective gene may be causing people to become obese. The report is titled New study finds strong link between obesity and 'carb breakdown' gene.
This study shows that there is a genetic link between metabolism of carbohydrates and obesity. There is a specific mechanism that inhibits the replication of a key enzyme in saliva that helps to breakdown carbohydrates. This defect is more strongly correlated to obesity than diet content, exercise or other prior factors commonly associated with obesity.
“Previous research has found a genetic link between obesity and food behaviours and appetite, but the new discovery highlights a novel genetic link between metabolism and obesity. It suggests that people's bodies may react differently to the same type and amount of food, leading to weight gain in some and not in others. The effect of the genetic difference found in the latest study appears much stronger link than any of those found before.
Researchers first measured gene expression patterns in 149 Swedish families with differences in the levels of obesity and found unusual patterns around two amylase genes (AMY1 and AMY2), which code for salivary and pancreatic amylase. This was suggestive of a variation in copy numbers relating directly to obesity.”
The study was first done in Sweden. The conclusions from the initial study were retested in a study of twins in the UK, and then further confirmed by studies in China and in France.
“The collaborative team found that the number of copies of the AMY1 gene (salivary amylase) was consistently linked to obesity. Further replication in French and Chinese patients with and without obesity showed the same patterns.
A lower estimated AMY1 copy-number showed a significantly increased risk of obesity in all samples and this translated to an approximate eight-fold difference in the risk of obesity between those subjects with the highest number of copies of the gene and those with the lowest.”
The public perception of obese people is that they have no will power or that they don’t care enough about their health to reduce their weight. This study shows that some people do not have the right metabolic tools to process food normally, and that is making them gain and retain weight.
Additional research in the US has found other genes that are also associated with obesity. These genes are also involved in some cancers and metabolic syndrome, which includes obesity and type II diabetes. The studies in the US are focused on a different gene set using mainly studies on laboratory rats at this point in time. This area of research will offer cancer treatments that will be less destructive to the body's immune system and overall patient health versus existing chemotherapy, radiation or surgical treatments.
There are several possible consequences of this study.
- A simple genetic test using a mouth swap can detect the absence of this key gene replication component.
- If the defective gene is detected, a diet better suited to the patient can be customized to minimize the probability of becoming obese.
- The public perception of obesity may be changed as it is recognized that obesity may be directly related to genetic makeup and not just to patient choices with regard to diet and exercise.
- Gene therapy may have development of modified DNA that specifically targets the genes to produce additional AMY-1 to alter carbohydrate metabolism in patients missing the gene component.
You can learn more about gene therapy through information provided by the American Society of Gene and Cell Therapy. There have been a few successfully treated genetic diseases using gene therapy, with these mainly being in the treatment of defective immune systems in children and adolescents, and in the treatment of hemophilia.
There are many trials for treatment of acquired diseases using gene therapy. The primary focus is for cancer treatment, with stage III trials for breast cancer, prostate cancer and pancreatic cancer. Earlier stage trials are under development to treat other cancers, neurodegenerative diseases, heart disease and diabetes. It is estimated that 2/3 of gene research is currently focused on cancer treatment.
While diet and exercise remain a key factor in most approaches to reducing weight, those patients with genetic defects that impact their metabolic processes can now be diagnosed. In the short-term, modification of the diet and exercise will help reduce weight. In the longer-term, gene therapy may allow these patients to live a more normal lifestyle without risking the diseases related to obesity, e.g. diabetes, heart disease and kidney failure.