Question

Obesity is a multifactorial disease with strong environmental/lifestyle component. On the other hand, it is believed that obesity also is having significant genetic component. Describe different lines of evidences pointing toward the importance of the genetic component in the obesity (10 points).

Answer 1

Obesity is a disease which is caused by accumulating and stores excessive amounts of body fat. Increased in calorie intake and decreased in physical activity is one factor that causes obesity in today's world. However, genetic component also plays an important role in obesity. Examples of genetic obesity are specific disorders like Bardet-Biedl syndrome and Prader-Willi syndrome. A spontaneous mutations in genes, which are responsible for appetite control and food intake can cause monogenetic obesity. This single gene defect cause obesity in childhood and the person can suffered from high levels of hunger, and becoming obese because of consistent overeating. This is called hyperphagia. But genetic changes in human populations doesn't have much impact on obesity epidemic, the main impact is in populations whose environments promote physical inactivity and increased consumption of high-calorie foods. However, neither all people living in such environments will become obese, nor all obese people have the same body fat distribution or suffer the same health problems. So, this variation in how people respond to the same environment proved that genes also play a important role in the development of obesity.  An example is implicated gene, MC4R. It encodes the melanocortin 4 receptor.