Extreme obesity is not a very common medical condition in Taiwanese general population. Although the causes of common obesity are generally considered as multi-factorial, genetic causes may be much more prevalent in the population with morbid obesity. Monogenic or Mendelian obesity include two major categories: 1. single gene mutations, usually involving the appetite regulatory genes in the biological pathways within hypothalamus; 2. genetic syndromes which are characterized by the other physical features in addition to obesity. These monogenic obesity syndromes are in general severe and early onset. Therefore, these may comprise the genetic causes of certain proportions of morbid obesity. On the other hand, morbid obesity may also be polygenic. The obesity in this category may be relatively late onset. However, the contributions from the genetic and epigenetic variations of the monogenic obesity genes can not be overlooked, especially in the subgroup with intermediate age of onset. Genetic study using subjects with morbid obesity will help identify new biological pathways in appetite control and energy homeostasis.
|
