GENETICS AND EPIGENETICS OF OBESITY

Key words: Obesity, Genetics, Epigenetics, Gene polymorphism

Obesity is, first of all, a matter of genetics and it better develops in conditions of more food availability and sedentary lives as it occurs in rich countries. The control of the energetic balance (intake > accumulation > dispersion) is connected to a complex system of signal molecules that correlate the hypothalamus, the adipocyte, muscular tissue and the adrenal gland. Up to now 7 types of monogenic obesity have been identified in mice or rats but there are few homologous correspondences in men; however it is possible to say that “common” obesity is polygenic, namely due to a number of genes having a quantitative effects (genes QTL - Quantitative Trait Loci). Moreover, the relationship between “common” obesity and single nucleotide polymorhisms (SNP) has been described. Among these genetic variations a special role is attributed to the polymorhisms of a gene recently identified, the FTO (Fat Mass and Obesity Associated). Furthermore, it is well known that remarkable food restrictions during pregnancy (especially in preterm infants) as well as an excessive caloric intake with a rapid ponderal growth after birth cause a rearrangement of the epigenoma that during early adulthood will lead to an obese phenotype mainly associated with metabolic syndrome.