Obesity and Nutritional Health

Genetics and Epigenetics of Obesity

Obesity results from interactions between environmental and genetic components. In spite of a relatively high heritability of common, non-syndromic obesity (40–70%), the search for genetic variations contributing to susceptibility has been a challenging task. Genome wide association (GWA) studies have significantly changed the pace of detection of common genetic susceptibility variations. To date, more than 40 genetic variations have been associated with obesity and fat distribution. In any case, since these variations do not fully explain the heritability of obesity, other forms of variation, such as epigenetics marks, must be considered. Epigenetic marks, or “imprinting”, influence gene expression without actually changing the DNA sequence. Disappointments in imprinting are known to cause extreme shapes of obesity, but have moreover been convincingly related with susceptibility to obesity. Moreover, environmental exposures during critical developmental periods can influence the profile of epigenetic marks and result in obesity.