NOS3 and obesity due to melanocortin 4 receptor deficiency: Several studies have assessed the relationship between DNA methylation in obesity markers, including RXRα and NOS3, in umbilical cord blood cells with childhood adiposity [67], pre-proopiomelanocortin (POMC) in peripheral blood cells with an increased individual risk for the development of obesity [37], melanin-concentrating hormone receptor 1 (MCHR1) in peripheral blood cells [68] and the androgen receptor (AR) promoter in peripheral blood leukocytes with body mass index (BMI) or fat mass [69].