Due to the ongoing epidemic of obesity in Brazil [20], the objective of this study was to assess in a cross-sectional and in a prospective way the association of different obesity measurements (BMI, WC and % FM) and IL-6, CRP and adiponectin at 22 years, in a population Birth Cohort in Southern Brazil. The gene discussed is IL6; the disease is obesity due to melanocortin 4 receptor deficiency.