RAC1 was characterised by a higher prevalence of women (77%; RAC2=56%, RAC3=41%) (Chi-squared p=0.013) and obesity, as reflected by elevated body mass index (BMI) (36.8±1.4 kg·m−2) compared with RAC2 (p<0.0001) and RAC3 (p<0.0001) (table 1), and elevated serum high-sensitivity C-reactive protein concentrations (p=0.017 versus RAC2; p=0.002 versus RAC3) and serum interleukin-6 (p<0.003 versus RAC2; p<0.003 versus RAC3) (supplementary table S6). The gene discussed is IL6; the disease is obesity due to melanocortin 4 receptor deficiency.