CNP and obesity due to melanocortin 4 receptor deficiency: Since two previous studies, which suggested a lower plasma CNP concentration in adolescents with overweight/obesity, analyzed plasma CNP concentration at a very narrow age interval, i.e., 11.8±0.4 years for the first study (18) and 12.8±2.4 years for the second study (19), a similar analysis was also performed in this study in a group of 109 children aged 12.64±1.58 years.