MC4R and obesity due to melanocortin 4 receptor deficiency: As evident in Table 2, although the cohort is too small to establish statistical significance, the data clearly point to early-onset obesity in individuals homozygous for the MC4R mutation: of the children (ages 1–7 years) within the kindred, the two homozygotes were morbidly obese (BMI 37 and 37; Z scores 3.12, 3.08) as compared to the two wild type individuals (BMI 18 and 17) and the heterozygous individual (BMI 17) that were within normal BMI values (85th BMI-per age percentile).