INS and obesity due to melanocortin 4 receptor deficiency: 1. Growth (weight, length, head circumference)2. Infections (diagnosis of infection rather than specific measurements of infection)3. Bowel function (stool frequency/consistency; constipation, diarrhea)4. Cognitive and psychomotor development5. Obesity/overweight/body composition6. Glucose metabolism/homeostasis (including fasting plasma glucose [FPG], insulin, glycated hemoglobin [HbA1c], C-peptide, others)7. Lipids (low-density-lipoprotein cholesterol [LDL-C]/high-density-lipoprotein cholesterol [HDL-C]/triglycerides [TG]/total cholesterol [TC])8. Gut (fecal) microbiota