This observation aligns with previous research showing that the expressivity of obesity in individuals with loss-of-function MC4R variants tends to increase over generations, affecting grandparents, parents, and children with growing severity [19]. Unfortunately, in the present study historical BMI data from childhood or adulthood were not available for the affected family members other than the index patient, limiting the ability to compare growth trajectories and further investigate this trend. The gene discussed is MC4R; the disease is Obesity.