Although, there are a few studies reporting the relationship between leptin and 25(OH)D in adolescents with obesity, previous studies in adults revealed that measures of adiposity largely explained the negative association of serum 25(OH)D with leptin, and that MM, %BF, and serum 25(OH)D had an impact on serum leptin (5, 32). The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.