In the present study, although we found a strong correlation between TG and serum apelin concentration in obese girls after adjusting for BMI and age, the relationship was insignificant in non-obese subjects, suggesting that the association may be more pronounced above a certain threshold determined by the extent of obesity, or that TG may affect apelin levels by inducing insulin resistance. The gene discussed is APLN; the disease is obesity due to melanocortin 4 receptor deficiency.