[1] Seoul Natl Univ Hosp, Dept Pediat, Div Pediat Endocrinol & Metab, Seoul 110744, South Korea
[2] Seoul Natl Univ, Boramae Hosp, Dept Pediat, Seoul 110744, South Korea
[3] Seoul Natl Univ, Coll Med, Canc Res Inst, Dept Pediat, Seoul 110744, South Korea