[1] Samsung Med Ctr, Dept Pediat, Seoul, South Korea
[2] Samsung Med Ctr, Dept Radiat Oncol, Seoul, South Korea
[3] Samsung Med Ctr, Dept Family Med, Seoul, South Korea
[4] Samsung Med Ctr, Dept Otorhinolaryngol Head & Neck Surg, Seoul, South Korea
[5] Korea Hemophilia Fdn, Seoul, South Korea