Adult Heights of 258 Girls with Turner Syndrome on Low Dose of Growth Hormone Therapy in Japan

Growth hormone (GH) therapy was approved in 1999 for only GH-deficient Turner syndrome (TS) in Japan. It was subsequently approved for all cases of TS regardless of GH secretory status since 1999. The dose of GH is 1.0 u (0.35 mg)/kg/wk at present, but it was 0.5 u (0.175 mg)/kg/wk before 1999. The adult height in patients with TS on the dose of 0.5 u/kg/wk was studied from the report on of Foundation for Growth Science in 2000. GH therapy was registered for 920 cases, and 258 cases reached adult height. The mean adult height was 145.7 cm. The adult height in patients with TS without GH therapy was reported to be 138 cm in Japan. Thus, the height gain by GH treatment was 7.7 cm. The mean age at the start of GH therapy was 12.0 yr old. The mean duration of GH therapy was 5.6 yr. The mean age at the start of estrogen therapy was 17.0 yr old. Patients in Japan were older at the start of GH and estrogen therapy than in the US and Europe at that time. The adult height and gain of height SD were not correlated with age at the start GH therapy in this study. This may be the result of the older age at the start of GH therapy and the low dose of the GH therapy. Patients are beginning to start GH therapy at a much earlier age and the dose has been doubled in Japan. We expect that the recent data concerning adult height in the patients with TS after GH therapy will improve better than this report.