Final height in young women with Turner syndrome after GH therapy: an opencontrolled study

GH therapy has been applied to patients with Turner syndrome for over a dec ade, but small sample size, delayed initiation of therapy into adolescent a ge and comparison with historical control subjects limit the usefulness of these studies for appraisal of the effect of GH on final adult height. We r eport 49 young women with Turner syndrome who completed a clinical trial in an open, non-randomized, age-matched controlled study of GH, given as dail y s.c. injections at a weekly dose of 8.2 mg/m(2) for 1.9-7.5 years. Final height was defined as the measurement taken 2 years or more after height ve locity declined below 2 cm/year and after a bone age of 15 'years'. The gai n in height was evaluated in three ways, The mean final height gain, compar ed with the control group, was 4.4 cm. When corrected for the projected hei ght at inception of therapy the mean gained height was 5.3 cm above the con trol group, Shorter girls showed better response to GH then did taller girl s. After correcting for parental height, the mean gain was 4.7 cm. The adul t height of the GH-treated Turner women was significantly correlated with t he target height, whereas no such correlation was obtained for control untr eated women. Furthermore, no correlation was observed between height gain a nd the age or duration of GH therapy or the age of inception of estrogen re placement therapy. It is concluded that GH therapy augments final height of girls with Turner syndrome by a mean 4.4-5.3 cm, depending on the method o f evaluation, and that shorter girls may be preferred candidates for such t herapy. GH therapy can be initiated after age 10 years and there is no reas on to delay estrogen therapy beyond the age of 12. Indirect evidence sugges ts that high-dose GH therapy may surmount a pathophysiological resistance i n the GH-IGF-I axis.