Growth Hormone Therapy of Turner Syndrome: The Impact of Age of Estrogen Replacement on Final Height

Abstract

Clinical trials of recombinant human GH therapy in Turner syndrome that began more than a decade ago show that GH accelerates the linear growth rate. Several studies indicate that final height is also improved, although the magnitude of the increase has been debated. The age at which feminization is induced could be an important factor in determining the patient’s ultimate growth response. To test this, 60 patients from a large (n = 117), previously unreported, clinical trial of GH treatment were randomly assigned to begin conjugated estrogens at either 12 or 15 yr of age. The 60 patients were all less than 11 yr of age at entry (mean, 9.5 yr) and received 0.375 mg/kg·week of GH for nearly 6 yr on a daily or three times weekly regimen. Height gain was calculated by comparing the study patients’ final or near final heights to their pretreatment projected heights as well as to those of a separate set of age-matched, historical control patients. Patients in whom estrogen treatment was delayed until age 15 yr...