Introduction Prader-Willi syndrome is a complex, multisystem disorder characterized by hypotonia, hyperphagia, obesity, short stature, delayed or absent puberty, and mental retardation. Short stature is a central feature of PWS and appears to be caused by dysregulation of the GH/IGF axis in which both GH and IGF levels may be low. We reviewed a large Prader-Willi clinical population at Baylor College of Medicine to investigate the long-term effects of GH therapy on linear growth.
Methods Retrospective data were collected from a clinical Prader-Willi population of 112 patients at Baylor College of Medicine. Sixty-two patients did not receive GH therapy; 50 patients did receive GH therapy. These patients were followed between 1 and 18 years and GH treatment was initiated at varying ages. Linear growth was measured at each visit. The raw data were inputted into Excel and analyzed using linear regression and proc mixed in SAS V8 and GLM repeated measures in SPSS 12.0.
Results GH therapy increases height z-score primarily in years 1 to 2 of therapy (p < .05). Thereafter, it maintains the increased height z-score, causing a relative progressive increase in height z-score compared to the untreated group (p < .05) The age of the patient at which GH treatment was initiated also had an effect on height z-score; starting at an earlier age resulted in more positive height z-scores compared to the untreated group (p < .01).