Skeletal muscle characteristics and motor performance after 2-year growth hormone treatment in adults with prader-willi syndrome

Context: In adults with Prader-Willi syndrome (PWS), abnormal body composition with decreased lean body mass and skeletal muscle (SM) volume has been related to altered GH secretion and may possibly contribute to greatly reduced motor capacity. Objective: The scope of the studywasto test the hypothesis thatGHtreatment has favorable effects on SM characteristics and motor performance in adults with PWS. Design, Setting, and Participants: Fifteen obese PWS subjects (nine males and six females; age range, 19-35 y; body mass index, 37.7-59.9 kg/m2) were investigated before and after 12 (GH12) and 24 (GH24) months of GH treatment. Main Outcome Measures: SM cross-sectional area and SM attenuation were determined with computed tomography at the lumbar and midthigh levels. Maximal isometric handgrip strength and isokinetic knee extension peak torque were measured. Motor performance was evaluated with different indoor walking tests, whereas exercise endurance was assessed with a treadmill incremental test to exhaustion. Results: A condition of severe GH deficiency was found in six patients (40%). GH treatment significantly increased lean body mass (GH12, P <.05; GH24, P <.05), reduced percentage of body fat (GH12, P <.05; GH24, P <.05), and augmented SM cross-sectional area and SM attenuation of both lumbar (GH12, P