Mental and motor development before and during growth hormone treatment in infants and toddlers with Prader–Willi syndrome

BACKGROUND: Prader-Willi syndrome (PWS) is a neurogenetic disorder characterized by muscular hypotonia, psychomotor delay, feeding difficulties and failure to thrive in infancy. GH treatment improves growth velocity and body composition. Research on the effects of GH on psychomotor development in infants with PWS is limited. OBJECTIVE: To evaluate psychomotor development in PWS infants and toddlers during GH treatment compared to randomized controls. DESIGN/PATIENTS: Forty-three PWS infants were evaluated at baseline. Twenty-nine of them were randomized into a GH group (n = 15) receiving 1 mg/m(2)/day GH or a non-GH-treated control group (n = 14). At baseline and after 12 months of follow-up, analysis with Bayley Scales of Infant Development II (BSID-II) was performed. Data were converted to percentage of expected development for age (%ed), and changes during follow-up were calculated. RESULTS: Infants in the GH group had a median age of 2.3 years [interquartile range (IQR) 1.7-3.0] and in the control group of 1.5 years (IQR 1.2-2.7) (P = 0.17). Both mental and motor development improved significantly during the first year of study in the GH group vs. the control group: median (IQR) change was +9.3% (-5.3 to 13.3) vs.-2.9% (-8.1 to 4.9) (P < 0.05) in mental development and +11.2% (-4.9 to 22.5) vs.-18.5% (-27.9 to 1.8) (P < 0.05) in motor development, respectively. CONCLUSION: One year of GH treatment significantly improved mental and motor development in PWS infants compared to randomized controls.