Growth Hormone (Gh) treatment usefulness in children with short stature due to Gh bioinactivity

Short stature caused by biologically inactive growth hormone (GH) is rare and characterized by lack of GH action despite its normal immunoreactivity. A dissociation between GH bioactivity and immunoreactivity is present in physiologic conditions, suggesting that standard GH measurements do not provide any information on the biologic activity of the hormone, evaluation that can be performed by the Nb2 cell bioassay. Moreover, the diagnosis of GH bioinactivity should be confirmed by a marked catch-up growth after exogenous GH administration. Aim of our study is to evaluate the activity of GH treatment in subjects with short stature, reduced growth velocity (GV), normal GH response to provocative tests and reduction of GH bioactivity. We studied 10 male, came to our attention for short stature and reduction of GV, aged 10.01±2.60 yr.; weight 24,7±7,5 kg, BMI 15.73±1.92 kg/m2 and bone age 8.17±2.64 yr. All subjects underwent standard GH stimulation tests and Nb2 bioassay that demonstrated the characteristics above described. They were submitted to GH treatment at a dose of 0.24 mg/kg/week.