The availability of an unlimited amount of recombinant GH (rhGH) allowed for investigating its efficacy in a number of conditions other than GHD, including Turner syndrome (TS), SHOX deficiency, Noonan syndrome (NS), Prader–Willi syndrome (PWS), children born small for gestational age (SGA), idiopathic short stature (ISS) and chronic kidney disease. The gene discussed is GH1; the disease is Prader-Willi syndrome.