Understanding of the range of GH responsiveness in GH deficiency, and particularly in non-GH deficiency disorders such as Turner syndrome, short stature related to birth size small for gestational age (SGA) and idiopathic short stature (5), has led to development of prediction models of growth response (6) and a recognition that GH therapy needs to be tailored to each child, depending on their diagnosis and individual characteristics. This evidence concerns the gene GH1 and Turner syndrome.