Owing to insufficient data on the efficacy of GH in children with GFR above 60 ml/min/1.73 m2 and the weak effect of mildly decreased GFR on longitudinal growth, we do not recommend use of GH in short children with CKD stage 1 or 2 (ref.49) unless they have other conditions, such as nephropathic cystinosis, that predispose to poor growth50. This evidence concerns the gene GH1 and cystinosis.