Genetic and/or epigenetic testing is not required for all suspects of GHD but it is suggested in the diagnostic assessment of a patient whose phenotype suggests a high likelihood of a genetic cause (6) such as in case of suspected congenital hypopituitarism, early onset of growth failure, positive family history, height more than 3 SD below the mean, extremely low GH response to GHSTs and, very low IGF-1 and IGFBP-3 levels. The gene discussed is GH1; the disease is non-acquired combined pituitary hormone deficiency.