Of the remaining 34/74 (46 %) patients who were retested, IGF-1 levels alone were available and low enough to confirm GHD (≤ -2 SD for age and gender) in 19/34 (56 %) of which 15 had MPHD and 4 had IGHD (organic causes and abnormal pituitary MRI). This evidence concerns the gene IGF1 and isolated congenital growth hormone deficiency.