Concerning her low weight and height for her age (both below the 3rd percentile), in 2004, researchers carried out a study of nine children diagnosed with Jacobsen’s syndrome, eight of whom had low height, only four had reduced levels of insulin-like growth factor-1 (IGF1), and the others had normal levels,13 as did the patient reported in this study, who also did not have a deficit in growth hormone (GH). This evidence concerns the gene GH1 and Jacobsen syndrome.