Utilidad de la determinación del factor de crecimiento insulino-simil tipo I (IGF-I) y de su proteína ligante tipo 3 (IGFBP-3) en el diagnóstico de la deficiencia de hormona de crecimiento en niños / Usefulness of the measurement of insulin-like growth factor 1 (IGF-I) and IGF-1 binding protein-3 (IGFBP-3) for the diagnosis of growth hormone (GH) deficiency in children

Background: The diagnosis of GH deficiency (GHD) is based upon the results of GH stimulation tests, which have several drawbacks. Aim: To evaluate the usefulness of IGF-1 and IGFBP-3 for the diagnosis of GHD in prepuberal children. Material and methods: We measured IGF-I and IGFBP-3 in three group of subjects: I. GHD (n:24), height <-2SD for age (Z score, average ñ SD: -4.2 ñ 1.2), growth velocity 7 ng/ml (15.3 ñ 6.9 ng/ml), y III. Normal school children (n:35) with normal heights (-0.17 ñ 0.12 SD) were studied as controls. Results: IGF-1 and IGFBP-3 were significantly lower in GHD than in NGHD and controls (p <0.001), and in NGHD than in C (p <0.001). We defined the normal range of both proteins as ñ 2 SD of the mean of the control group. Using this criteria, IGF-I was low in 21/24 GHD, and in 12/32 NGHD. IGFBP-3 was low in 22/24 GHD, and in 6/32 NGHD. Only 1 GHD patient had both exams in the normal range, suggesting that he is probably NGHD. 4/32 of the NGHD had both exams below normal range, suggesting that they are probably GHD. Conclusions: IGF-1 and IGFBP-3 are important tools for the diagnosis of GHD