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

Background: The diagnosis of GH deficiency (GIlD) is based upon the results of GH stimulation tests, which have several drawbacks. Aim: To evaluate the usefulness of IGP-1 and IGFBP-3 for the diagnosis of GHD in prepuberal children. Material and methods: We measured IGP-1 and IGFBP-3 in three group of subjects: I. GHD (n:24), height <-2SD for age (Z score, average ± SD: -4.2 ± 1.2), growth velocity <p10 (3.4 ± 1,0 cm/year) and peak GH level on two GH stimulation tests <7 ng/ml (1.2 ± 0.6 ng/ml); II. Short non-GHD (NGHD, n:32), height of -2.7 ± 0.9 SD for age, growth velocity <p 25 (3.9 ± 1.2 cm/year), and peak GH level on two GH stimulation tests >7 ng/ml (15.3 ± 6.9 ng/ml), y III. Normal school children (n:35) with normal heights (-0.17 ± 0.12 SD) were studied as controls. Results: IGP-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 ±2 SD of the mean of the control group. Using this criteria, IGP-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.