LAUSR

OBJECTIVE The diagnosis of growth hormone deficiency (GHD) in children is not always straightforward because IGF-1 or GH stimulation tests may not be able to discriminate GHD from constitutional delay of growth and puberty (CDGP) or other causes of short stature. DESIGN Boys and girls, n=429, (0.7 - 16 years old) that attended our department for short stature, participated in this study. They were followed up for an average period of 9 years (4-15). At the end of follow up, a definitive diagnosis was assigned to each individual, and all the components of ternary complex (IGF-1, IGFBP-3, ALS and IGF-1/IGFBP-3 ratio) were evaluated as biomarkers for the respective diagnosis. RESULTS All components of ternary complex were tightly correlated with each other and positively related to age. IGF-1, IGFBP-3, ALS, and IGF-1/IGFBP-3 ratio differed significantly between GHD and normal groups. IGF-1 and ALS levels were lower in GHD compared to children with familial short stature, while IGF-1 and IGF-1/IGFBP-3 ratio was significantly lower in GHD compared to children with CDGP. IGF-1 and IGF-1/IGFBP-3 Receiver Operating Curves (ROC) cutoff points were unable to discriminate between GHD and normal or between GHD and CDGP groups. CONCLUSION Despite the tight correlation among all components of the ternary complex, each one shows a statistically significant diagnosis-dependent alteration. There is a superiority of IGF-1, ALS and IGF-1/IGFBP-3 ratio in the distinction between GHD and CDGP or GHD and normal groups but without usable discriminating power, making thus auxology the primary criterion of establishing the diagnosis.