PLASMA ICFI AND IGF-BP3 LFVELS AS DIAGNOSIS CRITERIA OF GH DEFICIENCY

Abstract

Idiopathic GH deficiency (GHD) is a clinically and biologically heterogeneous condition, making it difficult to diagnose. We have shown that the magnetic resonance imaging (MRI) aspect (Argyropoulon, J pediatr 1992, p.886) and the growth response during the first 2 yrs of hGH therapy are good criteria of GHD. Forty nine patients with height of ←2SD and a GH peak response after 2 pharmacological stimulation tests of < 10 ng/ml were classified according to the accuracy of the diagnosis of GHD: Group I (n=22) certain GHD with pituitary stall interruption or familial form;m Group II (n=14) without these criteria; Group III (n=13) tranisient GHD with GH peak ≥ 10 ng/ml after a 3rd provocative test performed after a 15-d interruption of hGH therapy. In groups II and III pituitary height on MRI was normal in 9,←2SD in 6 and not evaluated in 12 patients. Other causes of short stature were excluded. IGFI was measured in the plasma without extraction by the non-equilibrium technic described by Furlanetto and al. and IGF-BP3 by a RIA (DSL., Webster, Texas). The results were compared to those found in prepubertal idiopathic short childre : lowest limits were 0.2u/ml and 2 μg/ml for IGFI and IGF-BP3 respectively (m±SE : 0.8±0.1 u/ml and 4±10 1 μ/ml). GH peak, IGFI and IGF-BP3 were lower(p<0.001) in I than in II and III. In Group I, these 3 parameters were not modified by associated thyrotropin deficiency (10 cases) or spontateous hypoglycemia (9 cases). Conclusion. Almost all patients with certain GHD had low values of IGFI and IGF-BP3. Conversely those with transient form and /or normal pituitary anatomy had normal values. Pituitary stalk interruption, height increase ≥ ISD during the 1st years of hGH therapy, IGFI<0.2u/ml, and IGF-BP3<2μg/ml are markers of the diagnosis of GHD. When these criteria are absebt or disordant further evaluation is necessary. (supported by a grant from Assistance Publique-Hopitaux de paris.)