The insulin-like growth factor I generation test in the investigation of short stature |
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Authors: | AM Cotterill,C Camacho-Hü bner,K Woods,C Martinelli,P Duquesnoy,MO Savage |
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Affiliation: | Division of Paediatric Endocrinology, Department of Endocrinology, St Bartholomew's Hospital, London, UK;INSERM U91 Hôpilal Henri Mondor2, 94010 Creteil, France |
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Abstract: | Genotypic and phenotypic heterogeneity in patients with growth hormone (GH) insensitivity syndrome suggests that partial defects exist in the GH receptor. The insulin-like growth factor I (IGF-I) generation test was assessed as a means of identifying partial GH receptor defects in a heterogeneous group of 22 prepubertal children with short stature. In a subgroup of nine patients with peak GH levels of 63.7 ± 3.7 mU/l during a glucagon tolerance test, the response to the IGF-I generation test was no different from that for the group as a whole (peak GH, 43.3 ± 4.5 mU/l), despite the fact that this subgroup exhibited a negative relationship between height SDS and peak GH and a positive relationship between height SDS and IGF binding protein-3. This preliminary study therefore suggests that the IGF-I generation test in its present form will not be useful as a primary screening test for partial GH insensitivity. Despite this, the IGF-I generation test has been extremely useful in the confirmation of the diagnosis of GHIS and may therefore also prove useful in the confirmation of partial defects in the GH receptor. A subgroup of short children with peak GH levels above 40 mU/l had some characteristics of partial GH receptor deficiency. These children, to whom GH therapy would not normally be given, may respond better to recombinant human IGF-I. |
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Keywords: | Growth hormone insensitivity syndrome insulin-like growth factor I generation test short stature partial GH receptor defects |
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