title: The insulin-like growth factor I generation test in the investigation of short stature.
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.
authors.affiliation: Division of Paediatric Endocrinology, St Bartholomew's Hospital, London, UK.
authors.forename: A M
authors.initials: AM
authors.lastname: Cotterill
authors.forename: C
authors.initials: C
authors.lastname: Camacho-Hübner
authors.forename: K
authors.initials: K
authors.lastname: Woods
authors.forename: C
authors.initials: C
authors.lastname: Martinelli
authors.forename: P
authors.initials: P
authors.lastname: Duquesnoy
authors.forename: M O
authors.initials: MO
authors.lastname: Savage
mesh_terms: D001827:Body Height; D002648:Child; D005260:Female; D006130:Growth Disorders / Q000175:diagnosis*; D013006:Growth Hormone / Q000097:blood / Q000502:physiology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis*; D008297:Male; D011986:Receptors, Somatotropin / Q000172:deficiency
chemical_list: D011986:Receptors, Somatotropin; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone