Searchable abstracts of presentations at key conferences in endocrinology
Endocrine Abstracts (2009) 23 OC1.3

BSPED2009 Oral Communications Oral Communications 1 (6 abstracts)

IGF1R gene expression in patients with idiopathic short stature according to GH and IGF1 status

Soraya Sader Milani , Rodrigo Custódio & Carlos Eduardo Martinelli


Department of Paediatrics, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto/São Paulo, Brazil.


The aim of this study was to analyze IGF1R gene expression in patients with idiopathic short stature (ISS) and correlate it with their GH and IGF1 status. In a previous study, we reported lower final height in subjects with ISS and GH peak ≥40 mU/l (Group1, n=16) compared to those with ISS and GH peak between 20 and 40 mU/l (Group2, n=15), after stimulation test (ITT) performed before or during puberty. Patients were 16–24 (Group1) and 15–26 (Group2) years old when recalled for measurements of final height, BMI, serum IGF1 and biochemical determination. At these time whole blood sample were obtained for IGF1R gene expression analysis. While most of Group2 patients had serum IGF1 concentrations around the mean (±1S.D.) Group1 patients had IGF1 mainly above +1S.D. (Group1a) or below −1S.D. (Group1b) (P<0.05). These 3 groups of patients (1a, 1b and 2) showed different BMI and lipid profile suggesting different status of GH–IGF axis activation: partial IGF insensitivity, partial GH insensitivity and normal GH–IGF axis, respectively. The possibility of different expression of IGF1R among these subjects was then considered. The levels of mRNA expression of the IGF1R gene in peripheral leucocytes were analyzed by quantitative real-time PCR and a cut-off for 2−ΔΔCT=2.0 was assumed. IGF1R gene expression was higher in Group1 than in Group2 patients (P=0.03). However, no difference in IGF1R mRNA expression comparing Group1a to Group1b was observed. In conclusion, patients with ISS and high GH peak during stimulation test expressed more IGF1R mRNA than those with GH peak between 20 and 40 mU/l. It could reflect an up-regulation mechanism in attempt to compensate reduced IGF1 action due to either low IGF1 levels or poor signaling. These findings reinforce the existence of different subgroups of patients under the label of ISS that must be better characterized to allow a better clinical approach.

Volume 23

37th Meeting of the British Society for Paediatric Endocrinology and Diabetes

British Society for Paediatric Endocrinology and Diabetes 

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