Growth Hormone Binding Protein serum levels are associated to GH Receptor Exon 3 polymorphism in normal children

MARÍA G. BALLERINI; PAULA A. SCAGLIA; HORACIO M. DOMENÉ; MARÍA G. ROPELATO; ALICIA S. MARTÍNEZ; VIVIANA R. PIPMAN; SONIA V. BENGOLEA; LILIANA M. KARABATAS; PATRICIA BEDECARRÁS; JUAN J. HEINRICH; HÉCTOR G. JASPER

Mar del Plata, Buenos Aires, Argentina

Congreso; XIX Reunión Anual de la Sociedad Latinoamericana de Endocrinología Pediátrica (SLEP); 2007

Sociedad Latinoamericana de Endocrinología Pediátrica (SLEP)

GROWTH HORMONE BINDING PROTEIN (GHBP) SERUM LEVELS ARE ASSOCIATED TO GH RECEPTOR EXON 3 POLYMORPHISM IN NORMAL CHILDREN. M. Ballerini1, P. Scaglia2, H. Domené2, M. Ropelato1, A. Martínez2, V. Pipman3, S. Bengolea4, L. Karabatas2, P. Bedecarrás2, J. Heinrich1, H. Jasper2. 1 División Endocrinología Hospital De Niños, Buenos Aires, Argentina. 2 CEDIE-CONICET, Hospital de Niños "R. Gutiérrez", Buenos Aires, Argentina. 3 Servicio De Pediatría Hospital Tornú, Buenos Aires, Argentina. 4 Servicio De Pediatría Hospital Fernández, Buenos Aires, Argentina The GH receptor (GHR) mediates GH action. To our knowledge, there is no information about a possible association between a genomic polymorphism, deletion (D) or retention (F) of GHR exon 3, and GHBP levels in normal subjects. To test this hypothesis we measured GHBP by an in house fluoroimmunoassay (modified from Fisker et al, 1996) and GHR polymorphism determined by multiplex PCR, IGFBP3 by IRMA in 151 normal children (56 boys), aged 5-17yr. Data were expressed as mean±SEM. GHBP serum levels were not significantly related to sex, age or pubertal stages. Nevertheless a tendency to higher GHBP levels in pubertal girls than boys was found (p=0.059). Serum GHBP reference interval was (P2.5–P97.5) 0.96-6.42 nM for girls and 0.86-5.79 nM for boys. GHBP significantly correlated with BMI percentiles (r=0.45, p<0.001). Children carriers of the GHR F/F genotype (n=90) presented significantly higher GHBP levels than carriers of one or two copies of GHR D allele (n=61) (2.9±0.2 vs 2.5±0.2 nM, p=0.02). In a subgroup of 110 children,  68 genotyped F/F presented significantly higher height and IGFBP3 SDS (0.49±0.13 vs 0.05±0.16, p=0.03 and 0.22±0.13 vs -0.23±0.13, p=0.02 respectively).Conclusion: The concomitant finding of greater GHBP and IGFBP-3 levels and a higher height associated to the F/F genotype suggest a regulatory effect of exon 3 GHR polymorphism on GH action.