Serum bone GLA-protein in growth hormone deficient children

Abstract

Serum bone GLA-protein (BGP), a sensitive and specific marker of bone formation, was measured in 54 normal children and in 50 children with growth disorders. In normal children, the pattern of variations of serum BGP with age was similar to the pattern of variations of the growth velocity. Mean serum BGP was very high during the first year of life (25.3 ± 8.5 ng/ml), decreased to 14.8 ± 2.2 ng/ml from 2 to 6 years, increased to 18.4 ± 4.1 ng/ml from 7 to 10 years and to 18.8 ± 6.5 ng/ml from 11 to 14 years. After puberty, mean sBGP decreased to 12.9 ± 5.4 ng/ml from 15 to 18 years and to 6.5 ± 1.4 ng/ml in young adults. In 32 patients with untreated growth hormone (GH) deficiency, mean sBGP was markedly lower than in age matched controls (6.8 ± 4.4 ng/ml vs. 17.5 ± 4.9 ng/ml, p < .001). In 19 patients with GH deficiency who were undergoing treatment with human GH, sBGP was higher than in untreated patients (20.5 ± 9.3 ng/ml vs. 6.8 ± 4.4 ng/ml, p < .001) and was not different from controls. Repeated measurements performed in 14 GH-deficient patients under chronic GH therapy showed that serum BGP: (1) increased in most patients during treatment (p < .005); (2) was correlated with the duration of treatment (p < .001); (3) decreased to pretreatment values after discontinuing therapy. In conclusion, our data suggest that serum BGP is a sensitive marker of skeletal growth in normal children and in children with growth deficiency, and that measurement of serum BGP might be useful to assess the effects on bone metabolism of hormones and/or drugs that stimulate bone growth and maturation.