Head circumference in untreated and IGF-I treated patients with Laron syndrome: Comparison with untreated and hGH-treated children with isolated growth hormone deficiency

Abstract

BackgroundHead circumference (HC) is a simple and practical measure of brain size, development and longitudinal measurements of the HC in childhood are an index of brain growth. ObjectiveTo determine the effects of long IGF-I deficiency and treatment on HC in patients with Laron syndrome (LS). Patients20 untreated adult LS patients, aged 48.4±11.2years and 13 LS patients treated between ages of 5.6±4 to 11.3±3years were studied. 15 patients with congenital IGHD treated between age 6.1±4 and 13±4 by hGH served as controls. MethodsHC was expressed as standard deviation (SD) and Ht as SDS. HC was measured and plotted on Nellhaus charts. Linear height (Ht) was measured by a Harpenden Stadiometer. ResultsThe mean HC deficit of the adult untreated LS males was −2.9±0.6 SD compared to a Ht deficit of −7.0±1.7 SDS. The HC of the LS adult females was −3.6±1 SD compared to a Ht SDS of −6.9±1.5 (p<0.001). IGF-I treatment (150–200μg/kg once daily) increased the HC from −3.3±0.9 (m±SD) to normal values (0.87±1.8 SD) (p<0.001) in 11/13 children. The Ht SDS deficit decreased only by 1.5 SDS. hGH treatment of cIGHD children increased the HC from −2.0±1.8 to 0.3±1.2 SD and the Ht SDS from −4.8±1.6 to 1.6±1.0. Conclusionsa)Untreated children and adults with LS and cIGHD have a reduced HC (i.e. brain size). IGF-I treatment of LS children and hGH treatment of IGHD children induced a fast catch-up growth denoting the role of IGF-I on brain growth.b)Comparison between IGF-I and hGH on linear growth stimulation revealed a greater potency of hGH.