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

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 ± 11.2 years and 13 LS patients treated between ages of 5.6 ± 4 to 11.3 ± 3 years 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 (150–200 μg/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.