Foot length before and during insulin-like growth factor-I treatment of children with laron syndrome compared to human growth hormone treatment of children with isolated growth hormone deficiency

OBJECTIVE: To compare foot length deficits between patients with Laron syndrome (LS) (primary growth hormone [GH] insensitivity) and congenital isolated GH deficiency (IGHD) and their response to replacement therapy with insulin-like growth factor-I (IGF-I) and hGH, respectively. DESIGN: Data for the study were collected from the records of nine children with LS (3 M, 6 F) 7.8 +/- 4.8 years old (mean +/- SD), and nine children with IGHD (3 M, 6 F), 3.8 +/- 3.3 years old. Fifteen non-treated adult patients with LS were also included in the study. METHODS: Measurements of foot length were recorded without treatment and monitored during 9 years of treatment in the children and in the untreated adult patients. For statistical analysis the non-parametric Mann-Whitney U test was used. RESULTS: With almost similar basal values in growth deficit and pre-treatment growth velocities, the achievements towards norms after 9 years of treatment were greater in the patients with IGHD than in the patients with LS: foot length reached -1.4 +/- 0.8 vs. -3.3 +/- 1.0 SDS (mean +/- SD), and body height -2.2 +/- 1.0 vs. -3.9 +/- 0.5 SDS. The difference between the two groups could be due to the initiation of replacement therapy in the patients with IGHD at a younger age. Adult foot size of untreated patients with LS is small but less retarded than the height deficit. CONCLUSIONS: Both IGF-I and hGH are potent growth stimulating hormones of linear growth and acrae as exemplified by foot growth.