Obesity Research & Clinical Practice (2009) 3, 3—8 ORIGINAL ARTICLE The obesity of patients with Laron Syndrome is not associated with excessive nutritional intake Shira Ginsberg a , Zvi Laron a,* , Mira Arbiv Bed b , Nachum Vaisman b a Endocrinology and Diabetes Research Unit, Schneider Children’s Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Petah Tikva 49202, Tel Aviv, Israel b Unit of Clinical Nutrition, Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Received 5 August 2008; received in revised form 10 November 2008; accepted 12 November 2008 KEYWORDS Laron Syndrome; Primary GH insensitivity; Obesity; Caloric intake; REE Summary Objective: To study the metabolic parameters which may affect the excessive weight of treated and untreated patients with Laron Syndrome. Design: Body composition, daily caloric intake and resting energy expenditure (REE), when possible, were measured for each patient. Caloric intake was calculated based on 7-day food records, REE was measured by indirect calorimetry and body compo- sition was determined by dual energy X-ray absorptiometry (DEXA). Subjects: Nine untreated adult subjects with Laron Syndrome (6 female subjects, 3 male subjects) aged 28—53 years and 4 girls with Laron Syndrome treated by insulin-like growth factor-I (IGF-I) 120—150 g/kg/d were included in the study. Results: Patients with Laron Syndrome have an abnormally high body fat (BF) mass (54 ± 10% of body weight) and a relatively low lean body mass (LBM) compared to a healthy normal population. Energy intake varied but in most of the patients was not significantly higher than the measured REE. The REE corrected for LBM was higher than expected, based on our norms for healthy adults. The mean distribution of energy sources in the food was 47% carbohydrates, 17% protein and 36% fat. Conclusion: The severe obesity of patients with Laron Syndrome is not due to hyper- phagia or hypometabolism. © 2008 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved. ∗ Corresponding author. Tel.: +972 3 9253610/1; fax: +972 3 9222996. E-mail address: laronz@clalit.org.il (Z. Laron). Introduction Laron Syndrome Type I (LS = OMIM 262500), also called primary growth hormone insensitivity or resistance, is a rare autosomal recessive disease caused by deletions or mutations in the growth 1871-403X/$ — see front matter © 2008 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.orcp.2008.11.001