Primary insulin-like growth factor-1 (IGF-1) deficiency (IGFD) is defined by low levels of IGF-1 without growth hormone (GH) deficiency and absence of secondary causes. The aim of this study was to evaluate IGF-1 in Egyptian children with idiopathic short stature (ISS) and describe patients with IGFD. Methods: This cross-sectional study included 50 children with ISS following up at the Diabetes Endocrine and Metabolism Pediatric Unit at Cairo University Pediatric Hospital. Children were included based on the following criteria: (1) short stature with current height standard deviation score (SDS) ≤-2.5; (2) age between 2 and 9 years in boys and 2 and 8 years in girls, and (3) prepubertal status. Exclusion criteria were: (1) identified cause of short stature and (2) pubertal children. IGF-1-deficient children were defined as children without GH deficiency and with IGF-1 levels below the 2.5th percentile. Results: Among 50 children with ISS, 14 (28%) patients had low IGF-1 levels, consistent with the diagnosis of primary IGFD. When compared with non-IGFD children, IGFD children had lower birth weight SDS (-1.8 vs. -0.7 SDS, p < 0.0001) and lower height SDS (-4.2 vs. -3.1 SDS, p < 0.05) and more delayed bone age (2.6 vs. 1.6 years, p = 0.001). Conclusion: Primary IGF-1 deficiency is found in 28% of children with ISS.
