Endocrine Abstracts

JOINT948

Background: Insulin-like growth factor 1 (IGF-1) serves as a key biomarker in assessing growth and puberty-related conditions. Variations in IGF-1 levels reflect underlying pathophysiological changes, helping to differentiate between normal growth and growth-related disorders such as Growth Hormone Deficiency (GHD), Turner Syndrome, and Constitutional Delay of Puberty (CDP). However, standardizing IGF-1 cut-offs across different conditions remains challenging.

Objective of the Review: This review consolidates data from multiple studies to summarize the diagnostic IGF-1 cut-offs across various growth and puberty-related conditions and highlights its utility and limitations as a diagnostic tool.

Material and Methods: A comprehensive analysis was performed by synthesizing findings from studies published in peer-reviewed journals. Data on IGF-1 levels in conditions such as CDP, Small for Gestational Age (SGA), Chronic Malnutrition, GHD, Turner Syndrome, and rare genetic mutations were extracted and compared.

Results: 1. IGF-1 cut-off for normal growth: Typically ranged between 150-200 ng/ml across conditions.

2. GHD: Consistently indicated by IGF-1 levels < 100 ng/ml in multiple studies.

3. SGA: IGF-1 levels < 100 ng/ml or 110 ng/ml in various studies supported its role as a disease marker.

4. Turner Syndrome: IGF-1 < 120 ng/ml was associated with disease states, with larger studies reinforcing this threshold.

5. Chronic Malnutrition and Thalassemia Major: IGF-1 levels < 90 ng/ml and < 70 ng/ml, respectively, indicated growth disturbances.

6. Rare conditions: IGF1R mutations presented variable or fluctuating IGF-1 levels, reflecting unique pathophysiology.

Discussion: IGF-1 levels provide a reliable diagnostic indicator for many growth-related disorders, with thresholds helping clinicians differentiate between normal and pathological growth states. Larger studies, particularly on conditions like Turner Syndrome, provide robust diagnostic thresholds, while rare cases emphasize the variability due to genetic and environmental factors.

Conclusions: IGF-1 is a critical diagnostic marker for growth and puberty-related conditions. While general thresholds like IGF-1 < 100 ng/ml for GHD and SGA are well-supported, variability in levels across different conditions and populations necessitates cautious interpretation alongside clinical context.