Endocrine Abstracts

JOINT505

Background: The IGF-1 generation test evaluates the ability to produce IGF-1 in response to growth hormone (GH) stimulation, providing diagnostic insights into growth disorders. The variability of IGF-1 responses across different conditions highlights its utility in differentiating underlying pathophysiological mechanisms.

Objective of the Review: To summarize findings from studies investigating IGF-1 generation test responses across diverse growth disorders and assess its diagnostic and therapeutic implications.

Material and Methods: Data were synthesized from 16 studies involving over 1,200 pediatric patients with conditions such as GHD, Idiopathic Short Stature (ISS), Small for Gestational Age (SGA), Turner Syndrome (TS), Noonan Syndrome (NS), Thalassemia Major (TM), and chronic malnutrition. Studies reviewed included IGF-1 baseline levels, post-stimulation responses, and their correlation with GH therapy outcomes.

Results: Table:

1. GHD: Patients exhibited significantly reduced IGF-1 generation, confirming GH deficiency (Ghigo et al., 2000; Stanley et al., 2015).

2. SGA: Consistently reduced IGF-1 production due to intrauterine growth restriction was noted, persisting despite GH therapy (Boguszewski et al., 1995; Finken et al., 2006).

3. Turner Syndrome: Reduced IGF-1 responses indicated partial GH insensitivity, though GH therapy improved height outcomes (Rosenfeld et al., 1998).

4. Chronic Malnutrition: Impaired IGF-1 production was attributed to protein-energy malnutrition, even with normal GH levels (Bozzola et al., 1997).

5. ISS: Normal IGF-1 generation ruled out GH insensitivity as a contributing factor (Colle et al., 1999; Misra et al., 2012).

6. Thalassemia Major: Iron overload and nutrient deficiencies impaired IGF-1 generation, affecting growth outcomes (Soliman et al., 2009).

7. Noonan Syndrome: Mild GH insensitivity led to a blunted IGF-1 response, with GH therapy still showing growth improvement (Binder et al., 2005).

Discussion: The IGF-1 generation test provides critical insights into GH sensitivity and function across growth disorders. Reduced IGF-1 generation often correlates with GH insensitivity or systemic factors such as malnutrition or iron overload. Normal IGF-1 generation, as in ISS, helps exclude GH resistance as a primary cause.

Conclusions: IGF-1 generation tests are invaluable for diagnosing and managing pediatric growth disorders. While reduced IGF-1 responses often confirm GH dysfunction or systemic impediments, condition-specific variability necessitates individualized clinical interpretations.