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Insulin-like growth factors I and II in evaluation of growth retardation
Insights
Measuring insulin-like growth factors (IGF)-I and -II in children helps distinguish growth hormone deficiency. Combining IGF-I and IGF-II assays improves diagnostic accuracy for growth disorders.
Area of Science:
- Pediatric endocrinology
- Growth hormone disorders
- Biochemical diagnostics
Background:
- Growth hormone (GH) deficiency impacts childhood growth.
- Insulin-like growth factors (IGF)-I and -II are key mediators of GH action.
- Accurate diagnosis of GH deficiency is crucial for timely intervention.
Purpose of the Study:
- To evaluate the diagnostic utility of plasma IGF-I and IGF-II levels in differentiating GH-deficient children from normal short children.
- To determine if combined IGF-I and IGF-II measurements enhance diagnostic discrimination.
Main Methods:
- Radioimmunoassays were used to measure plasma IGF-I and IGF-II levels.
- Samples were analyzed from three groups: GH-deficient children, normal short children, and children with normal height.
- Statistical analysis was performed to compare IGF levels across groups.
Main Results:
- A significant overlap in individual IGF-I and IGF-II levels was observed between GH-deficient and normal short children.
- Eighteen percent of GH-deficient children had normal IGF-I, and 32% of normal short children had low IGF-I.
- Fifty-two percent of GH-deficient children and 35% of normal short children exhibited low IGF-II levels.
- Combined assessment revealed that only 4% of GH-deficient children had normal levels of both IGF-I and IGF-II, compared to 0.5% of normal children and 11% of normal short children.
Conclusions:
- Individual plasma IGF-I or IGF-II levels show considerable overlap in GH-deficient and normal short children.
- Simultaneous measurement of both IGF-I and IGF-II may offer improved diagnostic discrimination for growth disorders.
- This combined approach could aid in distinguishing between true GH deficiency and constitutional short stature.
Abstract:
Plasma samples from 68 growth hormone (GH)-deficient children (provocative serum GH level less than 7 ng/ml), 44 normal short children, and 197 children with normal height were assayed by specific radioimmunoassays for the somatomedin peptides, insulin-like growth factors (IGF)-I and -II. Eighteen percent of the GH-deficient children had IGF-I levels within the normal range for age, whereas 32% of normal short children had low IGF-I levels. Low IGF-II levels were found in 52% of GH-deficient children, but also in 35% of normal short children. However, only 4% of GH-deficient children had normal plasma levels of both IGF-I and IGF-II. Furthermore, only 0.5% of normal children and 11% of normal short children had low plasma levels of both IGF-I and IGF-II. We conclude that plasma levels of either IGF-I or IGF-II overlap in GH-deficient and normal short children, but that the combination of radioimmunoassays may permit better discrimination among normal, normal short, and GH-deficient children.