The short child with subnormal plasma somatomedin C

Area of Science:

• Pediatric Endocrinology
• Growth Hormone Research
• Metabolic Studies

Background:

• Establishing normal ranges for plasma somatomedin C is crucial for diagnosing growth disorders in children.
• Previous studies may not have optimized the frequency of blood sampling for accurate somatomedin C assessment.
• Understanding the role of somatomedin C in short stature is essential for effective treatment strategies.

Purpose of the Study:

• To determine the normal range of plasma somatomedin C in healthy children aged 7-10 years.
• To investigate the diagnostic utility of plasma somatomedin C levels in identifying short children.
• To evaluate the efficacy of human growth hormone therapy in short children with varying somatomedin C and growth hormone levels.

Main Methods:

• Plasma somatomedin C levels were measured in 118 healthy children (59 male, 59 female) aged 7-10 years.
• Multiple blood samples were collected at 6-week intervals to establish optimal testing protocols.
• Short children (below the 3rd percentile) were assessed for plasma somatomedin C and growth hormone status; growth hormone therapy was administered for 6 months.

Main Results:

• The 95% tolerance limits for plasma somatomedin C were most accurate when based on the mean of four determinations.
• In short children, 44% had below-normal plasma somatomedin C levels; 19 were growth hormone deficient, 20 were not.
• Both growth hormone-deficient and non-deficient short children showed significant height increases with human growth hormone treatment.

Conclusions:

• A mean of four plasma somatomedin C determinations is recommended for accurate assessment in children.
• Low somatomedin C levels identify a subset of short children who may benefit from growth hormone therapy, irrespective of growth hormone deficiency.
• Human growth hormone therapy is effective in promoting linear growth in short children with hyposomatomedinemia.