Response to growth hormone-releasing hormone as evidence of hypothalamic defect in optic nerve hypoplasia

Area of Science:

• Pediatric Endocrinology
• Neuro-ophthalmology
• Hormone Research

Background:

• Optic Nerve Hypoplasia (ONH) is a congenital condition affecting vision and potentially endocrine function.
• Hypothalamic-pituitary axis dysfunction is a known complication in some children with ONH.
• Assessing growth hormone (GH) secretion is crucial for managing potential developmental issues in affected children.

Purpose of the Study:

• To investigate hypothalamic-pituitary function in children diagnosed with Optic Nerve Hypoplasia (ONH).
• To evaluate the secretory capacity of growth hormone (GH) in response to specific provocative tests.
• To explore the efficacy of Growth Hormone-Releasing Hormone (GHRH) as a therapeutic intervention.

Main Methods:

• Studied four children with ONH, assessing hypothalamic-pituitary function.
• Utilized glucagon or insulin tolerance tests (ITT) to provoke growth hormone (GH) release.
• Administered bolus injections of Growth Hormone-Releasing Hormone (GHRH).
• High-resolution CT scans were used to assess pituitary tissue presence.

Main Results:

• All four children exhibited growth hormone deficiency when tested with glucagon or ITT.
• A positive response to GHRH bolus injection indicated a primary hypothalamic defect.
• One child with minimal pituitary tissue showed a poor response to provocative tests.
• One child demonstrated an excellent response to subcutaneous GHRH treatment.

Conclusions:

• Children with ONH frequently present with hypothalamic-pituitary dysfunction, specifically GH deficiency.
• The response pattern suggests a primary hypothalamic origin for the observed GH deficiency.
• Subcutaneous GHRH administration represents a physiologically appropriate and effective treatment for GH deficiency in this cohort.