Growth hormone insensitivity and severe primary deficiency of insulin-like growth factor-1. Treatment in childhood

Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) play a fundamental role in somatic growth. Defects in the GH-stimulated signalling cascade underlie rare forms of GH resistance, which typically lead to severe growth impairment with reduced serum IGF-1. For a large proportion of patients the genetic background remains unclear; therefore the term severe primary IGF-1 deficiency (SPIGFD) was introduced. Since 2007, recombinant IGF-1 (rIGF-1) has been approved for the treatment of SPIGFD. Treatment with rIGF-1 led to an increase in final body height of approximately 13 cm in several studies but is not comparable to the increase in final height that is typically seen in GH-deficient children after GH substitution. Important side effects of rIGF-1 are hypoglycemia and the proliferation of lymphatic tissue. Adult height frequently remains below the normal range. Due to the complexities in the management of these rare diseases, treatment with rIGF-1 should be restricted to experienced pediatric endocrinologists.