Reversible Growth Hormone Excess in Two Girls with Neurofibromatosis Type 1 and Optic Pathway Glioma

Abstract

Background: A total of 12 children with neurofibromatosis type 1 (NF-1) with optic pathway glioma (OPG) and growth hormone (GH) excess are reported to date, but no data exist on the long-term outcome. We describe 2 girls with NF-1 with OPG and GH excess treated with somatostatin analogue (SSa) who maintained a normal GH axis after stopping SSa therapy. Methods: The diagnosis of GH excess was established from auxological data, persistently high levels of insulin-like growth factor 1 (IGF-1) and a lack of GH suppression during an oral glucose tolerance test. Results: Both patients were started on SSa treatment. During treatment, growth deceleration and normal IGF-1 levels were documented. The first case stopped treatment following the development of SSa side effects. The second case interrupted SSa when, closed to her final height, a normal IGF-1 level was documented. While off treatment, both cases maintained normal IGF-1 levels and appropriate growth velocity for their age and development, with normal GH secretion on biochemical testing. Both cases received treatment for central precocious puberty. Conclusion: GH excess in NF-1 children with OPG can be reversed and only short-term SSa therapy may be required. The aetiology remains undetermined, but the course suggests a hypothalamic dysfunction.