Clinical spectrum of extreme insulin resistance syndromes treated with rhIGF-1: A single-center experience.

CONTEXT: Donohue syndrome (DS) and Rabson-Mendenhall syndrome (RMS) are extreme forms of insulin resistance (IR) caused by biallelic mutations in the insulin receptor gene. Recombinant human insulin-like growth factor-1 (rhIGF-1) treatment is often used but its long-term benefits and risks are still poorly delineated.

OBJECTIVE

We describe rhIGF-1 treatment outcomes of a cohort of patients with DS and RMS, and compare them to previously published patients.

METHODS

A single-center retrospective observational study with case note review was conducted. A literature search was performed for previously published DS and RMS patients treated with rhIGF-1.

RESULTS

rhIGF-1 outcomes beyond 4 months have been reported for only 11 patients with DS and RMS to date. We provide outcome data for 3 more males, and report the long-term clinical course of a patient already described. Metabolic benefits of rhIGF-1 included improved glycemic control and fasting tolerance in early years of life, and some growth enhancement. Two patients exhibited poor response or intolerance to rhIGF-1 and died in infancy. The 2 longest-lived patients had progressive decompensation to diabetes mellitus, in 1 case despite long-term uninterrupted rhIGF-1 therapy. We also describe new features associated with severe insulin receptoropathies, such as cataract, liver hemangioma, and impaired hepatic protein synthesis.

CONCLUSION

The phenotypes of DS and RMS are heterogeneous. Current treatment options remain unsatisfactory as high-dose rhIGF-1 exerts only limited beneficial effects and does not prevent decompensation to diabetes mellitus. More research is needed to identify alternative treatment strategies for extreme forms of IR.