Type a syndrome of insulin resistance: anterior chamber anomalies of the eye and effects of insulin-like growth factor-I on the retina.

Background: The purpose of this work was to describe the anterior chamber and iris anomalies as well as to evaluate the effects of recombinant human insulin-like growth factor-I (rhIGF-I) on the retinal vessels in 2 diabetic patients with type A syndrome of insulin resistance, a rare condition associated with acanthosis nigricans.

Methods: Ophthalmologic examinations, including photographs and fluorescein angiograms, were performed before, and 2 and 4 weeks after starting subcutaneous rhIGF-I treatment, and 3 months after withdrawal of rhIGF-I treatment.

Results: Both patients had goniodysgenesis with mild elevation of the intraocular pressure. Before and after 2 weeks of treatment with rhIGF-I, the fundus and the fluorescein angiograms were mainly normal. After 4 weeks of rhIGF-I treatment both patients' retinas revealed leakage of fluorescein. Three (case 1) and 4 months (case 2) after withdrawal of rhIGF-I, the fundus of all four eyes were again without leakage.

Conclusions: The anterior chamber anomalies found in these patients may be part of the type A syndrome of insulin resistance and could alert clinicians that these patients might not have the usual type of diabetes. Moreover, the data show that exogenous rhIGF-I administration in patients with type A syndrome of insulin resistance alters the permeability of the superficial layer of retinal capillaries which is comparable to the earliest angiographic changes in childhood diabetic retinopathy. Whether this is a direct effect of rhIGF-I, as suggested by experiments in an animal model, or an indirect effect due to the near-normalization of the glucose levels by rhIGF-I warrants further investigations. Finally, this work points to an important caveat regarding the therapeutic use of rhIGF-I in this patient population.