Primary defect of insulin receptors in skin fibroblasts cultured from an infant with leprechaunism and insulin resistance.

Insulin binding to insulin receptors, on skin fibroblasts established in culture from an infant with insulin resistance and clinical features of leprechaunism was markedly decreased in comparison with cultures from an age-matched control. By contrast, the binding of epidermal growth factor, a polypeptide growth factor chemically unrelated to insulin, to patient's and control fibroblasts was indistinguishable. The selective defect in insulin binding to patient's fibroblasts was reflected in an impaired ability of insulin to stimulate 2-deoxyglucose uptake. These results most likely indicate a primary genetic defect of insulin receptors.