Familial hyperproinsulinemia

Diagnosis of p-cell tumors Familial hyperproinsulinemia Cross-reactivity of insulin assays... 

High proinsulin concentrations are usually noted in patients with benign or malignant j3 ceil tumors of the pancreas. Most patients with fl-cell tumors have increased insuhn, C-peptide, and proinsulin concentrations, but occasionally only proinsulin is increased because the tumors have defective conversion of proinsulin to insulin. Despite its low biological activity, proinsuHn production may be adequate to produce hypoglycemia. In addition, a rare form of familial hyperproinsulinemia, produced by impaired conversion to insulin, has been described. Measurement of proinsulin can... 

Insulin-dependent diabetes mellitus type 2, permanent neonatal diabetes mellitus, diabetes mellitus type 1, familial hyperproinsulinemia with or without diabetes... 

The measurement of C-peptide provides a fully validated means of quantifying endogenous insulin secretion, preventing influence of exogenous insulin or insulin antibody. However, most C-peptide assay kits cannot differentiate C-peptide from proinsulin and proinsulin conversion products. The influence of proinsulin may be significant in cases where serum proinsulin is elevated, as in Type 2 diabetes, familial hyperproinsulinemia and in patients with proinsulin antibody. 

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