1. Congenital hyperinsulinism caused by hexokinase I expression or glucokinase-activating mutation in a subset of β-cells
- Author
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Henquin, Jean-Claude, Sempoux, Christine, Marchandise, Joelle, Godecharles, Sebastien, Guiot, Yves, Nenquin, Myriam, and Rahier, Jacques
- Subjects
Glucokinase -- Physiological aspects -- Genetic aspects -- Research ,Metabolic diseases -- Risk factors -- Development and progression -- Genetic aspects -- Research ,Glucose metabolism -- Physiological aspects -- Genetic aspects -- Research ,Health - Abstract
Congenital hyperinsulinism causes persistent hypoglycemia in neonates and infants. Most often, uncontrolled insulin secretion (IS) results from a lack of functional [K.sub.ATP] channels in all β-cells or only in β-cells within a resectable focal lesion. In more rare cases, without [K.sub.ATP] channel mutations, hyperfunctional islets are confined within few lobules, whereas hypofunctional islets are present throughout the pancreas. They also can be cured by selective partial pancreatectomy; however, unlike those with a [K.sub.ATP] focal lesion, they show clinical sensitivity to diazoxide. Here, we characterized in vitro IS by fragments of pathological and adjacent normal pancreas from six such cases. Responses of normal pancreas were unremarkable. In pathological region, IS was elevated at 1 mmol/L and was further increased by 15 mmol/L glucose. Diazoxide suppressed IS and tolbutamide antagonized the inhibition. The most conspicuous anomaly was a large stimulation of IS by 1 mmol/L glucose. In five of six cases, immunohistochemistry revealed undue presence of 1ow-[K.sub.m] hexokinase-I in β-cells of hyperfunctional islets only. In one case, an activating mutation of glucokinase (I211F) was found in pathological islets only. Both abnormalities, attributed to somatic genetic events, may account for inappropriate IS at low glucose levels by a subset of β-cells. They represent a novel cause of focal congenital hyperinsulinism., Congenital hyperinsulinism (CHI) is the major cause of severe and persistent hypoglycemia in neonates and infants and is a brain-damaging and potentially life-threatening condition (1-3). Excessive secretion of insulin by [...]
- Published
- 2013
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