KCNQ1 Long QT Syndrome Patients Have Hyperinsulinemia and Symptomatic Hypoglycemia

• DOI: 10.2337/db13-1454
• Publication Date: 2013-12-20T01:14:16Z
• Authors: Signe S. Torekov; Eva Iepsen; Michael Christiansen; Allan Linneberg; Oluf Pedersen; Jens J. Holst; Jørgen K. Kanters; Torben Hansen
• Keywords: Hyperinsulinemia; Hyperinsulinemic hypoglycemia

Patients with loss-of-function mutations in KCNQ1 have long QT syndrome (LQTS). encodes a voltage-gated K(+) channel located both cardiomyocytes and pancreatic β-cells. Inhibition of β-cells increases insulin secretion. Therefore LQTS patients may exhibit increased Fourteen patients, from six families, diagnosed were individually matched to two randomly chosen BMI-, age-, sex-matched control participants underwent an oral glucose tolerance test (OGTT), hypoglycemia questionnaire, continuous monitoring. mutation carriers showed release (area under the curve 45.6 ± 6.3 vs. 26.0 2.8 min ⋅ nmol/L insulin) β-cell sensitivity had lower levels plasma serum potassium upon stimulation hypoglycemic symptoms. Prolonged OGTT four available subjects revealed after 210 (range 1.4-3.6 4.1-5.3 mmol/L glucose), 24-h profiles that spent 77 18 per 24 h states (<3.9 glucose) 36 10 (<2.8 0 for participants. The phenotype LQTS, caused by KCNQ1, includes, besides QT, hyperinsulinemia, clinically relevant symptomatic reactive hypoglycemia, low challenge, suggesting explain some cases "essential" hypoglycemia.