Diazoxide-unresponsive congenital hyperinsulinism in children with dominant mutations of the β-cell sulfonylurea receptor SUR1

Courtney M. MacMullen, Qing Zhou, Kara E. Snider, Paul H. Tewson, Susan A. Becker, Ali Rahim Aziz, Arupa Ganguly, Show Ling Shyng, Charles A. Stanley

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

OBJECTIVE - Congenital hyperinsulinemic hypoglycemia is a group of genetic disorders of insulin secretion most commonly associated with inactivating mutations of the β-cell ATP-sensitive K+ channel (K ATP channel) genes ABCC8 (SUR1) and KCNJ11 (Kir6.2). Recessive mutations of these genes cause hyperinsulinism that is unresponsive to treatment with diazoxide, a channel agonist. Dominant KATP mutations have been associated with diazoxide-responsive disease. We hypothesized that some medically uncontrollable cases with only one KATP mutation might have dominant, diazoxide-unresponsive disease. RESEARCH DESIGN AND METHODS - Mutations of the KATP genes were identified by sequencing genomic DNA. Effects of mutations on KATP channel function in vitro were studied by expression in COSm6 cells. RESULTS - In 15 families with diazoxide-unresponsive diffuse hyperinsulism, we found 17 patients with a monoallelic missense mutation of SUR1. Nine probands had de novo mutations, two had an affected sibling or parent, and four had an asymptomatic carrier parent. Of the 13 different mutations, 12 were novel. Expression of mutations revealed normal trafficking of channels but severely impaired responses to diazoxide or MgADP. Responses were significantly lower compared with nine SUR1 mutations associated with dominant, diazoxide-responsive hyperinsulinism. CONCLUSIONS - These results demonstrate that some dominant mutations of SUR1 can cause diazoxide-unresponsive hyperinsulinism. In vitro expression studies may be helpful in distinguishing such mutations from dominant mutations of SUR1 associated with diazoxide-responsive disease.

Original languageEnglish (US)
Pages (from-to)1797-1804
Number of pages8
JournalDiabetes
Volume60
Issue number6
DOIs
StatePublished - Jun 1 2011

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

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    MacMullen, C. M., Zhou, Q., Snider, K. E., Tewson, P. H., Becker, S. A., Aziz, A. R., Ganguly, A., Shyng, S. L., & Stanley, C. A. (2011). Diazoxide-unresponsive congenital hyperinsulinism in children with dominant mutations of the β-cell sulfonylurea receptor SUR1. Diabetes, 60(6), 1797-1804. https://doi.org/10.2337/db10-1631