| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
From University Laboratory of Physiology (K.S., H.d.W., F.A.), Oxford, UK; Department for General Pediatrics (F.H.) and Department for Child Neurology (N.I.W., F.E.), University Pediatric Hospital, Ruprecht-Karls-University of Heidelberg, Germany; and Institute of Biomedical and Clinical Science (S.E.F., S.E., A.T.H.), Peninsula Medical School, Exeter, UK.
* To whom correspondence should be addressed. E-mail: frances.ashcroft{at}physiol.ox.ac.uk.
Abstract Objectives: Activating mutations in the human KCNJ11 gene, encoding the pore-forming subunit (Kir6.2) of the ATP-sensitive potassium (KATP) channel, are one cause of neonatal diabetes mellitus. In a few patients, KCNJ11 mutations cause a triad of developmental delay, epilepsy, and neonatal diabetes (DEND syndrome). The aim of this study was to determine the clinical effects, functional cause, and sensitivity to sulfonylurea treatment of a novel KCNJ11 mutation producing DEND syndrome.
Methods: We screened the DNA of a 3-year-old patient with neonatal diabetes, severe developmental delay, and therapy-resistant epilepsy for mutations in KCNJ11. We carried out electrophysiologic analysis of wild-type and mutant KATP channels heterologously expressed in Xenopus oocytes.
Results: We identified a novel Kir6.2 mutation (I167L) causing DEND syndrome. Functional analysis showed both homomeric and heterozygous mutant channels were less inhibited by MgATP leading to an increase in whole-cell KATP currents. This effect was due to an increase in the intrinsic open probability. Heterozygous channels were strongly inhibited by the sulfonylurea tolbutamide. Treatment of the patient with the sulfonylurea glibenclamide not only enabled insulin therapy to be stopped, but also resulted in improvement in epilepsy and psychomotor abilities.
Conclusions: We report a case of developmental delay, epilepsy, and neonatal diabetes (DEND) syndrome that shows neurologic improvement with sulfonylurea therapy. Early recognition of patients with DEND syndrome may have considerable therapeutic benefit for the patient.
This article has been cited by other articles:
|
|
 |
|
  J. C. Koster, H. T. Kurata, D. Enkvetchakul, and C. G. Nichols DEND Mutation in Kir6.2 (KCNJ11) Reveals a Flexible N-Terminal Region Critical for ATP-Sensing of the KATP Channel Biophys. J., November 15, 2008; 95(10): 4689 - 4697. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Aguilar-Bryan and J. Bryan Neonatal Diabetes Mellitus Endocr. Rev., May 1, 2008; 29(3): 265 - 291. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. C. Koster, F. Cadario, C. Peruzzi, C. Colombo, C. G. Nichols, and F. Barbetti The G53D Mutation in Kir6.2 (KCNJ11) Is Associated with Neonatal Diabetes and Motor Dysfunction in Adulthood that Is Improved with Sulfonylurea Therapy J. Clin. Endocrinol. Metab., March 1, 2008; 93(3): 1054 - 1061. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. C. Cooper and Z. Pan Putting an end to DEND: A severe neonatal-onset epilepsy is treatable if recognized early Neurology, September 25, 2007; 69(13): 1310 - 1311. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
