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KCNJ11 gene

potassium voltage-gated channel subfamily J member 11
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Normal Function

The KCNJ11 gene provides instructions for making parts (subunits) of the ATP-sensitive potassium (K-ATP) channel. Each K-ATP channel consists of eight subunits. Four subunits are produced from the KCNJ11 gene, and four are produced from another gene called ABCC8.

K-ATP channels are found in beta cells, which are cells in the pancreas that secrete the hormone insulin. The K-ATP channels are embedded in cell membranes, where they open and close in response to the amount of glucose in the bloodstream. Glucose is a simple sugar and the primary energy source for most cells in the body. Closure of the K-ATP channels in response to increased glucose triggers the release of insulin out of beta cells and into the bloodstream, which helps control blood sugar levels.

Health Conditions Related to Genetic Changes

Congenital hyperinsulinism

More than 30 mutations in the KCNJ11 gene have been found to cause congenital hyperinsulinism. This condition causes frequent episodes of low blood sugar (hypoglycemia), decreased energy, and irritability. Most of these mutations change single protein building blocks (amino acids) in the protein sequence, reducing or preventing activity of the K-ATP channels. Loss of K-ATP channel function leads to the constant release of insulin from beta cells. As a result, glucose is rapidly removed from the bloodstream. Without treatment, the hypoglycemia caused by congenital hyperinsulinism may result in serious complications such as intellectual disability and seizures.

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Permanent neonatal diabetes mellitus

At least 30 mutations in the KCNJ11 gene have been identified in people with permanent neonatal diabetes mellitus. Individuals with this condition often have a low birth weight and develop increased blood sugar (hyperglycemia) within the first 6 months of life.

KCNJ11 gene mutations that cause permanent neonatal diabetes mellitus change single amino acids in the protein sequence. These mutations result in K-ATP channels that do not close, leading to reduced insulin secretion from beta cells and impaired blood sugar control.

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Gestational diabetes

MedlinePlus Genetics provides information about Gestational diabetes

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Maturity-onset diabetes of the young

MedlinePlus Genetics provides information about Maturity-onset diabetes of the young

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Other disorders

Other KCNJ11 gene mutations that have a relatively mild effect on K-ATP channel function as compared to that seen in permanent neonatal diabetes mellitus (see above) cause a condition called transient neonatal diabetes mellitus. Infants with this condition have hyperglycemia during the first 6 months of life, but their blood sugar returns to normal by age 18 months. However, affected individuals usually develop hyperglycemia again during adolescence or early adulthood. As in permanent neonatal diabetes mellitus, KCNJ11 gene mutations that cause transient neonatal diabetes mellitus also interfere with K-ATP channel closure and lead to a reduction in insulin secretion.

A normal variation (polymorphism) in the KCNJ11 gene is associated with an increased risk of type 2 diabetes, the most common form of diabetes. This variant leads to a change in the K-ATP channel, replacing the amino acid glutamic acid with the amino acid lysine at position 23, written as Glu23Lys or E23K. People with type 2 diabetes have hyperglycemia because the body does not respond correctly to the insulin secreted from beta cells. The same variant has also been associated with changes in the heart's response to stress, leading to an increased risk of heart failure. Although changes in the KCNJ11 gene can be associated with type 2 diabetes and heart failure, a combination of lifestyle, genetic, and environmental factors all play a part in determining the risk of these complex disorders.

Other Names for This Gene

  • ATP-sensitive inward rectifier potassium channel 11
  • beta-cell inward rectifier subunit
  • BIR
  • HHF2
  • IKATP
  • inward rectifier K(+) channel Kir6.2
  • inwardly rectifying potassium channel KIR6.2
  • KIR6.2
  • MGC133230
  • potassium channel, inwardly rectifying subfamily J member 11
  • potassium channel, inwardly rectifying subfamily J, member 11
  • potassium inwardly-rectifying channel, subfamily J, member 11
  • TNDM3

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Research Resources

References

  • Bennett K, James C, Hussain K. Pancreatic β-cell KATP channels: Hypoglycaemia and hyperglycaemia. Rev Endocr Metab Disord. 2010 Sep;11(3):157-63. doi: 10.1007/s11154-010-9144-2. Review. Citation on PubMed
  • Flanagan SE, Clauin S, Bellanné-Chantelot C, de Lonlay P, Harries LW, Gloyn AL, Ellard S. Update of mutations in the genes encoding the pancreatic beta-cell K(ATP) channel subunits Kir6.2 (KCNJ11) and sulfonylurea receptor 1 (ABCC8) in diabetes mellitus and hyperinsulinism. Hum Mutat. 2009 Feb;30(2):170-80. doi: 10.1002/humu.20838. Review. Citation on PubMed
  • Flanagan SE, Edghill EL, Gloyn AL, Ellard S, Hattersley AT. Mutations in KCNJ11, which encodes Kir6.2, are a common cause of diabetes diagnosed in the first 6 months of life, with the phenotype determined by genotype. Diabetologia. 2006 Jun;49(6):1190-7. Epub 2006 Apr 12. Citation on PubMed
  • Gloyn AL, Siddiqui J, Ellard S. Mutations in the genes encoding the pancreatic beta-cell KATP channel subunits Kir6.2 (KCNJ11) and SUR1 (ABCC8) in diabetes mellitus and hyperinsulinism. Hum Mutat. 2006 Mar;27(3):220-31. Review. Citation on PubMed
  • Gloyn AL, Weedon MN, Owen KR, Turner MJ, Knight BA, Hitman G, Walker M, Levy JC, Sampson M, Halford S, McCarthy MI, Hattersley AT, Frayling TM. Large-scale association studies of variants in genes encoding the pancreatic beta-cell KATP channel subunits Kir6.2 (KCNJ11) and SUR1 (ABCC8) confirm that the KCNJ11 E23K variant is associated with type 2 diabetes. Diabetes. 2003 Feb;52(2):568-72. Citation on PubMed
  • James C, Kapoor RR, Ismail D, Hussain K. The genetic basis of congenital hyperinsulinism. J Med Genet. 2009 May;46(5):289-99. doi: 10.1136/jmg.2008.064337. Epub 2009 Mar 1. Review. Citation on PubMed
  • Polak M, Cavé H. Neonatal diabetes mellitus: a disease linked to multiple mechanisms. Orphanet J Rare Dis. 2007 Mar 9;2:12. Review. Citation on PubMed or Free article on PubMed Central
  • Reyes S, Park S, Johnson BD, Terzic A, Olson TM. KATP channel Kir6.2 E23K variant overrepresented in human heart failure is associated with impaired exercise stress response. Hum Genet. 2009 Dec;126(6):779-89. doi: 10.1007/s00439-009-0731-9. Citation on PubMed or Free article on PubMed Central
  • Rubio-Cabezas O, Klupa T, Malecki MT; CEED3 Consortium. Permanent neonatal diabetes mellitus--the importance of diabetes differential diagnosis in neonates and infants. Eur J Clin Invest. 2011 Mar;41(3):323-33. doi: 10.1111/j.1365-2362.2010.02409.x. Epub 2010 Nov 4. Review. Citation on PubMed
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