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GCK gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

GCK gene

The GCK gene provides instructions for making the protein glucokinase, which acts as a sensor to regulate blood glucose levels and insulin release.

Normal Function

The GCK gene provides instructions for making a protein called glucokinase. This protein plays an important role in the breakdown of sugars (particularly glucose) in the body. Glucokinase is primarily found in the liver and in beta cells in the pancreas. Beta cells produce and release (secrete) the hormone insulin, which helps regulate blood glucose levels by controlling how much glucose is passed from the bloodstream into cells to be used as energy. Glucokinase acts as a sensor, recognizing when the level of glucose in the blood rises and helping stimulate the release of insulin from beta cells to control it. In the liver, glucokinase helps determine when excess glucose should be taken in and converted to glycogen, which is a major source of stored energy in the body.

Health Conditions Related to Genetic Changes

Maturity-onset diabetes of the young

Mutations in the GCK gene cause maturity-onset diabetes of the young (MODY), which is a group of conditions characterized by abnormally high blood glucose levels. This form of diabetes usually begins before age 30. GCK gene mutations cause a type known as GCK-MODY (also called MODY2). Affected individuals usually have mildly elevated blood glucose levels from birth, although they typically have no symptoms associated with the condition, and diabetes-related complications are extremely rare.

Most GCK gene mutations involved in GCK-MODY change single protein building blocks in the glucokinase protein or result in an abnormally short version of the protein. The altered protein may be broken down, or the function may be impaired, reducing glucokinase activity in cells. As a result, beta cells are less able to detect changes in blood glucose and release insulin to control it, so blood glucose remains elevated.

Congenital hyperinsulinism

MedlinePlus Genetics provides information about Congenital hyperinsulinism.

Gestational diabetes

MedlinePlus Genetics provides information about Gestational diabetes.

Permanent neonatal diabetes mellitus

MedlinePlus Genetics provides information about Permanent neonatal diabetes mellitus.

Other Names for This Gene

  • ATP:D-glucose 6-phosphotransferase
  • HEXOKINASE 4
  • Hexokinase type IV
  • HK4

Frequently Asked Questions

GCK-MODY often presents with no noticeable symptoms. Individuals typically have mildly elevated blood glucose levels from birth, which are usually discovered incidentally during routine blood tests for other reasons, such as during pregnancy, a general health check-up, or screening for diabetes due to a family history. Unlike other forms of diabetes, GCK-MODY rarely causes classic diabetes symptoms like excessive thirst or urination.
GCK-MODY is diagnosed through genetic testing that identifies mutations in the GCK gene, often after persistent mild hyperglycemia is noted. It differs from Type 1 diabetes because it's not an autoimmune condition and doesn't involve insulin deficiency. It differs from Type 2 diabetes because it's not primarily caused by insulin resistance or lifestyle factors, and it typically presents at a younger age with stable, mild hyperglycemia that doesn't usually progress to severe complications.
The long-term outlook for individuals with GCK-MODY is generally very good. Unlike Type 1 or Type 2 diabetes, GCK-MODY is rarely associated with the typical long-term complications of diabetes, such as kidney disease, nerve damage, or eye problems. The mild, stable elevation in blood glucose usually does not cause significant health issues over a lifetime.
For most individuals with GCK-MODY, specific treatment with medication is not required because the elevated blood glucose levels are usually mild and do not lead to diabetes-related complications. Regular monitoring of blood glucose levels is often sufficient. In some cases, such as during pregnancy, or if glucose levels become significantly higher, specific dietary advice or medications might be considered, but this is less common than in other forms of diabetes.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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