🧬 Gene Summary: GCK
(A rare cause of congenital hyperinsulinism involving glucose sensing)
What does the GCK gene do?
The GCK gene provides instructions to make an enzyme called glucokinase. Glucokinase acts as the body’s glucose sensor, especially in the pancreas, helping insulin-producing cells know when blood sugar levels are high enough to release insulin.
How can changes in the GCK gene cause hyperinsulinism?
Certain changes in the GCK gene make glucokinase overactive. This lowers the blood sugar level at which insulin is released, causing the pancreas to release insulin too early or too often.
This can lead to:
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Recurrent low blood sugar (hypoglycaemia)
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Hypoglycaemia beginning in infancy or childhood
This mechanism is different from many other causes of hyperinsulinism and relates to altered glucose sensing.
How common are changes in the GCK gene in hyperinsulinism?
GCK-related hyperinsulinism is relatively rare.
How are changes in the GCK gene inherited?
GCK-related hyperinsulinism is usually inherited in a dominant pattern:
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One altered copy of the gene can cause the condition
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A parent may have mild symptoms or may not realize they are affected
In some cases, the change occurs for the first time in the child (de novo).
💡 A genetic counsellor can help explain inheritance and family implications.
What does a GCK change mean for my child?
Children with GCK-related hyperinsulinism may:
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Have low blood sugar starting early in life
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Need frequent feeds or medication
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Have symptoms ranging from mild to more persistent hypoglycaemia
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Otherwise grow and develop normally
Severity can vary widely, even within the same family.
How does this affect treatment?
Knowing a child has a GCK gene change helps doctors:
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Understand the cause of altered glucose sensing
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Choose appropriate medications (some children respond to diazoxide)
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Plan individualized blood sugar targets and monitoring
Where can I learn more or get support?
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Talk with your child’s hyperinsulinism care team
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Meet with a genetic counsellor
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Connect with hyperinsulinism family support organizations