What is Glucokinase?
Glucokinase (GCK) is a gene which plays an important role in recognising how high blood glucose is in the body. It acts as the “glucose sensor” for the pancreas, so that when blood glucose rises, the amount of insulin produced by the pancreas also increases in response.
What does it mean if there is a change or variation in the GCK gene?
If there is a change (“spelling mistake”) in the GCK gene, fasting blood glucose is “reset” at a higher level than in people without this change. The blood glucose will then be typically raised from birth, and is stable throughout life.
People with these gene changes are diagnosed with “Glucokinase-MODY” (or GCK-MODY, a subtype of “maturity onset diabetes of the young”). Importantly, this rise in blood glucose is mild, very rarely leads to complications, and usually does not need treatment.
How is glucokinase-MODY treated?
Complications of diabetes due to GCK-MODY are rare, therefore no treatment or follow-up is needed. Even if diabetes treatment is started, it may make very little difference to blood glucose levels as the body will keep trying to maintain blood glucose at this mildly raised level.
Why is checking for glucokinase diabetes important in pregnancy?
It is important to know if mum has glucokinase diabetes in pregnancy, because there are differences in how GCK-MODY is managed, compared to gestational diabetes mellitus. If a parent is affected, the baby has a 50% chance of inheriting the GCK gene variant. This may change treatment decisions about whether insulin is used (and the amount needed) to try and control high blood sugars during pregnancy. If mum has been found to have GCK-MODY, it may be advised to do a special blood test (taken from mum) to analyse the baby’s DNA to determine if baby has also inherited this variant. This is possible because when a woman is pregnant, there is a small amount of her baby’s DNA in her bloodstream and by testing mum’s blood sample, we can analyse the baby’s DNA.
GCK-MODY has several important differences from gestational diabetes – it will persist after delivery of the baby, and there is less risk of developing type 2 diabetes in the 10 years following delivery (compared to gestational diabetes mellitus).
How is glucokinase diabetes diagnosed?
A sample of blood will be taken and sent for genetic testing to see if there are variants in the GCK gene which cause GCK-MODY. If you choose to decline testing for this condition, it will not affect the routine care you receive throughout pregnancy from the antenatal diabetes team.
Any personal information is kept confidential. There may be occasions where your information needs to be shared with other care professionals to ensure you receive the best care possible.
In order to assist us to improve the services available, your information may be used for clinical audit, research, teaching and anonymised for National NHS Reviews and Statistics.
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