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Glucokinase hyperglycaemia testing within maternity services

This project aims make identification of glucokinase hyperglycaemia in pregnancy a routine part of antenatal care across the East Midlands and East of England.

What is glucokinase hyperglycaemia?

Glucokinase hyperglycaemia is a subtype of monogenic diabetes, otherwise known as Maturity Onset Diabetes of the Young (MODY).

Monogenic (mono = one; genic = gene) diabetes is a rare, genetic form of diabetes, which is different from both type 1 and type 2 diabetes as it caused by a change in a single gene.

Over 40 different genes have been identified which, when a change occurs, can cause monogenic diabetes. It accounts for less than 5% of all diabetes cases in the UK and it is thought around 80% of patients are initially misdiagnosed with another form of diabetes. Many subtypes of monogenic diabetes can also be called otherwise known as Maturity Onset Diabetes of the Young (MODY).

Glucokinase hyperglycaemia is a change in the glucokinase gene which causes a mildly raised fasting (before breakfast) blood glucose (sugar).

Genes provide instructions to help our bodies develop, grow and work. Genes are inherited from our parents. Changes in the GCK gene can therefore be inherited, which means the change can be passed on from parent to child.

Although glucokinase hyperglycaemia causes mildly raised blood sugar, it is not known to cause long term health problems and outside of pregnancy does not require any treatment or monitoring. People with glucokinase hyperglycaemia are at no higher risk of developing type 2 diabetes than the rest of the population.

Typically, people with glucokinase hyperglycaemia tend to be slim, and often have a parent diagnosed with diabetes. 1 in 1000 people have glucokinase hyperglycaemia.

Glucokinase hyperglycaemia is not diabetes.

People with Glucokinase hyperglycaemia tend to have a haemoglobin A1c (HbA1c) of 38 – 58mmol/mol without complications or the need for treatment. A HbA1c is a blood test which examines your average blood glucose level over the last two to three months and can be used to diagnose type 2 diabetes. A HbA1c of 48 mmol/mol is the diagnostic level for type 2 diabetes for people without glucokinase hyperglycaemia.

This ‘raised’ HbA1c level can cause people with glucokinase hyperglycaemia to be misdiagnosed as gestational diabetes or established diabetes. For people with glucokinase hyperglycaemia, concurrent type 2 diabetes would be diagnosed if the HbA1c was over 58 mmol/mol, rather than the standard 48 mmol/mol.

GCK patient information leaflet
See our GCK Patient Information Leaflets under 'Resources for Patients'

What does GDM mean for patients? Misdiagnosis

During pregnancy, many people will be offered screening for Gestational Diabetes Mellitus (GDM) as undiagnosed GDM can increase the risks for both the pregnant person and their baby. GDM is a commonly occurring pregnancy complication, affecting at least 4-5 in every 100 pregnant people and it is estimated that around 30,000 women/birthing people are diagnosed with this condition every year.

For approximately 1 in 100 (1%) of people diagnosed with GDM, they will have glucokinase hyperglycaemia.

Outside of pregnancy people with glucokinase hyperglycaemia generally do not need any specialist treatment or investigations (such as: medication to lower their blood glucose, blood glucose monitoring, retinal (eye) screening, diabetic foot checks). People with glucokinase hyperglycaemia are at no high risk of developing type 2 diabetes than the rest of the population. 1 in 1000 people have glucokinase hyperglycaemia.

Treatment for glucokinase hyperglycaemia during pregnancy is dependent on whether the baby does or does not also have glucokinase hyperglycaemia.

Why is early diagnosis important?

By correctly identifying glucokinase hyperglycaemia, people can be offered personalised care and avoid possible unnecessary intervention during pregnancy and beyond.

What are we doing?

We are working with maternity diabetes teams across the East of England and East Midlands to provide education and support to introduce and embed the monogenic diabetes clinical pathway initiative into the gestational diabetes pathway. This will increase equitable access to genetic testing across the region.

This project will allow identification of glucokinase hyperglycaemia in pregnancy to become a routine part of antenatal care through building on the routine process of screening for diabetes in pregnancy and strengthen existing structures and pathways.

Who are we working with?

Alongside working with maternity diabetes teams within the region, we are also working with:

  • Genomics England via the National Midwives in Genetics and Genomics (MiGGs) network
  • The NHSE Genomic Medicine Service Alliances
  • Royal Devon University Healthcare NHS Foundation Trust, the global centre of excellence for monogenic diabetes

Meet our team