Health condition
PRKAG2 syndrome
PRKAG2 syndrome is a rare inherited glycogen-storage disease of the heart that combines ventricular thickening with electrical abnormalities - pre-excitation, conduction disease and early pacemaker need - and is often mistaken for HCM.
Why trust this guide
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Editorial team
Written by our editorial team from the UK sources listed on each page.
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Sourced from guidance
Checked against current NHS and UK specialist society guidance at the time of review.
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Current for 2026
Reviewed on 2026-09-27 with the next review scheduled for 2027-09-27.
Key points
What matters most, at a glance.
The essentials in plain English - symptoms, when to seek help, who to see and what treatment looks like.
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The combination of a thickened ventricle, pre-excitation and progressive conduction disease should prompt genetic testing
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Inheritance is autosomal dominant, so each child of an affected parent has a one-in-two chance
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Many patients need a pacemaker in early or mid-adult life
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Distinguishing PRKAG2 from sarcomeric HCM and from WPW changes ablation and follow-up decisions
Understanding it
About PRKAG2 syndrome, and what to do next.
Variants in PRKAG2 disturb the cell’s energy-sensing machinery, allowing glycogen to accumulate in heart muscle. The stored glycogen both thickens the walls and creates abnormal electrical connections between atria and ventricles, which is why arrhythmia and conduction problems dominate the clinical picture.
Management is tailored: accessory-pathway-style pre-excitation here often reflects diffuse muscle connections rather than a discrete pathway, so ablation strategies differ, and surveillance anticipates progressive heart block. Gene-panel testing secures the diagnosis and enables family screening. Most people start with their GP, who can refer to a consultant cardiologist at an inherited cardiac conditions (ICC) clinic. In many parts of the UK, routine NHS referrals for this kind of problem currently take 20-45+ weeks, whereas an initial private consultation is typically available within around two weeks.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, see them - and seek urgent care for any emergency symptoms described above.
Frequently asked
Common questions about PRKAG2 syndrome.
Quick, plain-English answers to what people ask us most.
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What is PRKAG2 syndrome?
PRKAG2 syndrome is a rare inherited heart condition causing thickening of the heart muscle (a form of cardiomyopathy) along with abnormal electrical conduction, which can lead to arrhythmias.
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What causes PRKAG2 syndrome?
It's caused by inherited mutations in the PRKAG2 gene, which affects how heart muscle cells manage energy metabolism, leading to abnormal glycogen storage and structural changes in the heart.
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What are the symptoms?
Symptoms can include palpitations, breathlessness, and, in some cases, fainting related to abnormal heart rhythms, along with features of heart muscle thickening seen on cardiac imaging.
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Is PRKAG2 syndrome dangerous?
Yes, it can cause serious heart rhythm problems and heart failure over time, so specialist cardiology follow-up and, where relevant, treatment for arrhythmias are important.
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Is PRKAG2 syndrome hereditary?
Yes, it's inherited in an autosomal dominant pattern, meaning each child of an affected parent has a 50% chance of inheriting the condition.
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Can PRKAG2 syndrome be treated?
Treatment focuses on managing arrhythmias, sometimes including a pacemaker or defibrillator device for significant conduction problems, alongside standard heart failure treatment if the heart's pumping function is affected.
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How is PRKAG2 syndrome diagnosed?
Diagnosis involves an ECG showing characteristic conduction abnormalities, echocardiogram or cardiac MRI to assess heart muscle thickening, and genetic testing to confirm the specific mutation.
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How is PRKAG2 syndrome monitored?
Regular cardiology follow-up, including periodic ECG and imaging, helps monitor for progression of heart muscle changes and arrhythmia risk over time.
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PRKAG2 syndrome vs other inherited cardiomyopathies — what's the difference?
Other inherited cardiomyopathies, such as hypertrophic cardiomyopathy from different gene mutations, can cause similar heart muscle thickening but without the same specific conduction abnormalities seen in PRKAG2 syndrome; genetic testing helps distinguish between them.
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When should I see a specialist, and how quickly can I be seen privately?
See a cardiologist if you have a family history of PRKAG2 syndrome or relevant symptoms such as palpitations or fainting. Private specialist assessment is typically available within about two weeks, faster than standard NHS referral pathways for this rare condition.