Skip to main content
Public beta This website is in public beta – please give your feedback.

At a glance:

  • Sudden cardiac death (SCD) at a young age may be caused by inherited cardiac conditions, including cardiomyopathies and inherited arrhythmia syndromes.
  • Post-mortem testing of individuals who have suffered SCD should include an autopsy and may include genetic analysis, which will help identify the cause.
  • Identifying a pathogenic variant within a family can guide clinical management and plays a crucial part in providing access to genomic testing for unaffected family members (cascade genomic testing).
  • If the autopsy shows a normal heart, this is known as sudden arrhythmic death syndrome (SADS). Most SADS deaths are caused by inherited arrhythmia syndromes (for example, Brugada syndrome).
  • Alert! If a genetic cause of SCD is identified, lifestyle modifications, medications and implantable defibrillators can save lives.

Example clinical scenario

A 44-year-old woman attends an appointment. Her husband has just died unexpectedly aged 39 of SCD. His brother also died unexpectedly aged 35, but this happened abroad and no post-mortem was carried out. She has children aged 19, 17 and 15 (also your patients) and she has been advised that they need genomic testing.

Identifying those at risk of a genetic condition

  • The most common cause of young SCD is hypertrophic cardiomyopathy, which has an autosomal dominant inheritance pattern with variable penetrance.
  • Another important cause is arrhythmogenic right ventricular cardiomyopathy, which has an autosomal dominant inheritance pattern with age-dependent penetrance.
  • Inherited arrhythmia syndromes that can cause young SCD include long QT syndrome and Brugada syndrome.
  • Sudden unexpected death in a young person should trigger an autopsy.
  • Some SCD victims may be suitable for post-mortem genomic testing.
  • If an inherited cardiac condition has been identified at autopsy, genomic testing will be targeted to that condition. See the National Genomic Test Directory for further details.
  • If no underlying cause of death is found at autopsy and the SCD remains unexplained, broader genomic testing may be considered in the form of a molecular autopsy.
  • Flags for an underlying genetic diagnosis include:
    • SCD at a young age;
    • multiple (particularly young) SCD events in the family; and
    • a family history of inherited cardiac disease.

What should you do next?

  • If young SCD occurs in a family (particularly if the autopsy shows an inherited cardiac condition or if the SCD remains unexplained after autopsy), first-degree relatives (parents, siblings and children) should be referred to an inherited cardiac conditions service for clinical screening.
  • Referrals to inherited cardiac conditions services should include as much information as possible, and first-degree relatives should be asked to take a copy of their relative’s death certificate and post-mortem report (if a post-mortem was performed) to their appointment.
  • There is no need to arrange clinical tests prior to referral, although a 12-lead electrocardiogram (ECG) can be helpful.
  • If the SCD remains unexplained after autopsy, the National Genomic Test Directory has further referral criteria for genomic testing.
  • If an underlying genetic cause is identified, family members should be referred to clinical genetics services for cascade genomic testing of family members (this is called predictive genomic testing).
  • For information about how to arrange testing in Wales, Scotland or Northern Ireland, see our dedicated Knowledge Hub resource.
  • Information about patient eligibility and test indications were correct at the time of writing. When requesting a test, please refer to the National Genomic Test Directory to confirm the right test for your patient.

Resources

For clinicians

For patients

↑ Back to top
  • Last reviewed: 27/04/2023
  • Next review due: 27/04/2024
  • Authors: Dr Deborah Hipps
  • Reviewers: Dr Rachel Bastiaenen, Dr Asma Hamad, Dr Jude Hayward