Young Sudden Death & Congenital Cardiovascular Diseases—Why Genetic Testing Matters?

Sudden cardiac death in the young (SCDY) is uncommon, but when it strikes it’s catastrophic and often silent until it’s too late. Global reviews show that congenital and inherited heart conditions are major contributors—making prevention and family screening a public‑health priority.

What is SCDY—and why does it happen?

SCDY typically refers to a sudden cardiac death at ≤35–40 years of age, with many cases linked to undiagnosed cardiomyopathies, channelopathies, aortopathies, or congenital anomalies—even when individuals appeared healthy. When the standard autopsy is negative, the case is classified as sudden unexplained death (SUD); in these scenarios, genetic causes are common and molecular autopsy (post‑mortem genetic testing) can reveal the diagnosis and guide family prevention.

The Hong Kong picture: what local data tells us

A five‑year Hong Kong review in public mortuaries documented 289 young SCD victims; 35% were due to coronary artery disease, 40% to structural heart disease, and 25% were unexplained—a group enriched for Sudden Arrhythmia Death Syndrome (SADS) and related inherited conditions. In a 2017–2021 Hong Kong molecular autopsy cohort (ages 1–40), 11 of 41 decedents carried 13 SCD‑causative variants; genes included DSP, TPM1, TTN, and SCN5A, all well‑known for cardiomyopathies and channelopathies. Family cascade testing identified additional at‑risk relatives; notably, a TPM1 carrier was subsequently diagnosed with hypertrophic cardiomyopathy and could be managed proactively.

Congenital heart disease (CHD): the visible and invisible risks

CHD is among the most common birth defects worldwide, and certain malformations or residual electrical/structural issues can elevate the risk of sudden death in children and young adults—even after repair. Equally important, some high‑risk youths have no visible structural abnormality at all. In SADS, inherited electrical disorders (e.g., Long QT syndrome, Brugada syndrome) can trigger lethal arrhythmias even when the heart looks normal.

Why genetic testing changes the story

Across international and local studies, genetic testing—during life or via molecular autopsy—improves diagnosis and guides early, targeted prevention for families (surveillance, lifestyle counseling, medication, and device therapy when indicated).

Who should consider CVD genetic testing?

• Family history of sudden unexplained death (<40 years).

• Diagnosed cardiomyopathy (e.g., HCM, DCM, ACM) in you or relatives.

• Inherited arrhythmia syndromes (Long QT, Brugada, CPVT).

• Congenital heart disease (repaired or unrepaired) with symptoms or arrhythmias.

• Unexplained fainting, seizures, or palpitations in young people.

Your next step

Talk to a cardiologist or clinical geneticist about cardiovascular genetic testing and family cascade screening. Hong Kong’s recent molecular autopsy programs show that this approach identifies hidden risk and saves lives by enabling early interventions across whole families.

CoGenesis® CVD 先天性心血管疾病基因檢測

FromHK$9,100.00

Buy Now

參考資料

1. Salzillo, C., Sansone, V., & Napolitano, F. (2024). Sudden cardiac death in the young: Review in molecular autopsy. Current Issues in Molecular Biology, 46(4), 3313–3327. https://doi.org/10.3390/cimb46040207[healthyhk.gov.hk]

2. Salzillo, C., Resta, N., Bagnulo, R., & Marzullo, A. (2026). Myocardial bridging and SCN5A variant in young sudden cardiac death. Egyptian Journal of Forensic Sciences, 16, 14. https://link.springer.com/article/10.1186/s41935-025-00499-1[onlinelibr....wiley.com]

3. Kwok, S.-Y., Ho, S., Shih, F.-Y., Cheng, S. S. W., et al. (2024). Molecular autopsy in Chinese sudden cardiac death in the young. American Journal of Medical Genetics A. https://doi.org/10.1002/ajmg.a.63797[link.springer.com]

4. Mak, C. M., Mok, N. S., Shum, H. C., et al. (2019). Sudden arrhythmia death syndrome in young victims: Review and molecular autopsy study. Hong Kong Medical Journal, 25(1), 21–29. https://doi.org/10.12809/hkmj187256[frontiersin.org]

5. Mishra, V., Zaidi, S., Axiaq, A., & Harky, A. (2020). Sudden cardiac death in children with congenital heart disease. Cardiology in the Young, 30(11), 1559–1565. https://doi.org/10.1017/S1047951120003613[dh.gov.hk]

6. Tsuda, T., Fitzgerald, K. K., & Temple, J. (2020). Sudden cardiac death in youths without structural heart disease. Reviews in Cardiovascular Medicine, 21(2), 223–237. https://www.imrpress.com/journal/RCM/21/2/10.31083/j.rcm.2020.02.55