Genetic Testing Solves Mystery of Teens' Sudden Deaths: University of Auckland Research

The University of Auckland's Groundbreaking Genetic Discovery

A team of researchers from the University of Auckland has unveiled a significant advancement in understanding sudden cardiac death among young people, identifying a previously overlooked genetic culprit through cutting-edge genetic testing. Published on April 21, 2026, in the European Heart Journal, the study reveals that repeat expansions in the DMPK gene—typically associated with myotonic dystrophy type 1 (DM1)—can trigger fatal heart arrhythmias in teenagers and young adults without obvious muscle symptoms.

Led by Dr. Polona Le Quesne Stabej at Pūtahi Manawa, the University of Auckland's Centre of Research Excellence for heart health, the findings stem from whole-genome sequencing of historical DNA samples from affected families. This work not only provides closure for grieving whānau but also calls for expanded genetic screening protocols across New Zealand's healthcare system.

The research highlights how advanced technologies like Oxford Nanopore long-read sequencing can detect complex genetic variants missed by conventional short-read methods, underscoring the University of Auckland's leadership in precision medicine.

Sudden Cardiac Death: A Hidden Threat to New Zealand Youth

Sudden cardiac death (SCD) claims up to 90 lives annually in Aotearoa New Zealand among those under 40, with approximately one-third remaining unexplained even after thorough postmortem examinations. These tragedies often strike healthy, active teenagers during exercise or emotional stress, leaving families devastated and clinicians searching for answers.

In the young, SCD frequently results from inherited cardiac conditions such as channelopathies or cardiomyopathies, but standard genetic panels identify causes in only 20-27% of cases. The University of Auckland study bridges this gap by pinpointing DMPK repeat expansions as a novel contributor, potentially accounting for 1-2% of unexplained cases based on their cohort analysis.

New Zealand's Cardiac Inherited Diseases Group (CIDG), founded in 2000 by Professor Jon Skinner from Auckland City Hospital and the University, has long advocated for systematic genetic evaluation post-SCD. This latest research from Pūtahi Manawa strengthens their mission, emphasizing equity for Māori and Pacific communities disproportionately affected by heart disease.

Unraveling the DMPK Gene's Role in Myotonic Dystrophy Type 1

Myotonic dystrophy type 1 (DM1), the most common adult muscular dystrophy, arises from CTG trinucleotide repeat expansions in the 3' untranslated region (3'UTR) of the DMPK gene on chromosome 19. Normal alleles have 5-34 repeats; pathogenic expansions range from 50 to over 1,000, with severity correlating to length—mild (50-150), classic (100-1,000), and congenital (>1,000).

These expansions produce toxic RNA that sequesters splicing factors, leading to mis-splicing of cardiac ion channel genes like SCN5A, which disrupts heart rhythm. While conduction defects (e.g., AV block) are classic in symptomatic DM1 adults, the Auckland study shows young carriers can suffer ventricular tachyarrhythmias and SCD without neuromuscular signs or ECG abnormalities.

In DM1, sudden death accounts for 15% of mortality, often exercise-triggered in adolescents. Prevalence is about 1:2,100 births in New Zealand, yet subclinical cardiac risk in expansion carriers demands proactive screening.

Revolutionary Methods: Long-Read Sequencing at the Forefront

Traditional short-read sequencing struggles with repetitive regions like DMPK 3'UTR, often yielding ambiguous results. The University of Auckland team employed Oxford Nanopore Technologies (ONT) long-read sequencing, which reads thousands of bases continuously, accurately sizing expansions.

• Whole-genome sequencing (WGS) on historical postmortem samples from three families.
• Bioinformatics analysis by Dr. Zoe Ward identified heterozygous pathogenic expansions.
• Validation via triplet-primed PCR (TP-PCR) using AmplideX kits.
• Cohort screening: 115 unexplained SCD cases (1-35 years), detecting 1.7% incidence (95% CI 0.3-4.6%).

Performed at the Liggins Institute, this approach exemplifies the University of Auckland's Precision Medicine Initiative, reducing genome sequencing costs from billions to thousands of dollars.Read the full study in European Heart Journal.

Real Families, Real Impact: Case Studies from the Research

The study details three families where SCD struck without prior warning:

• Family 1 (NZ Māori): Proband II-2 died at 13 during exercise; siblings II-5 (16, exercise) and II-3 (18, argument). Normal autopsies; father had right ventricular abnormalities and left bundle branch block. Pathogenic DMPK expansions confirmed; two surviving siblings now have implantable cardioverter-defibrillators (ICDs).
• Family 2 (Australia): Proband II-1 SCD at 27 (exercise); nephew III-1 congenital DM1 death at 4 days. Expansions: >1,400 (congenital), >150 (mother), >120 (proband), >60 (grandfather).
• Family 3 (Australia): 16-year-old male SCD during exercise; 254-repeat expansion.

These cases reveal exercise as a trigger, with subtle clues like clumsiness or cataracts emerging retrospectively.

Transforming Screening and Prevention in New Zealand

The findings advocate routine DMPK testing in unexplained young SCD investigations, potentially preventing further tragedies through family cascade screening. In New Zealand, where equity gaps persist—Māori have higher SCD rates—this could save lives via implantable devices or lifestyle advice.

A Māori Kaitiaki Rōpu ensured cultural safety, recognizing DNA as taonga linked to whakapapa. Professor Cris Print notes: "This increase in biological understanding allows clinical practice to change and saves lives."University of Auckland news release.

Integration into CIDG protocols could identify at-risk relatives early, aligning with national heart health strategies.

Pūtahi Manawa: Powering Cardiovascular Research at Auckland

Pūtahi Manawa, funded by the Tertiary Education Commission, drives equity-focused heart research for Māori, Pacific, and women. This DMPK study exemplifies their precision medicine approach, leveraging the University of Auckland's world-class facilities like the Liggins Institute.

Director Professor Daniel Pinto dos Santos emphasizes community partnerships, training emerging researchers in genomics and bioinformatics—vital for New Zealand's higher education landscape.

International Collaborations Elevate NZ Higher Education

Partnering with Australia's Centenary Institute, the study bridges trans-Tasman efforts. Assoc. Prof. Richard Bagnall's validation underscores shared registries' value. Such alliances boost NZ universities' global standing, attracting funding and talent.

For aspiring researchers, opportunities abound in Auckland's cardiac genetics programs.Centenary Institute perspective.

Challenges, Future Outlook, and Training the Next Generation

Challenges include access to long-read tech and interpreting modifiers (e.g., MYL3 variants). Future: Larger cohorts via national registries; AI-enhanced bioinformatics.

University of Auckland trains PhD students and postdocs in these fields, fostering careers in genetic cardiology. Professor Jon Skinner: "Thank you doctor, I don’t have to blame myself anymore"—families' relief fuels innovation.

Photo by Google DeepMind on Unsplash

Expert Insights: Voices from the University of Auckland

Dr. Le Quesne Stabej: "Our findings suggest this genetic change may be an overlooked cause... recommend checking DMPK." Genetic counsellor Saraya Hogan (Ngāti Hako): "DNA is taonga—our whakapapa."

This research positions Auckland as a hub for life-saving genomics.