Genetic diseases, especially rare inherited conditions, can be difficult and time-consuming to diagnose. Traditionally, doctors tested one gene at a time or used limited gene panels, often leading to long delays—sometimes called a “diagnostic odyssey.” A newer method, short-read whole genome sequencing (srWGS), reads nearly all of a person’s DNA at once, offering a faster and more comprehensive approach.
A large national initiative in Denmark, led by the Danish National Genome Centre, evaluated how well this technology works in real-world healthcare. Between 2021 and 2024, over 2,300 patients suspected of having genetic diseases were tested using srWGS across multiple medical specialties.
Overall, the test provided a clear genetic diagnosis in about 20% of patients—meaning 1 in 5 individuals received an explanation for their condition. However, success varied widely depending on the type of disease. For example, genetic causes were identified in up to 60% of patients with skin disorders, but only about 6% of children with cancer. This variation highlights that genome sequencing is more useful for some conditions than others.
Importantly, the program demonstrated that large-scale genome sequencing can be integrated into routine healthcare. Advances in technology also reduced costs significantly during the study period, making the test more accessible. Denmark’s model—combining government support, expert clinical guidelines, and public-private funding—helped ensure fair access to testing across patient groups.
The study also emphasized the importance of selecting the right patients for testing. Careful clinical evaluation before sequencing improves the likelihood of finding meaningful results. At the same time, many patients still remain undiagnosed, suggesting that newer technologies, such as long-read sequencing, and better data sharing may further improve outcomes in the future.
In summary, this Danish initiative shows that whole genome sequencing can be a practical and scalable first-line diagnostic tool. While not universally effective, it significantly improves diagnosis for many patients and represents a major step forward in personalized medicine.
References
Faergeman, S.L., Andreasen, L., Becher, N. et al. Short-read genome sequencing at population scale: diagnostic insights from 2317 patients. Eur J Hum Genet (2026). https://doi.org/10.1038/s41431-026-02089-8
