New Blood Test Could Accelerate Diagnosis of Rare Genetic Disorders in Newborns

A newly developed blood test offers the potential to significantly speed up the diagnosis of rare genetic disorders in infants, with researchers hailing it as a breakthrough in reducing the lengthy and often invasive diagnostic processes currently faced by many families.

Published in the journal Genome Medicine, the study describes a method developed by a team at the University of Melbourne that supplements conventional genomic testing with a proteomic analysis of blood cells. The approach allows clinicians to examine the effects of numerous genetic mutations simultaneously, with results obtainable in as little as three days.

Rare genetic conditions – which include diseases such as cystic fibrosis and mitochondrial disorders – can be difficult to diagnose. Despite advances in whole-genome sequencing, current methods typically yield a diagnosis in only 30–50% of suspected cases. Those who remain undiagnosed often embark on a so-called “diagnostic odyssey”, involving months or even years of further tests, some of which require invasive procedures such as muscle biopsies performed under general anaesthesia.

Dr David Stroud, co-author of the study, said: “Genomic testing has revolutionised rare disease diagnosis but still leaves a significant number of patients without answers. Many of these patients then undergo a series of further investigations, often involving invasive tests, to try to determine which of the many genetic variants may be responsible.”

The new technique analyses the proteins found in specific blood cells, comparing them to those present in healthy individuals. Since genes encode proteins, abnormalities at the genetic level often result in defective or missing proteins. By identifying such anomalies, researchers are better able to determine which genetic mutations are likely to be pathogenic.

Professor David Thorburn, also of the University of Melbourne and co-author of the study, stated that the new approach increased diagnostic yields. “Genomics is the frontline test and it can solve the diagnosis in about 30-50% of patients suspected of a rare disease. We think a single proteomic test can increase that diagnostic yield to 50–70%.”

The researchers report that their method outperformed current gold-standard diagnostic techniques for mitochondrial diseases, and succeeded in delivering diagnoses where genomic analysis alone had failed. It also demonstrated advantages in speed and cost-effectiveness. While traditional methods can take weeks or even months, this proteomic approach can produce results within days.

The technique requires only a small sample – as little as 1ml of blood from a newborn – in contrast to current methods that often involve obtaining tissue from a muscle biopsy.

Although the study focused on mitochondrial disorders, the researchers believe the method could be extended to cover approximately half of the estimated 7,000 known rare diseases. Further validation will be required to confirm its broader applicability.

Dr Stroud noted that the new test is not specific to any one disease type, making it a more versatile tool. “That not only makes it more cost-effective, but it also means patients could avoid unnecessary further testing,” he said. “This has obvious benefits to both the patient and healthcare system.”

Beyond aiding in diagnosis and potential treatment, timely identification of a rare genetic disorder can also assist parents in family planning. Where a condition has a hereditary basis, early diagnosis opens the door to options such as pre-natal genetic testing in future pregnancies.

The research has been welcomed by other experts in the field. Professor Michal Minczuk, a mitochondrial genetics specialist at the University of Cambridge, who was not involved in the study, described the development as “a very significant step forward in diagnostic practices”.

He added: “This could greatly enhance patient care by expanding the tools available for clinicians and researchers in genomic medicine.”

Professor Robert Pitceathly, of the UCL Queen Square Institute of Neurology, agreed. “The next step is broader validation and integrating this technology into NHS diagnostic services to improve patient outcomes.”

The University of Melbourne team plans to further refine the test, expand its applicability across a broader spectrum of diseases, and explore its integration into standard diagnostic workflows. The researchers remain optimistic that the method will contribute to faster, less invasive, and more accurate diagnoses for many families confronting the uncertainty of rare genetic disease.

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