Researchers develop a single DNA test for a quicker and more accurate diagnosis of over 50 genetic diseases.
In a recently published study, researchers at the Garvan Institute of Medical Research in Sydney provided evidence on the accuracy of a newly developed DNA test. According to the study, the single DNA test can detect more than 50 genetic diseases. Moreover, the test was not only accurate but also provided a quicker diagnosis than current tests.
Short tandem repeats (STRs) are short, repeated DNA sequences, mostly 2-6 base pairs long. Although the DNA sequence can vary in length, unusually long or ‘expanded’ STR alleles are responsible for causing several heritable disorders. These include Huntington’s disease, fragile X syndrome, myotonic dystrophies, hereditary cerebellar ataxias, amyotrophic lateral sclerosis (ALS) and many more. Due to limited genetic testing methods and diverse pathogenic STR expansion alleles, diagnosing these diseases is often challenging. Moreover, current tests rely on doctors individually testing for the different genes in a trial-and-error method. Thus, taking years to reach an accurate diagnosis; something researchers call the ‘diagnostic odyssey’. Therefore, there is a need for better diagnostic methods for such diseases.
They are often difficult to diagnose due to the complex symptoms that patients present with, the challenging nature of these repetitive sequences, and limitations of existing genetic testing methods.
Dr Ira Deveson, senior au
Avoiding the ‘Diagnostic Odyssey’
The team of researchers used Nanopore sequencing for scanning a patient’s genome. This allowed them to scan for unusually long repeats within the 40 genes implicated in these genetic diseases. Not only is the new test smaller and cheaper than existing tests, it also allows a faster diagnosis.
This new test will completely revolutionise how we diagnose these diseases, since we can now test for all the disorders at once with a single DNA test and give a clear genetic diagnosis, helping patients avoid years of unnecessary muscle or nerve biopsies for diseases they don’t have, or risky treatments that suppress their immune system.
Dr. Kishore Kumar, co-author of the study
The team is currently working on making the test available in pathology labs.
Although STR-expansion disorders are incurable, study authors believe that a single DNA test will provide a quicker diagnosis. Thus, helping doctors prepare for any disease complications before time and likely slow down the progression of the disorder.
Reference:
Igor Stevanovski et al, Comprehensive genetic diagnosis of tandem repeat expansion disorders with programmable targeted nanopore sequencing, Science Advances (2022). DOI: 10.1126/sciadv.abm5386. www.science.org/doi/10.1126/sciadv.abm5386
