Repeat expansions are places where the genome has remained stubbornly dark. Long-read sequencing is beginning to illuminate them, and now that new visibility is moving into clinical testing.
Today we’re joined by Simon Sadedin, Head of Clinical Bioinformatics at Victorian Clinical Genetics Services in Australia, and Alex Lindell, Senior Director of Product Marketing at Oxford Nanopore.
Until now, testing for repeat expansions has largely meant building a separate assay for each disorder. A patient might be tested for Fragile X, get a negative result, and then move on to another test, sometimes waiting months at each step. Some repeat expansions have been difficult to test for at all. Simon’s group is trying to replace that serial approach with a single assay covering roughly 60 repeat expansion loci, which is now being submitted for clinical accreditation.
The promise goes beyond simply finding an expansion. Long reads can reveal its length, sequence, methylation and mosaicism, while adaptive sampling makes it possible to target these difficult regions in software rather than building a new wet lab assay for each one.
Some say we are at a new threshold in genomics, where parts of the genome that have remained dark are finally becoming accessible to both discovery and clinical medicine.
