Neurological disorders can be some of the most difficult conditions to diagnose. Symptoms are similar for multiple different conditions, and sometimes they vary a lot between patients, which can make the diagnosis hard to pinpoint. Delays mean that individuals go longer without the treatment they need. But now, a new DNA test is solving that problem for more than 50 genetic neurological and neuromuscular diseases.
Among the conditions covered by the new test are Huntington’s disease, Lou Gehrig’s disease, fragile X syndrome, myoclonic epilepsy, and various hereditary muscular or motor neuron diseases.
These disorders are collectively known as short-tandem repeat expansion disorders. Inherited from parents, the name refers to the common factor causing these problems—exceptionally long DNA sequences that repeat over and over in a person’s genes.
The new test uses a technique called nanopore sequencing, which scans a patient’s genome looking for 37 different genes known to be involved with short-tandem repeat expansion disorders. When the test spots the genes, it checks whether they’re part of these long, repetitive sequences and what those sequences are, which then identifies what condition the person has.
Though none of these conditions currently has a cure, early diagnosis allows doctors to manage complications that can arise and prepare for future symptoms.
Before this test, doctors and patients had to rely on less accurate genetic screening. The new approach costs less than $750 and uses technology about the size of a stapler. It can also identify new repetitive sequences, which could lead to discovering new conditions we aren’t yet aware of.