March 17, 2022 — Diseases that affect the nervous system can be some of the most difficult conditions for doctors to diagnose.
Many conditions can cause similar symptoms, but two people with the same condition could have different symptoms, which can make the cause of the symptoms hard to pinpoint. Delays in diagnosing the condition mean that people go longer without the treatment they need.
But now, a new DNA test is solving that problem for more than 50 genetic diseases that affect the nervous system.
The new test covers Huntington’s disease, Lou Gehrig’s disease, fragile X syndrome, epilepsy, and various other neurological diseases that are passed on genetically from parents to children.
These diseases are collectively known as short-tandem repeat expansion disorders, which means that very long DNA sequences that repeat over and over in a person’s genes are causing problems.
The new test uses a technique called nanopore sequencing, which scans a patient’s DNA looking for 37 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. This identifies what condition the person has.
Though none of these conditions has a cure, early diagnosis helps patients prepare for future symptoms and helps doctors manage complications.
Before this test, doctors and patients had to rely on less accurate tests.
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 conditions we don’t yet know about.