Laynie Dratch, ScM, CGC: There are 2 main types of genetic testing. One is diagnostic genetic testing, and the other is predictive genetic testing. Diagnostic genetic testing refers to when an individual has a clinical diagnosis of some diseases—in this case, ALS [amyotrophic lateral sclerosis]. They undergo genetic testing to see if we can identify a genetic reason for why that disease developed.

Predictive genetic testing, on the other hand, is the testing of an asymptomatic individual who has a known genetic risk for some disease. This is like testing the child or sibling of an individual with ALS who doesn’t have any symptoms but wants to see if they inherited the genetic risk in the family to develop that disease.

A delay in diagnosis can be devastating in terms of our ability to have therapeutic impact. This is going to become increasingly important as genetic therapies that are in trials advance and hopefully become FDA-approved therapies. Even with the therapeutic agents that we have now, the earlier that you can initiate treatment, the better. We want to get to individuals while there’s a chance that we can preserve function for as long as possible, so the earlier diagnosis, the better. There was even debate in the field about how we handle this for individuals who know they’re at risk—based on a known genetic variant— but don’t have symptoms.

There’s going to be a continued evolution in how we think about when treatment should be initiated. But the key theme has been the sooner we can initiate treatment, the better. In a related diagnosis, for patients with spinal muscular atrophy, which affects the motor neurons but typically has childhood onset, it’s increasingly clear that the early initiation of the gene-focused treatment that they have is critical. It can mean the difference between a baby being able to sit up, a baby being able to walk within days or weeks of administration of the drugs. We’ll find the same patterns with ALS: the early initiation of treatment is absolutely important.

Jennifer Roggenbuck, MS, LGC: A delay in a diagnosis can have a significant impact on the patient’s quality of life and survival, so it’s important to get someone with ALS diagnosed and, ideally, to a multidisciplinary clinic. There, we can work with a speech pathologist, an occupational therapist, and social workers to help families meet these various needs. A delay in a diagnosis is unfortunate because it means patients may miss out on some of the interventions we can offer.

Transcript edited for clarity.