San Francisco-based Invitae has developed a genetic test to diagnose spinal muscular atrophy (SMA), the company announced at the March 21-25 American College of Medical Genetics (ACMG) Annual Clinical Genetics Meeting in Phoenix.
SMA is the second leading genetic disorder affecting children in the United States. One in every 10,000 kids has SMA, and one of 50 Americans is a carrier of the genetic mutations leading to this disorder.
Infants develop SMA due to the presence of mutations in the SMN1 gene, which block the production of the SMN protein necessary for proper spinal development and functioning. The lack of SMN kills motor neurons and weakens muscles, making it hard for children to stand up, sit, breathe or swallow. Different copy numbers in a similar gene, SMN2, influence disease severity in patients.
That makes testing SMA patients for both genes a critical step in diagnosing and treating the disease — as well as distinguishing it from other muscular disorders. Knowing the number of copies of SMN2 may predict patient prognosis and help doctors guide treatment choices and participation in clinical studies.
However, as the two genes are similar, tests that accurately differentiate their analysis have not been easy to find.
“Determining SMN2 copy number accurately has, in the past, been a challenge,” Perry Shieh, MD, of the University of California-Los Angeles, said in a news release. “Improvement in the SMN2 copy number assay will provide better diagnostic and prognostic information about SMA patients that will guide clinicians with appropriate disease management.”
The genetic test developed by Invitae allows the identification of mutations and copy number analysis of both genes in a single test. It is now part of the company’s panel of tests to diagnose neuromuscular disorders and can be a reliable measure to diagnose SMA alongside other neurological diseases at no additional cost.
According to its press release, Invitae has secured in-network status with major national health insurance payers. For third-party payers with whom Invitae is out-of-network and for non-contracted institutions, the price per test in a clinical area is $1,500. For patients without insurance coverage or those who don’t meet insurance criteria for coverage, Invitae offers its full test offerings for $475 per test in a clinical area.
“In addition to the use of the Invitae SMA test in the diagnosis of infants and children with early onset neuromuscular disease, the recent development of new therapies directed at SMA is leading to the possible inclusion of SMN1 testing in universal newborn screening panels, which will mean in turn that having an accurate, cost-effective confirmatory test is essential,” said Robert Nussbaum, MD, Invitae’s chief medical officer. “We’re proud to bring this advancement in testing to the SMA community.”