Invitae unveils new spinal muscular atrophy test

Invitae tests for both the SMN1 and SMN2 genes in its new test for spinal muscular atrophy, combining diagnostic and prognostic information.

Invitae boosted its genetic testing menu with a new test for the diagnosis of spinal muscular atrophy, the second-leading genetic disease in infants.

The test provides “significant improvements” over current testing methods, Invitae said. Spinal muscular atrophy (SMA), like cystic fibrosis, is an autosomal recessive disorder, meaning that a child must inherit two copies of an abnormal gene for the disease to develop. It affects motor neurons in the spinal cord, causing weakness in voluntary muscles.

Most SMA cases are caused by a mutation in the SMN1 gene, blocking the production of the SMN protein, which is vital in maintaining motor neurons. Patients have varying amounts of the related gene, SMN2, which plays a role in the severity of an individual’s disease. About one in 10,000 infants develop SMA, while about one in 50 people are carriers of the disease.

Testing for SMN1 provides a diagnosis and differentiates the disease from other neuromuscular conditions, while testing for SMN2 can help doctors come up with a prognosis and guide treatment decisions.

“However, due to the similarities between the two genes, testing is technically challenging and reliably accurate tests have not previously been widely available,” Invitae said in a statement.

Invitae’s SMA test uses next-generation sequencing and bioinformatics to evaluate sequence changes and copy numbers of both SMN1 and SMN2 in a single test. It is available in Invitae’s neuromuscular and neuropathy testing panels or as a standalone test.

"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," said Invitae Chief Medical Officer Robert Nussbaum, in the statement.