Researchers have found a previously unknown genetic mutation in two young people with juvenile-onset amyotrophic lateral sclerosis (ALS).

In a study published in the Journal of Neurology, Neurosurgery and Psychiatry, an international group of researchers discussed two patients who were unrelated to each other and presented with “early-onset progressive proximal and distal muscle weakness, oral fasciculations, and pyramidal signs.”

Both patients had a mutation of the novel de-novo SPTLC2 gene, which changes the “production of sphingolipids, a fat type that is essential from brain function,” according to a Dec. 18, 2023, announcement from the Miller School of Medicine at the University of Miami.

Stephan Züchner, M.D., Ph.D., the senior author of the study, said in the Miami announcement, “This is the first time we’ve shown that mutations in the gene SPTLC2 are a cause for ALS. Now, having identified this genetic anomaly, labs can begin looking for potential therapies.”

Researchers originally looked for SPTLC2 mutations in the genomic sequences from 700 ALS patients, and found those mutations in two patients with early-onset muscle weakness. According to a Jan. 5 report from ALS News Today, one of those patients was diagnosed with juvenile-onset ALS at age 14. The second patient began showing signs of ALS by age 10.

The National Institutes of Health defines juvenile onset of ALS as onset before age 25. About 40 percent of juvenile-onset ALS is genetically related, compared to just 10 percent of ALS in adults.