An international team of researchers led by the National Institutes of Health (NIH) and the Uniformed Services University (USU) have identified a new form of amyotrophic lateral sclerosis (ALS) that starts presenting in early childhood.

In a May 31 news announcement, researchers called this new form of ALS “unique,” not only because of its childhood onset, but also because the children being studied showed a slower progression of symptoms than typically seen in patients with adult-onset ALS.

The team of scientists were studying 11 children who were “medical-mystery patients”: children with baffling sets of symptoms that hadn’t yet been diagnosed. What researchers discovered was a new type of ALS that was linked to a gene called SPTLC1, which is part of the fat-production system in the human body.

Carsten Bönnemann, M.D. — a senior investigator at the NIH’s National Institute of Neurological Disorders and Stroke, and a senior author of the study, which was published in Nature Medicine — said of the discovery, “ALS is a paralyzing and often fatal disease that usually affects middle-aged people. We found that a genetic form of the disease can also threaten children. Our results show for the first time that ALS can be caused by changes in the way the body metabolizes lipids.

“We hope these results will help doctors recognize this new form of ALS and lead to the development of treatments that will improve the lives of these children and young adults. We also hope that our results may provide new clues to understanding and treating other forms of the disease.”

The ALS Association noted that ALS typically affects people in middle age, with 55 years being the average age of onset. The Mayo Clinic said just five to 10 percent of ALS patients inherited the disease. The cause of ALS is unknown in the rest of the ALS patient population.

And while ALS in adults is known to advance rapidly, the children in the study saw their ALS progress more slowly. The children experienced the significantly weakened or paralyzed muscles that adults with ALS have, but by the time the study concluded, the children had lived with ALS from five to 20 years. On average, the children began presenting with early symptoms of ALS at age 4.

In comparison, the ALS Association says that while person with ALS has different experiences, the average survival time for an adult newly diagnosed with ALS is three years, while about 20 percent live for five years.

Payam Mohassel, M.D., an NIH clinical research fellow and lead author of the study, said, “These young patients had many of the upper and lower motor neuron problems that are indicative of ALS. What made these cases unique was the early age of onset and the slower progression of symptoms. This made us wonder what was underlying this distinct form of ALS.”