New study finds genetic link to some SIDS cases

Oct. 11 (UPI) -- A genetic anomaly may be responsible for some cases of Sudden Infant Death Syndrome, which kills more than 3,000 toddlers annually, according to a study released Friday.

The study by University of Washington researchers, published in Nature Communications, examined the impact of mitochondrial tri-functional protein deficiency, a possibly fatal cardiac metabolic disorder caused by a genetic mutation in the gene HADHA.

Researchers said babies with the genetic anomaly can't metabolize the lipids found in milk, and die suddenly of cardiac arrest when they are a few months old.

The Centers for Disease Control and Prevention says about 3,500 babies in the United States die suddenly and unexpectedly each year. Sudden unexpected infant deaths include SIDS, accidental suffocation in a sleeping environment and other deaths from unknown causes.

"There are multiple causes for sudden infant death syndrome," Hannele Ruohola-Baker, associate director of the University of Washington's Institute for Stem Cell and Regenerative Medicine, said in a statement.

"There are some causes which are environmental. But what we're studying here is really a genetic cause of SIDS. In this particular case, it involves a defect in the enzyme that breaks down fat."

With the deficiency, the heart cells of affected infants cannot convert fats into nutrients properly. That leads to a build-up of unprocessed fatty material that can disrupt heart functions.

"If a child has a mutation, depending on the mutation, the first few months of life can be very scary as the child may die suddenly," said Jason Miklas, a postdoctoral fellow at Stanford University. "An autopsy wouldn't necessarily pick up why the child passed but we think it might be due to the infant's heart stopping to beat."

While there is no cure for the mutation, Ruohola-Baker said the discovery could open new ways such as screenings to spot issues that could lead to SIDS.