United States researchers have found a potentially lifesaving clue towards understanding sudden infant death syndrome (SIDS).
- Across Australia SIDS still claims 130-150 cases a year
- A third of SIDS infants had very high levels of serotonin in the blood
- Findings could lead to a screening program for babies
The syndrome is the leading cause of post-neonatal infant mortality, and is defined as the sudden death of an infant less than one year of age.
After decades of study, the underlying cause of death in those infants has remained a mystery.
But Dr Robin Haynes, principal pathology associate at Boston Children’s Hospital and Harvard University researcher, said a study she has co-published in Proceedings of the National Academy of Sciences could be an important step in solving the puzzle.
“What we’ve found when we looked at SIDS deaths was a subset that had elevated levels of serotonin in the serum,” she said.
“So this is the first indication that a problem with serotonin might be contributing to SIDS.
“Currently there is no good, consistent marker that either shows a SIDS death at autopsy, or predicts a SIDS risk in infants.”
Karen Waters, a sleep physician and University of Sydney researcher, said the finding was a major breakthrough.
“It’s quite exciting,” Professor Waters said.
Dr Waters said the finding could eventually form the basis of a new screening program to determine which infants are more at risk of SIDS.
“Obviously there’s more to be done, and we have to look and see in a whole group of babies what the levels are like and find out how many have these high levels,” she said.
“But if we can find a marker that would tell us which babies are at risk, then it gives us the possibility of intervening before they die.”
Serotonin abnormalities might be key marker: researcher
In their study, Dr Haynes and her fellow Harvard researchers compared two populations of deceased infants — one for whom the cause of sudden death was clear, and a second for whom it remained a mystery.
Building on earlier research by one of her co-authors Dr Hannah Kinney, Dr Haynes said she and her team focused on serotonin abnormalities in the brain cells of SIDS victims.
Serotonin is important for a number of functions, including breathing, arousal during sleep and heart rate.
“So what we were hoping to find here was a bio-marker that you can look at in a living infant, and so you can determine whether they have serotonin problems within the brain stem,” she explains.
The study found, on autopsy, that more than 30 per cent of infants whose cause of death was unclear had elevated levels of serotonin.
Dr Haynes and Dr Waters both said that finding would now inform further research.
“SIDS is probably a group of different things — not all babies are necessarily exactly the same in terms of what caused the SIDS,” Dr Waters said.
“But we’ve been looking for some kind of marker potentially that would identify babies at risk, rather than after they had died, and this is a promising finding.”
Dr Haynes said the challenge now was to replicate her team’s finding with a bigger sample of SIDS cases.
“Our datasets are a good size for SIDS, but relatively small in terms of research as a whole,” she said.
Finding could spur more research in Australia
While SIDS is much less common than it used to be, it still claims the lives of dozens of babies in Australia each year.
Dr Waters said she estimated the sudden deaths of between 130 and 150 infants each year in Australia were not known, and SIDS remained the leading cause of death for infants under one year of age.
The key breakthrough in the fight against SIDS came in the 1980s, when researchers linked babies sleeping on their stomachs with otherwise unexplained deaths.
But Dr Waters said more research was needed, and the Harvard breakthrough might focus researchers attention on SIDS again.
“Research into SIDS has sort of dropped off since the rate has reduced,” she said.
“But it still claims lives and there’s quite a push from parents who’ve been affected by SIDS to promote the research again.
“So I think the fact that we’re getting closer to finding answers is a reason for pushing that we continue this research.”