Scientists identify biomarkers behind sudden infant death

NEW DELHI: Australian researchers have identified what may be the first explanation of why some healthy infants die in their sleep, a condition known as Sudden Infant Death Syndrome (SIDS), one of the leading causes of fatality in children younger than 12 months and an occurrence linked with devastating psychological impact on parents.

At play could be an enzyme called butyrylcholinesterase (BChE), responsible for waking – or arousing -- the brain from sleep in case there is a threat to life, like obstructed breathing. The study found that blood taken from infants who died from SIDS contained significantly less BChE than those that survived. “Babies have a very powerful mechanism to let us know when they are not happy,” lead researcher Carmel Harrington said, according to a statement last week by the Sydney Children’s Hospital, where the team is based. “Usually, if a baby is confronted with a life-threatening situation, such as difficulty breathing during sleep because they’re on their tummies, they will arouse and cry out,” Harrington said. “What this research shows is that some babies don’t have this same robust arousal response.”

For their study, published in the journal eBioMedicine (a part of the The Lancet’s publications), dried blood spot samples taken 2-3 days after birth from 722 babies were analysed. It found that the enzyme was “lower in babies who subsequently died of SIDS compared to surviving controls and other non-SIDS deaths”.

SIDS fatalities occur when a seemingly healthy baby dies unexpectedly in sleep. Their exact share in deaths in India was not immediately available – estimates from decades ago pegged this at a prevalence rate of 3.9 per 1,000 births.