Lower levels of protein-like orexin in the brain found in babies who died from Sids is the first potential biological breakthrough for cot death

This article is more than 3 years old

This article is more than 3 years old

The first evidence of a biological explanation for newborns dying suddenly in their sleep may have been found by a group of researchers investigating the brain.

Researchers at the Royal Alexandra hospital for children at Westmead say they have discovered babies who die from sudden infant death syndrome (Sids) have greatly decreased levels of a certain brain protein-like neuropeptide, known as orexin, responsible for regulating sleep arousal.

It is hoped the research could eventually lead to babies being screened for low levels of orexin.

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Such a test would not be available for at least another decade, however, and parents still need to follow the Sids prevention guidelines, experts caution.

There are many well known and evidence-based environmental risk factors related to Sids, such as smoking, excessive bedding and stomach sleeping.

Dr Rita Machaalani, the sleep unit manager at Westmead, said there was now evidence that Sids was caused by a biological condition in an area of the brain responsible for sleep regulation.

A cohort study of more than 27 Sids cases and 19 controls found the level of orexin was 20% lower in the brains of those babies who had died from Sids.

“That seems to indicate that these babies may have had some defect in the message that says this baby should arouse during their sleep time but it didn’t get through to do so,” Machaalani said.

Machaalani said her team was now conducting research to find the mechanism responsible for this reduction in orexin, which has previously been implicated in sleep disorders in adults.

Medical researcher and associate professor Alexandra Martiniuk from the George institute for global health at the University of Sydney, said the potential to screen was huge.

But orexin could be just “one of many” causes of Sids, Martiniuk added.

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“I have read a lot of coroner reports of children who have died of SIDS and there are these other risk factors,” she said. “They do often state that they found the child lying face down or face embedded between mattress and something else.”

Martiniuk said Sids could be the result of a combination of biological and environmental factors, such low levels of orexin and bad sleeping habits.

“It will remain to be seen whether you need a loading of risk factors to have a bad outcome of death.

“But certainly it’s a huge breakthrough because in my knowledge of Sids there hasn’t been anything biological like that before, it has always been environmental risk,” she said.