A new study has pinpointed an enzyme potentially behind Sudden Infant Death Syndrome, or SIDS.
Researchers from Sydney have found that that low levels of an enzyme called butyrylcholinesterase — responsible for brain arousal — could be what causes babies to die in their sleep for no apparent reason.
Around 200 babies die every year of SIDS in the UK. It is also known as ‘cot death’ and usually happens between the ages of one to four months, up to six months old.
This phenomenon was suspected to be caused by a defect in the part of the brain that controls arousal from sleep and breathing.
The theory was that if the infant stopped breathing during sleep, the defect would keep the child from startling or waking up.
The Sydney researchers were able to confirm this theory by analysing dried blood samples taken from newborns who died from SIDS and other unknown causes. Each SIDS sample was then compared with blood taken from healthy babies.
They found the activity of the enzyme butyrylcholinesterase (BChE) was significantly lower in babies who died of SIDS compared to living infants and other non-SIDS infant deaths.
BChE plays a major role in the brain’s arousal pathway, which would explain why SIDS typically occurs during sleep.
Previously, parents were told that SIDS could be prevented if they took proper precautions such as laying babies on their backs, not letting them overheat and keeping all toys and blankets out of the crib.
The new research indicates some babies are just more susceptible to SIDS, and there’s nothing parents could have done.
The research was led by Dr Carmel Harrington, whose son unexpectedly died as an infant 29 years ago.
She told ABC: ‘Nobody could tell me. They just said it’s a tragedy. But it was a tragedy that didn’t sit well with my scientific brain.
‘These families can now live with the knowledge that this was not their fault.’
Although it sounds alarming, SIDS is very uncommon and the unexplained mortality rate is approximately 1 in 3,000 live births.
While safe sleep practices are still important for protecting infants, many children whose parents took every precaution still died from SIDS.
These parents were left with immense guilt, wondering if they could have prevented their child’s death.
The study also points towards the possibility of ‘identification of infants at risk of SIDS’ prior to death in the form of a screening tests.
The Lullaby Trust, a charity working with bereaved SIDS families, warned the study could ‘downplay the continued importance of the safer sleep advice’.
A spokesperson for the charity said: ‘The findings of this study are interesting and more work needs to be done.
‘We welcome any new SIDS research and hope that it helps us understand more about why apparently healthy babies die without cause.’
They also urged all parents and carers with infants to continue following safer sleep advice to reduce the risk of SIDS occurring.