Sudden infant death syndrome may be due in part to impaired coupling of the neurotransmitter serotonin to receptors in the lower brainstem
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Researchers may have identified the biological mechanism behind sudden infant death syndrome (SIDS). A better understanding of what causes this condition could help scientists develop tests that predict SIDS risk in babies.
SIDS occurs when apparently healthy infants die suddenly in their sleep, usually during the first 6 months of life. It is unknown why it occurs, but it is believed to involve a combination of factors such as baby development and environmental exposures such as smoking.
To learn more, Robin Haynes and colleagues at Boston Children’s Hospital in Massachusetts analyzed the brainstems of 70 infants who died. Of these, 58 died from SIDS and 12 from other causes. Researchers have identified differences in how the neurotransmitter serotonin binds to so-called 5-HT2A/C receptors in the lower brainstem among infants who die of SIDS.
In rodents, these receptors have been associated with protective functions during sleep, such as the ability to respond to low oxygen levels by gasping and waking.
Infants who died of SIDS had reduced binding of serotonin to 5-HT2A/C receptors compared with infants who died of causes other than SIDS, or binding did not increase as expected as infants grew. says Dr Haynes. .
These differences, combined with other biological and environmental factors, such as the infant’s sleeping position, may increase the risk of SIDS, researchers say.
A better understanding of the various mechanisms that can cause SIDS, including underlying genetic abnormalities, could one day help scientists develop tests that predict infant risk, Haynes said. In the meantime, researchers say parents should follow safe sleep protocols, such as placing babies on their backs and keeping blankets away from their heads.
“I think one of the things that’s become clear is that, unlike others, SIDS is not the result of one abnormality in one physiological system, but an interaction,” says Los Angeles. says Thomas Keynes of Children’s Hospital.
The fact that studies found that some infants who died of SIDS did not have increased serotonin binding with age explains why these deaths often occur between the first two and four months of life. It could explain why, he says. Changes in respiratory control.
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