SIDS demystified: Brain defect one of the culprits

A study conducted by the researchers at Children's Hospital, Boston has revealed that abnormalities in the serotonin system in the brains of infants make them more vulnerable to sudden infant death syndrome (SIDS). The study has been published in the November issue of the Journal of the American Medical Association.

The study confirms that SIDS is a biological disease and that there is a brain defect that contributes significantly to it. Explaining the defect, the researchers told that the babies who died of SIDS had flaws in their brainstem.

The serotonin system is located in an area of the brainstem called the medulla oblongata, and regulates body functions like heart rate, breathing, blood pressure and temperature regulation.

If the brain's serotonin system is working normally, it signals the baby to wake up and move his head to get fresh air. In cases where the serotonin system is not working properly, it does not send the right signals to the rest of the body.

The new research included tissue samples from 31 babies who died of SIDS, and 10 babies who died of other causes. The researchers found that brainstems from babies affected by SIDS contained more nerve cells that make and use serotonin than the brainstems of the other infants.

However, there were fewer serotonin receptors in SIDS babies' brains. As a result they could not process the brain chemical as they should.

The study has its own limitations such as small sample size and the under-representation of black infants. Moreover, experts believe that the ultimate cause of SIDS would be multi-factorial as genetics and environment also play a vital role.

Two other previous studies have also found serotonin-receptor defects in case of SIDS babies. The present study is a step farther in terms of focusing on the role of serotonin and SIDS. It also gives a specific place to look into in future research.