A new study has revealed that infants who die of the Sudden Infant Death Syndrome, or SIDS, have an abnormality of the serotonin (5-hydroxytryptamine [5-HT]) in their brainstem, that ends up affecting responses to breathing and carbon dioxide, in addition to temperature, blood pressure and heart rate.

"These functions may be compromised during sleep if a baby is lying face down and rebreathing carbon dioxide," said lead study author Hannah C. Kinney, MD. Dr. Kinney is serving at the Harvard Medical School and Children's Hospital Boston in Massachusetts.

The recent findings seem to add more evidence to the speculation that SIDS, which is the "unexplained death of an infant within a mere year of birth, is the direct result from lower levels, instead of an excess, of medullary 5-HT.

"We call this a perfect storm. You have a baby with the underlying vulnerability but that becomes unmasked when the baby is asleep and when the baby undergoes stress", said Dr. Kinney.

Details of the study have been published in the February 3 issue of the Journal of the American Medical Association.