The syndrome sudden infant death, that is, the death of an apparently healthy infant before the first year of life, remains unexplained. In their publication in the journal “Journal of Neuropathology & Experimental Neurology”, scientists link this syndrome to biological causes.

Sudden infant death syndrome appears to occur when babies are sleeping. Although rare, it is the leading postnatal infant death in the United States today, occurring in 103 of 100,000 live births annually. Despite national public health campaigns promoting safe infant sleep environments in the 1990s in the US, case rates have remained the same over the past three decades.

Investigators, led by Robin Hines from Children’s Hospital Boston, looked at biological material from infants who died between 2004 and 2011.

The findings of their research lead to the conclusion that a biological abnormality in some infants it makes them vulnerable to death under certain circumstances.

Specifically, they found that the serotonin receptor 2A/C is altered in SIDS, and previous research in rodents has shown that signaling of this receptor protects the brain’s oxygen status during sleep.

Scientists believe that SIDS occurs when three things happen together:

  1. The infant is in a critical period of cardiorespiratory development during the first year,
  2. Copes with an external stressor, such as a face-down sleeping position or sharing a bed with another person,
  3. It has a biological abnormality that makes it vulnerable to breathing challenges during sleep.

However, the researchers note that much work remains to determine the consequences of abnormalities in this serotonin receptor.