Modifiable risk factors, sleep environment, developmental physiology and common polymorphisms: Understanding and preventing sudden infant deaths

Unexpected death in infancy may be a consequence of recognisable pathophysiological processes, or may remain unexplained after thorough investigation. We review the appropriate investigations that should be performed after unexpected infant deaths, and the recent changes to UK law that will make such investigations mandatory from 2008. Current knowledge of the epidemiology and pathophysiology of unexpected infant deaths, together with knowledge of infant developmental physiology leads to an emphasis on the importance of a range of potential gene–environment interactions occurring in vulnerable infants at vulnerable stages of their development.