Investigating sudden unexpected death in infancy and early childhood.

Sudden unexpected death is one of the most frequent ways of dying in the first year of life after the neonatal period. It is however, much less frequent after the first birthday. Investigations into the cause of death are very important, for a significant proportion of these sudden deaths can be explained only after a thorough investigation. Of the causes identified, infection is the most frequent cause; metabolic disorders and cardiovascular diseases play a role as well, although the proportion of cases is much smaller. There is now evidence that cardiac channel gene mutations also play an important role; however, identification of these conditions relies on costly testing that is not readily or widely available. The physician's role as primary care provider is critical in ensuring that families understand the results of the investigation into their child's death. It is important that everything be done to identify the cause of death so that no such tragedy recurs in the same family.