Sudden infant death syndrome: a testable hypothesis and mechanism

The Sudden Infant Death Syndrome (SIDS) is the most frequent cause of death in infants aged between one month and one year, yet its cause remains unknown. The present hypothesis is that most infants who die of SIDS have an abnormality of the catecholaminergic system, possible genetically determined, which results in a decreased thermogenic response to cold, owing to a deficiency in noradrenaline (NA), which eventually results in severe hypothermia. A series of complex, but interrelated reactions of the infant to the hypothermia and its consequences leads to death. The final mechanism of regulatory failure involves a deterioration of cardiorespiratory function resulting from hypoxia, metabolic acidosis and hypoglycemia. The etiology of "near miss" for SIDS is also unknown. It is postulated that these infants have a similar but milder deficiency which may be due, in part, to genetic factors. Determinations of central and peripheral catecholamines in "near miss" and normal infants will be performed to test this hypothesis.