Sudden Infant Death Syndrome (SIDS) is the leading cause of death among infants in the first year of age. The more known definition of SIDS is the sudden unexpected death of an infant less than 1 year of age, with onset of the fatal episode apparently occurring during sleep, that remains unexplained after a thorough investigation, including performance of a complete autopsy and review of the circumstances of death and the clinical history. Despite the success of the “Back to Sleep” campaigns to reduce the risks introduced worldwide, the frequency of SIDS (striking one infant every 750-1,000 live births) has not significantly declined in the last years. Sudden Intrauterine Unexplained Death Syndrome (SIUDS), referring to fetuses that die unexpectedly, particularly in the last weeks of gestation, without any cause even after a complete autopsy, including examination of the placental disk, umbilical cord and fetal membranes, has a six-eightfold greater incidence than that of SIDS. Even if the pathogenetic mechanism of these deaths has not yet been determined, the neuropathology seems to be a consistent substrate in both SIUDS and SIDS. Subtle common developmental abnormalities of brainstem nuclei checking the vital functions have been highlighted, frequently related to environmental risk factors, such as cigarette smoke, air and water pollution, pesticides, food contamination, etc. Exogenous toxic factors can in fact interact in complex ways with the genetic constitution of the infant leading to polymorphisms and/or mutations of specific genes (as |