Nearly 10 percent of sudden infant death syndrome (SIDS) victims have mutations or variations in genes associated with potentially lethal heart rhythms (arrhythmias), according to two newly published studies involving Vanderbilt researchers.
The findings indicate that arrhythmia-susceptibility genes represent important genetic contributors to SIDS, said Alfred L. George Jr., M.D., senior author on one of the studies. The studies appear in the early online edition of the journal Circulation.
According to the Centers for Disease Control and Prevention, approximately 2,200 deaths each year in the United States are attributed to SIDS, making it the third leading cause of death among all infants, but the leading cause of mortality in infants age 1 month to 1 year. Several behavioral and environmental factors such as prone (stomach) sleeping position and exposure to cigarette smoke are known risk factors. Campaigns to educate parents about these potential dangers may explain the decrease in SIDS since the early 1990s.
However, SIDS continues to be a leading cause of infant mortality in developed countries, and the underlying basis of the condition remains unclear. A popular theory proposes that SIDS occurs because of a combination of risks including abnormal physiological state, environmental factors and developmental vulnerabilities. Genetic factors have also been proposed to be important.
"SIDS is not one disease," said George, the Grant W. Liddle Professor of Medicine and director of the Division of Genetic Medicine. "Multiple conditions can increase the risk of sudden death in an infant. Some have been identified, but many have not."
Anecdotal evidence previously suggested that some SIDS victims carry mutations in genes associated with conditions such as the long QT syndrome (LQTS) that predispose individuals to life-threatening arrhythmias and sudden death. But the proportion of SIDS cases that carry such mutat
Contact: Craig Boerner
Vanderbilt University Medical Center