Children with two copies of the common genetic variation have a 24-fold increased risk of sudden death as infants. One out of nine African Americans carries one copy of the common variant. One copy does not appear to increase risk for infants.
"The common polymorphism alone does not cause SIDS," said Steven Goldstein, M.D., Ph.D., professor and chairman of pediatrics at the University of Chicago and director of the study. "Our findings suggest, however, that it renders infants vulnerable to environmental challenges -- such as a long pause in respiration -- that are tolerated by children without the mutation."
"The hope," he added, "is that findings like this may one day allow us to intervene. We might screen to identify children at high risk and teach parents how to lessen the likelihood of secondary challenges. We have already begun to evaluate drugs that may mitigate the risk."
SIDS -- the sudden and unanticipated death of an infant with no detectable lethal disorder -- is the leading cause of infant deaths in the United States, representing nearly one-third of deaths between one month and one year of age. African Americans have three times greater risk of SIDS than Caucasians and six times the risk of Hispanics or Asians, suggesting an important role for genetics.
The researchers studied the genes in tissue collected from 133 African-American infants with a diagnosis of SIDS after autopsy. They compared results with tissue samples from 1,056 African-American adults with no known health problems.
Source:University of Chicago Medical Center