Possible genetic link discovered
Sudden infant death syndrome ranks among a parent's greatest fears: a healthy baby put to sleep at night fails to wake up. The fear is compounded because researchers still don't know exactly what causes seemingly healthy babies not to wake up. Sleep position is considered the most likely culprit, but this year, researchers announced there also might be a genetic explanation for SIDS. The gene, 5--HTT, had a long allele characteristic in some of the infants who died of SIDS. An allele is one member of a pair of genes, the hereditary characteristics of human beings. The 5--HTT gene regulates the uptake of serotonin, a chemical in the brain that helps regulate mood, hunger and sleep. SIDS is defined as the unexpected death of an infant that cannot be explained by autopsy or medical history, according to the Centers for Disease Control and Prevention. Most SIDS deaths occur between the ages of 2 and 4 months. "But not every kid who died of SIDS had that long allele, so it's not the whole story," says Dr. Jaen Silvestri, a neonatologist at Rush--Presbyterian--St. Luke's Medical Center in Chicago and one of the researchers. "Still, right now it's trying to figure out what else we need to explore." For now, only one thing is definite, Silvestri says: "The sleeping environment is really important." That message, however, isn't getting out to everyone. In Chicago, African--American infants represented 38 percent of total live births in Chicago in 2001 but accounted for 89 percent of SIDS deaths, according to the Illinois Department of Public Health. And while no white and only four Hispanic infants died of SIDS in 2001, 33 black infants did. Why the racial disparity? "Not everyone is back sleeping," says Nancy Maruyama, a registered nurse and executive director of educational and community services at the SIDS Alliance of Illinois. National SIDS rates have decreased by more than 50 percent since 1992 when the American Academy of Pediatrics launched its "Back to Sleep" campaign to get parents to put their infants to sleep on their backs instead of their stomachs or sides. Black mothers, focus group results show, thought the "Back to Sleep" campaign was "advertising, perhaps for a mattress," says Yvonne Maddox, deputy director of the National Institute of Child Health and Human Development. In 2000, the slogan was changed to "Babies Sleep Safest on Their Backs." Other risk factors for SIDS include overheating, lack of breastfeeding, second--hand tobacco smoke, bed sharing, excessively soft beds, low birth weight, poor prenatal care, young motherhood and poverty. Maruyama, who lost a child to SIDS in 1985, says the good news is that the SIDS death rate in Illinois has decreased 63 percent since 1993. In Chicago, the biggest decreases have occurred in the last three years, adds Shirley Fleming, first deputy commissioner of the Chicago Department of Public Health. "What we are continuing to see is that numbers continue to come down," Fleming says. "But they have come down faster in the white community. "Years of beliefs and understanding about ways to sleep—that takes years to change," she says.
-- Teresa Black and Beth Lawton Medill News Service