Gene Found to Be Associated with SIDS

Researchers have discovered a positive association between sudden infant death syndrome (SIDS) and the 5-HTT gene, which they say may lead to the ability to identify infants at risk for SIDS. Their discovery was reported in the January 17, 2003 online edition of the American Journal of Medical Genetics.

The study was prompted by previous observations of decreased serotonergic receptor binding in SIDS cases. The 5-HTT gene regulates membrane uptake of serotonin and was therefore considered a likely candidate for SIDS studies. The investigators, from Rush-Presbyterian-St. Luke's Medical Center (Chicago, IL, USA), collected DNA samples from 87 US SIDS cases and from two sets of control subjects. The first set was screened for family history of SIDS and then matched to the SIDS cases for ethnicity and gender. The second set of controls included 33 random DNA samples used to determine population genotype frequencies. For each DNA sample, the 5-HTTLPR polymorphism was genotyped.
The results showed a significant positive association between SIDS and the L/L genotype and between SIDS and the 5-HTT L allele, and a negative association between SIDS and the S/S genetoype. SIDS cases were more likely than controls to have the long allele in the Japanese, Caucasian, and African-American study samples.

"If a larger data set reflects observations similar to those in this report,” the authors conclude, "the serotonergic system will represent a key area for further investigation into the casual basis for SIDS, with the goal of identifying genetic risk factors that will aid in recognizing at-risk individuals who require specialized intervention strategies and in counseling families as to the risk of recurrence.”




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Rush-Presbyterian-St. Luke's Medical Center