FREQUENCY OF MEDIUM-CHAIN ACYL-COA DEHYDROGENASE-DEFICIENCY G-985-MUTATION IN SUDDEN-INFANT-DEATH-SYNDROME

A small percentage of apparent sudden infant death syndrome (SIDS) vic tims may have an unsuspected metabolic disorder. Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is a disorder of fatty acid oxidation that has been the most common such metabolic disorder found in series of SIDS victims. A single mutation in MCAD deficiency has been recent ly described (G-985) that accounts for approximately 90% of MCAD defic iency mutations. We studied the hypothesis that heterozygosity or homo zygosity for this specific MCAD deficiency mutation might be associate d with SIDS. DNA was extracted from the paraffin-embedded autopsy tiss ues of 67 victims of SIDS in Monroe County, NY who died between 1984 a nd 1989. Using the polymerase chain reaction/NcoI digestion method, we found no G-985 homozygotes and three (4.5%) G-985 heterozygotes. In 7 0 newborn controls, there were no G-985 homozygotes and one (1.4%) het erozygote. Although the frequency of G-985 heterozygotes was slightly greater than in our control group, it was not statistically different. We conclude that the specific MCAD deficiency mutation G-985 is not s trongly associated with SIDS and that MCAD deficiency probably does no t make a significant contribution to the etiology of SIDS.