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) victims 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 recently described (G-985) that accounts for approximately 90% of MCAD deficiency mutations. We studied the hypothesis that heterozygosity or homozygosity for this specific MCAD deficiency mutation might be associated with SIDS. DNA was extracted from the paraffin-embedded autopsy tissues of 67 victims of SIDS in Monroe County, NY who died between 1984 and 1989. Using the polymerase chain reaction/NcoI digestion method, we found no G-985 homozygotes and three (4.5%) G-985 heterozygotes. In 70 newborn controls, there were no G-985 homozygotes and one (1.4%) heterozygote. 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 strongly associated with SIDS and that MCAD deficiency probably does not make a significant contribution to the etiology of SIDS.