Metabolic disease and sudden, unexpected death in infancy.

The prevalence of metabolic disease in infants dying suddenly and unexpectedly is controversial. Most studies have centered on major pediatric institutes with appropriate facilities to study inherited metabolic disease. No studies have been reported from nonacademic centers. We have prospectively studied urine and blood organic and fatty acids from 58 consecutive infant deaths over a 1-year period in nonteaching hospital medical examiners' offices in the state of Illinois for evidence of metabolic disease. One infant was found to have medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, homozygous for the common A985G mutation. One had probable non-A985G MCAD deficiency based on the identification of cis-4-decenoic acid in blood and one had ethylmalonic-adipic aciduria. Thus, we found evidence that inherited metabolic defects are related to unexpected infant death in this population. These disorders are present in a significant minority of infants who probably would have been given the diagnosis of sudden infant death syndrome if they had not undergone metabolic evaluation. We recommend that all infants who have died suddenly and unexpectedly be regarded as high-risk candidates for metabolic disease and that all such deaths be appropriately investigated as part of the routine autopsy procedure.