PREVALENCE OF MEDIUM-CHAIN ACYL-COENZYME A DEHYDROGENASE-DEFICIENCY IN THE SUDDEN-INFANT-DEATH-SYNDROME

Disorders of fatty acid beta-oxidation have been suggested as playing a significant role in the sudden infant death syndrome (SIDS). To eluc idate the role of medium-chain acyl-coenzyme A dehydrogenase (MCAD) de ficiency in SIDS, we identified all cases of SIDS occurring in Los Ang eles County between January 1986 through December 1991. A total of 130 4 SIDS deaths were identified; tissue samples were collected in 1236 c ases (94.8%). Extraction of DNA was successful in 1224 tissue samples (93.9%), which were examined for the presence of the G985 mutation, id entified as occurring in more than 88% of affected cases of MCAD defic iency. Three heterozygotes and no homozygotes were identified; this in cidence does not differ from that reported in the general population. Review of the pathologic specimens from the identified heterozygotes a nd from 18 ethnic-, age-, and sex-matched control subjects revealed si gnificant fatty infiltration of all organs examined in one of the thre e heterozygotes and in none of the control subjects. We conclude that MCAD deficiency does not play a significant role in the causation of S IDS.