Acylcarnitines in plasma and blood spots of patients with long-chain 3-hydroxyacyl-coenzyme A dehydrogenase defiency

The acylcarnitines in plasma and blood spots of 23 patients with proven def iciency of long-chain 3-hydroxyacylcoenzyme A dehydrogenase were reviewed. Long-chain 3-hydroxyacylcarnitines of C-14:1, C-14, C-16 and C-18:1 chain l ength, and long-chain acylcarnitines of C-12, C-14:1, C-14, C-16, C-18:2 an d C-18:1 chain length were elevated. Acetylcarnitine was decreased. In plas ma, elevation of hydroxy-C-18:1 acylcarnitine over the 95th centile of cont rols, in combination with an elevation of two of the three acylcarnitines C -14, C-14:1 and hydroxy-C-16, identified over 85% of patients with high spe cificity (less than 0.1% false positive rate). High endogenous levels of lo ng-chain acylcarnitines in normal erythrocytes reduced the diagnostic speci ficity in blood spots compared with plasma samples. The results were also d iagnostic in asymptomatic patients, and were not influenced by genotype. Tr eatment with diet low in fat and high in medium-chain triglyceride decrease d all disease-specific acylcarnitines, often to normal, suggesting that thi s assay is useful in treatment monitoring.