DETECTION OF INBORN-ERRORS OF FATTY-ACID OXIDATION FROM ACYLCARNITINEANALYSIS OF PLASMA AND BLOOD SPOTS WITH THE RADIOISOTOPIC EXCHANGE-HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD

Sixty-one plasma samples from patients with inborn errors of fatty aci d oxidation and from control subjects were analyzed in a blinded fashi on for acylcarnitines by the radioisotopic exchange-high-performance l iquid chromatographic method. All samples from patients with medium-ch ain acyl-coenzyme A dehydrogenase (MCAD) deficiency (n = 30), some of which hod been stored in a frozen state for several years, showed a pr ominent octanoylcarnitine peak. in all blood spots from 11 patients wi th MCAD deficiency, octanoylcarnitine was also detected. Control plasm a specimens and blood spots contained small amounts of octanoylcarniti ne; however, the octanoylcarnitine/acetylcarnitine ratio differentiate d patients with MCAD deficiency. Longer-chain acylcarnitines were foun d in plasma of all three patients with defects in long-chain fatty aci d oxidation. Plasma and blood spots from a patient with multiple acyl- coenzyme A dehydrogenase deficiency contained C4-acylcarnitine, hexano ylcarnitine, octanoylcarnitine, and decanoylcarnitine. The results sug gest that the method may be highly sensitive in detecting MCAD deficie ncy and other defects in fatty acid oxidation from plasma or blood Spo tS.