The detection of 3-methylglutarylcarnitine and a new dicarboxylic conjugate, 3-methylglutaconylcarnitine, in 3-methylglutaconic aciduria.

Two patients, diagnosed with 3-methylglutaconic aciduria, who presented with diverse clinical and metabolic manifestations, were studied. Glycine conjugation as a possible detoxification mechanism in these two patients yielded negative results. Carnitine conjugates were however detected. 3-Methylglutarylcarnitine was observed in the urine of both patients, while one of the patients excreted detectable quantities of 3-methylglutaconylcarnitine, a previously unknown metabolite. The presence of this metabolite in urine samples from one patient and the apparent correlation between administered carnitine and the conjugate excretion profile seems to indicate that carnitine may play an important role in future therapeutic programmes.