MRI and MRS in HMG-CoA lyase deficiency

3-Hydroxy-3-Methylglutaryl coenzyme A lyase (HMG-CoA) deficiency is a rare inborn error of leucine catabolism. The disease is characterized by recurre nt episodes of metabolic acidosis, hyperammonemia without ketosis, hypoglyc emia, lethargy, hepatomegaly, and seizures. This study has evaluated the ma gnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) fi ndings of three patients with HMG-CoA deficiency. The common findings on al l of the MRI scans were multiple, coalescent, marked lesions in periventric ular white matter and arcuate fibers, most prominently in frontal or periat rial regions that were superimposed on diffuse, slightly hyperintense subco rtical white matter signal. Involvement of the caudate nucleus and the dent ate nucleus were observed in the reported patients. MRS studies by both STE AM and PRESS spectra of all patients revealed a decrease in N-acetylasparta te and elevation in both myoinositol and choline, A pathologic peak at 1.33 ppm, which is compatible with lactate, and a particular peak at 2.42 ppm i n all patients were also found. The combination of both MRI and MRS finding s could be considered as being specific in patients with HMG-CoA lyase defi ciency. (C) 1999 by Elsevier Science Inc. All rights reserved.