Single-voxel MR spectroscopy and diffusion-weighted MRI in two patients with l-2-hydroxyglutaric aciduria.

l-2-Hydroxyglutaric aciduria is a rare inherited, neurometabolic disorder. The underlying metabolic defect and the pathophysiology of l-2-hydroxyglutaric aciduria have not yet been defined. We present MR spectroscopy and cranial MR imaging findings, including diffusion-weighted sequences in two male siblings (aged 10 and 12 years). MR spectroscopy revealed a multiplet at 2.10-2.50 ppm and two broad peaks at 0.9-1.6 ppm. The multiplet at 2.10-2.50 ppm might have been created by elevated glutamate and glutamine or l-2-hydroxyglutaric acid itself, which has a similar chemical structure to glutamate. Diffusion-weighted images demonstrated increased diffusion of water molecules in the white-matter lesions.