Proton MR spectroscopy of nonketotic hyperglycinemia

Proton magnetic resonance spectroscopy (MRS) can noninvasively detect brain metabolites in vivo. A girl with the neonatal type of nonketotic hyperglycinemia was studied by MRS using a long-echo-time point-resolved technique. The proton spectrum from a volume of 15 x 15 x 15 mm cube located in her left parietal white matter exhibited a glycine signal at 3.5 ppm. Subsequent measurements (3 months to 2 years of age) showed a time course of glycine/creatine ratio similar to the changes of the glycine levels in the blood and cerebrospinal fluid. Our findings suggest that MRS is a noninvasive diagnostic tool useful in monitoring the brain glycine level directly in patients with nonketotic hyperglycinemia.