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Abstract #2051

Ornithine Transcarbamylase Deficiency with Persistent Abnormality in Cerebral Glutamate Metabolism

Napapon Sailasuta1, Andrea L. Gropman2, Kent Harris1, Osama Abulseoud3, Brian D. Ross1,4

1Clinical MR Spectroscopy, Huntington Medical Research Institutes, Pasadena, CA, United States; 2Neurology, Children's National Medical Center, Washington D.C., United States; 3University of Southern California, Keck School of Medicine, Los Angeles, CA, United States; 4Rudi Schulte Research Institute, Santa Barbara , CA, United States

Despite effective treatment of hyperammonemia, children and adult survivors of ornithine transcarbamlyase deficiency (OTCD) a frequent enzyme defect of the hepatic urea cycle, exhibit a wide variety of neurological, neuropsychological, neuroimaging and neurochemical abnormalities. Most recently, in addition to proton MRS abnormalities o sub-clinical hepatic encephalopathy, residual deficits in glutamate neurotransmission have been identified by non-invasive 13C MRS studies after loading tests with 1-13C and 2-13C glucose. The results point to a hitherto unrecognized defect in cerebral glucose metabolism. Successful therapies of this new lesion may improve long term neurological outcome for this and other defects of urea synthesis.