Bruce A. Barshop

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Deficiency of mitochondrial DNA polymerase gamma activity was found in a patient with mtDNA depletion and Alpers' syndrome. Metabolic evaluation revealed fasting hypoglycemia, dicarboxylic aciduria, and reduced activity of the electron transport chain in skeletal muscle. The patient died in early childhood of fulminant hepatic failure, refractory epilepsy,(More)
We report a family with a heterogeneous group of neurologic disorders associated with the mitochondrial DNA G8363A transfer ribonucleic acid (RNA)Lys mutation. The phenotype of one child in the family was consistent with autism. During his second year of life, he lost previously acquired language skills and developed marked hyperactivity with toe-walking,(More)
BACKGROUND Among patients with ethylmalonic aciduria, a subgroup with encephalopathy, petechial skin lesions, and often death in infancy is distinct from those with short-chain acyl-coenzyme A dehydrogenase deficiency or multiple acyl-coenzyme A dehydrogenase deficiency. The nature of the molecular defect in this subgroup is unknown, and the source of the(More)
MR imaging in seven patients (4 days to 38 months old) with nonketotic hyperglycinemia showed age-related findings of progressive atrophy and delayed myelination. Parenchymal volume loss was found as early as 4 days after birth and increased in severity with increasing age to 27 months. Both supratentorial and infratentorial volume loss were present in the(More)
Diabetic kidney disease is the leading cause of ESRD, but few biomarkers of diabetic kidney disease are available. This study used gas chromatography-mass spectrometry to quantify 94 urine metabolites in screening and validation cohorts of patients with diabetes mellitus (DM) and CKD(DM+CKD), in patients with DM without CKD (DM-CKD), and in healthy(More)
We used exome sequencing to identify the genetic basis of combined malonic and methylmalonic aciduria (CMAMMA). We sequenced the exome of an individual with CMAMMA and followed up with sequencing of eight additional affected individuals (cases). This included one individual who was identified and diagnosed by searching an exome database. We identify(More)
Mass spectrometry-based metabolomics is a rapidly growing field in both research and diagnosis. Generally, the methodologies and types of instruments used for clinical and other absolute quantification experiments are different from those used for biomarkers discovery and untargeted analysis, as the former requires optimal sensitivity and dynamic range,(More)
BACKGROUND Ornithine transcarbamylase (OTC) deficiency presents most commonly with neonatal hyperammonemic coma. The gene is on the X chromosome, but the disease may manifest as a dominant trait. Mutations that lead to later-onset presentations may lead to life-threatening disease and may be unrecognized, particularly when the first clinical disease occurs(More)
The etiology of Rett syndrome (RS) remains a mystery. The clinical phenotype has similarities to that of patients with mitochondrial defects of oxidative metabolism. There is evidence of lactate and pyruvate elevations in blood and CSF in some patients. Over the last 10 years we have studied girls with RS looking for evidence of a defect in oxidative(More)
PURPOSE 3-Methylcrotonyl-CoA carboxylase deficiency (MCCD) is an autosomal recessive disorder of leucine catabolism that has a highly variable clinical phenotype, ranging from acute metabolic acidosis to nonspecific symptoms such as developmental delay, failure to thrive, hemiparesis, muscular hypotonia, and multiple sclerosis. Implementation of newborn(More)