A defect in intracellular uptake of carnitine has been identified in patients with severe carnitine deficiency. To define the clinical manifestations of this disorder, the presenting features of 15 affected infants and children were examined. Progressive cardiomyopathy, with or without chronic muscle weakness, was the most common presentation (median age of onset, 3 years). Other patients presented with episodes of fasting hypoglycemia during the first 2 years of life before cardiomyopathy had become apparent. A defect in carnitine uptake was demonstrable in fibroblasts and leukocytes from patients. The defect also appears to be expressed in muscle and kidney. Concentrations of plasma carnitine and rates of carnitine uptake in parents were intermediate between affected patients and normal control subjects, consistent with recessive inheritance. Early recognition and treatment with high doses of oral carnitine may be life-saving in this disorder of fatty acid oxidation.
Epilepsy is an important component of ME. The higher incidence of complex I defects in patients with epilepsy suggests a possible relationship between mitochondrial oxidative stress dysfunction and epileptogenic process.
The neuropathologic findings in a 17-year-old boy with ataxia-telangiectasia are described. In agreement with previous reports, pathologic changes were present in the cerebellum, spinal cord, dorsal root ganglia, and straited muscle. The lesions in the spinal cord and dorsal root ganglia were more severe than previously described. Abnormalities were also seen in several brain stem nuclei, including the mesencephalic nucleus of the trigeminus and the substantia nigra. In addition, a small hamartomatous tumor was found in that thalamus.
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