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[Pyruvate dehydrogenase deficiency in a child with persistent lactic acidosis]

E Dworzak, H Grunicke, H Berger

    Journal of Clinical Chemistry and Clinical Biochemistry. Zeitschrift Fur Klinische Chemie Und Klinische Biochemie
    |June 1, 1985
    PubMed

    Insights

    A new form of pyruvate dehydrogenase deficiency was found in a child with lactic acidosis and myasthenia. This enzyme defect impairs energy production, leading to severe symptoms and muscle abnormalities.

    Area of Science:

    • Biochemistry
    • Cell Biology
    • Pediatric Neurology

    Context:

    • Persistent lactic acidosis in children can indicate underlying metabolic disorders.
    • Pyruvate dehydrogenase deficiency is a rare inherited condition affecting cellular energy metabolism.
    • Myasthenia and growth retardation can be symptoms of mitochondrial dysfunction.

    Purpose:

    • To characterize a novel pyruvate dehydrogenase deficiency in a pediatric patient.
    • To investigate the biochemical and cellular basis of the patient's symptoms.
    • To correlate enzyme activity with clinical presentation and muscle pathology.

    Summary:

    • A 10-year-old child with lactic acidosis, myasthenia, and growth retardation exhibited defective pyruvate dehydrogenase (PDH) activity in leukocytes and muscle.
    • The PDH defect was characterized by reduced stimulation of catalytic activity by phosphoprotein phosphatase in vitro and lack of response to exercise in vivo.
    • Biochemical analysis revealed elevated pyruvate, lactate, and alanine, with decreased citrate, consistent with PDH deficiency.
    • Muscle biopsy showed enlarged mitochondria with abnormal cristae, indicative of mitochondrial dysfunction.

    Impact:

    • Identifies a previously undescribed form of pyruvate dehydrogenase deficiency.
    • Provides insight into the pathophysiology of PDH deficiency and its clinical manifestations.
    • Highlights the importance of PDH assessment in children with unexplained lactic acidosis and neurological symptoms.
    • Contributes to understanding mitochondrial disorders and their impact on muscle function.

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