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Fatal infantile form of muscle phosphofructokinase deficiency

S Servidei, E Bonilla, R G Diedrich

    Neurology
    |November 1, 1986
    PubMed

    Insights

    A rare infantile syndrome involving limb weakness and seizures was linked to a severe deficiency in phosphofructokinase (PFK) activity. Despite normal PFK protein levels, enzyme function was critically impaired, suggesting a unique genetic cause.

    Area of Science:

    • Biochemistry
    • Genetics
    • Neurology

    Background:

    • Infantile syndromes can present with complex neurological and muscular symptoms.
    • Phosphofructokinase (PFK) deficiency is a rare metabolic disorder affecting glycolysis.
    • Understanding the molecular basis of PFK deficiency is crucial for diagnosis and potential therapies.

    Observation:

    • A 7-month-old infant presented with limb weakness, seizures, cortical blindness, and corneal opacifications, succumbing to respiratory failure.
    • Muscle biopsies revealed mildly increased glycogen and significantly reduced PFK enzyme activity (1.4% of normal).
    • In vitro studies confirmed a metabolic block in anaerobic glycolysis.

    Findings:

    • Immunological assays indicated normal levels of PFK protein (cross-reacting material) despite the severe enzyme deficiency.
    • The patient's brain exhibited characteristics of neuroaxonal dystrophy.
    • These findings suggest a variant form of PFK deficiency potentially caused by a distinct genetic defect.

    Implications:

    • This case highlights a potential new genetic variant of phosphofructokinase deficiency.
    • It underscores the importance of enzyme activity assays over protein levels for diagnosing certain metabolic disorders.
    • Further research into the genetic underpinnings of this PFK deficiency variant is warranted.

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