Fatal infantile form of muscle phosphofructokinase deficiency.

We studied a girl with an infantile syndrome of limb weakness, seizures, cortical blindness, and corneal opacifications; she died at age 7 months of respiratory failure. There was no consanguinity or family history of neuromuscular diseases. Histochemical and biochemical studies of muscle showed mildly increased glycogen content and markedly decreased PFK activity (1.4% of the normal mean). Anaerobic glycolysis in vitro confirmed the metabolic block. Immunofluorescence and immunotitration by ELISA using monoclonal antibodies against subunit M of PFK showed a normal amount of cross-reacting material. The brain showed typical features of neuroaxonal dystrophy. This variant of PFK deficiency may be due to a distinct genetic defect.