An inborn error of metabolism leading to fatal
neurologic disease, severe development delay, and ectopia lentis in children.
Infants often present with acute hemiplegia. Clinically manifested by ataxic
gait, generalized dystonia, and choreoathetosis. Confirmed by the presence
of sulfite in the urine (“strip-test”).
Sulfite Oxidase Deficiency.
Autosomal recessive inheritance.
Genetic defect in sulfite oxidase, the enzyme
converting sulfite to sulfate, resulting in the accumulation of sulfite and
decreased secretion of inorganic sulfate. The excess sulfite is partially
converted to thiosulfate and to S-sulfocysteine, and also combined with the
aldehyde groups. This may lead to poor cross-linking of collagen and
Clinical and biochemical features. Blood sulfite level
is low. Urine collection shows increased sulfite and decreased sulfate
excretion. Cultured fibroblast enzyme study shows decreased sulfite oxidase
Patient usually presents in early infancy with
infantile acute hemiplegia, hypotonia, hypertonia, generalized dystonia,
seizure, progressive choreoathetoid movement, ataxia, myoclonus, and
progressive cerebral palsy. The finding of dislocated lens on
ophthalmological examination is highly suspicious. Course of disease
usually follows a rapid deterioration and is often fatal in early childhood,
although a milder course has also been described.
Assess neurological function from medical
history and physical examination. The respiratory status should be assessed because
there is a potential risk of aspiration and pneumonia. General history, examination,
chest radiograph, and arterial blood gas analysis should be obtained.
No reported case. Patient may not be
cooperative because of the mental retardation. Potential risk of aspiration
pneumonia in severe cases.
There are no known implications.
Shih V, Abrams I, Johnson JL, et al: Sulfite oxidase deficiency:
Biochemical and clinical investigations of a hereditary metabolic disorder
in sulfur metabolism. N Engl J Med