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Bilateral infantile cataractogenesis in a patient with deficiency of complex I, a mitochondrial electron transport
T A Ciulla1, K North, O McCabe
1Department of Ophthalmology, Harvard Medical School, Boston, Mass, USA.
Insights
Infants with complex I deficiency, a mitochondrial disorder, can develop progressive cataracts. Early ophthalmic evaluation is crucial for identifying and managing these vision-threatening cataracts in affected infants.
Area of Science:
- Biochemistry
- Ophthalmology
- Genetics
Background:
- Mitochondrial disorders can present with diverse clinical manifestations.
- Complex I deficiency is a common inherited metabolic disorder affecting the electron transport chain.
Observation:
- A 5-month-old infant with confirmed complex I deficiency presented with severe lactic acidosis and progressive bilateral cataracts.
- Ophthalmic examination revealed completely opaque nuclear sclerotic cataracts, leading to loss of fixation and red reflex.
Findings:
- Cytologic analysis and electron microscopy of lens aspirate showed increased intracellular glycogen and swollen mitochondria.
- This case represents the first reported association between complex I deficiency and infantile cataracts.
Implications:
- Early ophthalmic screening is recommended for infants diagnosed with respiratory chain enzyme defects.
- Infantile cataracts may warrant investigation for underlying metabolic disorders, including mitochondrial diseases, especially in cases of unexplained neurological symptoms or metabolic acidosis.
Abstract:
Progressive bilateral cataracts developed in infancy in a 5-month-old girl with deficiency of complex I, a mitochondrial electron transport chain enzyme. In the newborn period, she had severe lactic acidosis and the diagnosis of complex I deficiency was confirmed by mitochondrial respiratory chain assay on muscle biopsy. By 5 months, she had completely opaque nuclear sclerotic cataracts, with loss of fixation and the red reflex. She underwent bilateral, sequential cataract extraction. The lens aspirate was submitted for cytologic analysis and electron microscopy, which revealed increased intracellular glycogen and swollen mitochondria. To our knowledge the association of complex I deficiency with cataracts in infancy has not been reported previously. The diagnosis of a respiratory chain enzyme defect in infancy is an indication for early ophthalmic evaluation to identify cataracts that may result in visual loss. Conversely, the recognition of cataracts in infants with unexplained neurologic disease or metabolic acidosis may necessitate further evaluation for metabolic etiologies, including mitochondrial disorders.