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Carnosinase deficiency: a new variant with high residual activity
Pediatric Research
|April 1, 1980
Summary
This study identifies a new variant of carnosinase deficiency in a young male with severe neurological impairment. The condition is characterized by persistent carnosinuria and reduced carnosinase activity, suggesting a potential link to neurological symptoms.
Area of Science:
- Biochemistry
- Genetics
- Neurology
Background:
- Plasma carnosinase deficiency is a rare metabolic disorder.
- This condition is associated with neurological deficits.
Observation:
- A 12-year-old male presented with profound intellectual disability, spastic quadriparesis, optic atrophy, and peripheral neuropathy.
- Amino acid analysis revealed persistent carnosinuria without detectable carnosinemia.
- The patient exhibited significantly reduced plasma carnosinase activity compared to controls and his family members.
Findings:
- The patient showed increased carnosine excretion after L-carnosine loading, indicating impaired metabolism.
- Measurable urinary 1-methylhistidine increased with an anserine diet.
- Reduced carnosinase activity was also observed in the patient's liver and sural nerve, with nerve histology showing axonal degeneration.
Implications:
- This case represents a potential new variant of carnosinase deficiency.
- The findings suggest carnosinuria may be associated with, but not necessarily causal of, severe neurological symptoms.
- Further research is needed to elucidate the precise relationship between carnosinase deficiency and neurological manifestations.
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