Peer-reviewed veterinary case report
Persistent hyperammonemia in two related Morgan weanlings.
- Journal:
- Journal of veterinary internal medicine
- Year:
- 1997
- Authors:
- McCornico, R S et al.
- Affiliation:
- Department of Food Animal and Equine Medicine · United States
- Species:
- horse
Plain-English summary
Two young Morgan fillies were found to have high levels of ammonia in their blood, a condition known as persistent hyperammonemia, shortly after they were weaned. Despite thorough testing, including blood tests, a liver biopsy, and imaging of the liver, no signs of toxins, developmental issues, or infections were found. The results indicated that the fillies might have a genetic condition similar to one seen in humans called HHH syndrome, which affects how their bodies process certain proteins and leads to high ammonia levels. This condition is caused by a problem with a protein that helps with the breakdown of waste in the liver. Unfortunately, the specific outcome of their treatment is not mentioned in the study.
Abstract
Persistent hyperammonemia was diagnosed in 2 Morgan fillies with clinical signs that developed early in the postweaning period. Diagnostic evaluation, including routine serum chemistries, CBC, liver biopsy, hepatic ultrasonography, liver function test, and necropsy findings did not support a toxic, developmental, or infectious cause. Abnormal serum amino acid and urine orotic acid concentrations suggest that the foals may have had an inherited disorders described in humans as hyperornithinemia, hyperammonemia, and homocitrullinuria (HHH) syndrome. The disorder is thought to be caused by a defective mitochondrial transporter protein, such that ornithine, required for complete urea synthesis, is deficient, thus causing increases in blood ammonia and ornithine concentrations.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/9298483/