Persistent hyperammonemia in two related Morgan weanlings.
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.
McCornico
R S
RS
Department of Food Animal and Equine Medicine, North Carolina State University, College of Veterinary Medicine, Raleigh, USA.
Duckett
W M
WM
Wood
P A
PA
D000596:Amino Acids / Q000097:blood; D000641:Ammonia / Q000097:blood*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001706:Biopsy / Q000379:methods / Q000662:veterinary; D005260:Female; D006734:Horse Diseases / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology; D006736:Horses; D008099:Liver / Q000473:pathology / Q000503:physiopathology; D008111:Liver Function Tests; D008659:Metabolic Diseases / Q000097:blood / Q000150:complications / Q000662:veterinary*; D009422:Nervous System Diseases / Q000209:etiology / Q000503:physiopathology / Q000662:veterinary; D009952:Ornithine / Q000097:blood; D014886:Weaning
D000596:Amino Acids; D000641:Ammonia; D009952:Ornithine