title: Serum cobalamin, urine methylmalonic acid, and plasma total homocysteine concentrations in Border Collies and dogs of other breeds.
abstract: OBJECTIVE
  To determine reference ranges for serum cobalamin (Cbl), urine methylmalonic acid (uMMA), and plasma total homocysteine (tHcys) concentrations and to compare values for healthy control dogs with values for Border Collies (BCs), a breed in which hereditary cobalamin deficiency has been identified.
  
  
  METHODS
  113 BCs, 35 healthy control dogs fed a typical diet, and 12 healthy dogs fed a bone and raw food diet exclusively.
  
  
  METHODS
  Urine and blood samples were obtained from each dog and Cbl, uMMA, and tHcys concentrations were determined.
  
  
  RESULTS
  Reference ranges for Cbl (261 to 1,001 ng/L), uMMA (0 to 4.2 mmol/mol of creatinine), and tHcys (4.3 to 18.4 μmol/L) concentrations were determined. Four BCs had a Cbl concentration lower than the assay detection limit (150 ng/L); median uMMA and tHcys concentrations in these dogs were 4,064 mmol/mol of creatinine and 51.5 μmol/L, respectively. Clinical abnormalities included stunted growth, lethargy, anemia, and proteinuria. Abnormalities improved after administration of cobalamin. Of the 109 healthy BCs with Cbl and tHcys concentrations within reference ranges, 41 (37.6%) had a high uMMA concentration (range, 5 to 360 mmol/mol). Results for dogs fed raw food were similar to those for control dogs.
  
  
  CONCLUSIONS
  Hereditary cobalamin deficiency is a rare disease with various clinical signs. The finding of methylmalonic aciduria in healthy eucobalaminemic BCs and BCs with clinical signs of Cbl deficiency was surprising and indicated these dogs may have defects in intracellular processing of Cbl or intestinal Cbl malabsorption, respectively. Studies investigating Cbl absorption and metabolic pathways are warranted.
authors: Clinic for Small Animal Internal Medicine, University of Zurich, Zürich, Switzerland.
authors: Sabina
authors: S
authors: Lutz
authors: Adrian C
authors: AC
authors: Sewell
authors: Beat
authors: B
authors: Bigler
authors: Barbara
authors: B
authors: Riond
authors: Claudia E
authors: CE
authors: Reusch
authors: Peter H
authors: PH
authors: Kook
mesh_terms: D000592:Amino Acid Metabolism, Inborn Errors / Q000188:drug therapy / Q000503:physiopathology / Q000662:veterinary*; D000818:Animals; D015415:Biomarkers / Q000097:blood / Q000652:urine; D002849:Chromatography, Gas / Q000662:veterinary; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004283:Dog Diseases / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology*; D004285:Dogs; D005260:Female; D006710:Homocysteine / Q000097:blood*; D049449:Luminescence; D008297:Male; D008764:Methylmalonic Acid / Q000652:urine*; D012016:Reference Values; D013045:Species Specificity; D014805:Vitamin B 12 / Q000097:blood* / Q000627:therapeutic use; D014806:Vitamin B 12 Deficiency / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology / Q000662:veterinary*
chemical_list: D015415:Biomarkers; D006710:Homocysteine; D008764:Methylmalonic Acid; D014805:Vitamin B 12