title: Serum homocysteine and methylmalonic acid concentrations in Chinese Shar-Pei dogs with cobalamin deficiency.
abstract: Cobalamin deficiency is suspected to be hereditary in Chinese Shar-Pei dogs (Shar-Peis), and inherited causes of cobalamin deficiency may affect the cellular processing of cobalamin. In humans, a defect of the two main cobalamin-dependent intracellular enzymes (i.e., methionine synthase and methylmalonyl-CoA mutase) may lead to hyperhomocysteinemia and hypermethylmalonic acidemia. The aim of this retrospective study was to evaluate serum homocysteine (HCY) and methylmalonic acid (MMA) concentrations in cobalamin-deficient Shar-Peis and dogs of six other breeds. Serum samples (n=297) from cobalamin-deficient dogs (Shar-Peis, German Shepherd dogs, Labrador Retrievers, Yorkshire Terriers, Boxers, Cocker Spaniels, and Beagles) were analyzed for serum HCY and MMA concentrations. A Fisher's exact test was used to evaluate if cobalamin deficiency in Shar-Peis is associated with hyperhomocysteinemia. Serum HCY and MMA concentrations were higher in cobalamin-deficient Shar-Peis compared to cobalamin-deficient dogs of the six other breeds (P<0.0001). Hyperhomocysteinemia was associated with cobalamin deficiency in Shar-Peis (P=0.009). In addition, serum HCY and MMA concentrations did not differ between cobalamin-deficient German Shepherd dogs with and without exocrine pancreatic insufficiency (EPI), a potential cause of secondary cobalamin deficiency. These findings suggest that the function of the two intracellular cobalamin-dependent enzymes is impaired in Shar-Peis with cobalamin deficiency.
authors.affiliation: Gastrointestinal Laboratory, Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474, USA. ngruetzner@cvm.tamu.edu
authors.forename: Niels
authors.initials: N
authors.lastname: Grützner
authors.forename: Romy M
authors.initials: RM
authors.lastname: Heilmann
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Stupka
authors.forename: Venkat R
authors.initials: VR
authors.lastname: Rangachari
authors.forename: Katja
authors.initials: K
authors.lastname: Weber
authors.forename: Andreas
authors.initials: A
authors.lastname: Holzenburg
authors.forename: Jan S
authors.initials: JS
authors.lastname: Suchodolski
authors.forename: Jörg M
authors.initials: JM
authors.lastname: Steiner
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000097:blood* / Q000235:genetics / Q000378:metabolism; D004285:Dogs; D020022:Genetic Predisposition to Disease; D006710:Homocysteine / Q000097:blood* / Q000378:metabolism; D008764:Methylmalonic Acid / Q000097:blood* / Q000378:metabolism; D012189:Retrospective Studies; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000235:genetics / Q000662:veterinary*
chemical_list: D006710:Homocysteine; D008764:Methylmalonic Acid
keywords: Cobalamin; Deficiency; Homocysteine; Methylmalonic acid; Shar-Pei dog