Cobalamin deficiency is a common disorder in Chinese Shar Peis (Shar Peis) and is thus suspected to be hereditary. The objective of this study was to identify a genomic region or locus that cosegregates with the phenotype of cobalamin deficiency in Shar Peis. Serum cobalamin concentrations were measured, and blood for genomic DNA extraction was collected from 14 cobalamin-deficient Shar Peis and 28 Shar Peis with a serum cobalamin concentration in the reference range. The 327 microsatellite markers from the canine minimal screening set 2 and 4 additional markers were amplified by polymerase chain reaction and genotyped by automated capillary electrophoresis. Two microsatellite markers, DTR13.6 (P = 1.4 x 10(-6)) and REN13N11 (P = 1.5 x 10(-5)), both on canine chromosome 13, showed evidence of linkage disequilibrium. These findings indicate that the region of chromosome 13 near these markers should be mapped and closely examined for potential mutations associated with this disease in Shar Peis.