{"topic_id":"companion_breed_health_komondor_omia957_dog","category":"companion-breed-health","context":"---\nlicense: permission_granted\ntopic_id: companion_breed_health_komondor_omia957_dog\ncategory: companion-breed-health\ntitle: \"Komondor — Intestinal cobalamin malabsorption, AMN-related (hereditary; OMIA-verified breed predisposition)\"\nlang: en\nsource: \"OMIA (Online Mendelian Inheritance in Animals, University of Sydney) breed-specific hereditary-disorder record, saved verbatim to source_file; C1 substring-verified. Pulled 2026-08-02 from local OMIA database dump.\"\nsource_file: pdf-raw/breed-health/komondor_omia957_957.txt\ndate_parsed: 2026-08-02\ntokens_estimated: 855\nverification:\n  method: substring_match\n  claims: 9\n  passed: 9\n  date: 2026-08-02\nrecovered: false\npath: companion-breed-health/companion_breed_health_komondor_omia957_dog/01_companion_breed_health_komondor_omia957_dog.md\nsource_document: \"OMIA — Online Mendelian Inheritance in Animals (University of Sydney)\"\ncitation:\n  authority: \"OMIA — Online Mendelian Inheritance in Animals (University of Sydney)\"\n  title: \"Komondor — Intestinal cobalamin malabsorption, AMN-related (hereditary; OMIA-verified breed predisposition)\"\n  url: \"https://omia.org/OMIA000565/9615/\"\n  retrieved: \"2026-08-02\"\n  ref: \"OMIA breed-specific hereditary-disorder records (omia.org), derived from local OMIA database dump; dataset: https://doi.org/10.25910/2AMR-PV70\"\n  doc_type: \"academic animal-genetics database (breed-specific disorder entries)\"\n  needs_review: false\n\n\n# Komondor — Intestinal cobalamin malabsorption, AMN-related (hereditary; OMIA-verified breed predisposition)\n\nSource: first-hand OMIA (University of Sydney) breed-specific hereditary-disorder record, saved verbatim to `source_file`; every claim below is a C1 byte-substring of it.\n\n## Claims\n\n- `Breed: Komondor (Dog)`\n- `Disorder: `\n- `Mode of inheritance: Autosomal recessive`\n- `Summary: Intestinal cobalamin malabsorption is a metabolic disorder characterized by failure to thrive, neutropenia, decreased serum cobalamin (Cbl), and nonregenerative anemia. Other signs include chronic inappetance, megaloblastic changes of the bone marrow, methylmalonic aciduria, and homocysteinemia. It occurs in the giant schnauzer, Australian shepherd, border collie, Hungarian komondor, and beagle. In giant schnauzers and Australian shepherds intestinal cobalamin malabsorption is due to absence of receptors for the intrinsic factor-Cbl complex at the brush border of enterocytes in the ileum. A specific defect has not yet been demonstrated in other breeds. The mode of inheritance is autosomal recessive. The two known causative mutations are a deletion in AMN in the giant schnauzer, and a nucleotide substitution in AMN in the Australian shepherd. Tests are available to detect the known causative mutations. Parents and siblings of affected dogs should be tested. Breeding of affected dogs is not recommended. Carriers should be bred only to clinically normal dogs demonstrated to be non carriers. Entry edited by John C. Fyfe, D.V.M., Ph. D. Intestinal cobalamin malabsorption can be caused by mutations in the AMN gene (this entry) or by mutations in the CUBN gene [a href=../../../../../../OMIA001786/9615/OMIA:001786-9615/a].`\n- `Clin feat: Signs begin around 6 to 12 weeks of age, and include failure to thrive and chronic inappetance. Affected animals also demonstrate neutropenia with hypersegmentation, nonregenerative anemia with anisocytosis and poikilocytosis, megaloblastic changes of the bone marrow, decreased serum Cbl concentrations, methylmalonic aciduria, and homocysteinemia. These animals have normal renal function, but low-molecular weight urinary protein excretion (Fyfe et al., 1991).`\n- `Defect: yes`\n- `Pathology: In normal dogs, Cbl is ingested in the diet and binds to intrinsic factor, a glycoprotein made by the gastric mucosa and the pancreatic duct epithelium. The complex of intrinsic factor (IF) and Cbl is absorbed through binding receptors on enterocytes in the distal jejunum and ileum. Signs of intestinal cobalamin malabsorption are due to absence of receptors for the IF-Cbl complex at the brush border (Fyfe et al., 1991). Affected dogs have one of two demonstrated mutations in the gene coding for amnionless, a protein that complexes with cubilin to ensure apical membrane localization of IF-Cbl receptors in enterocytes. It also regulates endocytic functions. Without functional amnionless, the IF-Cbl receptors do not localize to the brush-border, and dogs cannot absorb cobalamin (Fyfe et al., 2003). Dogs are born with cobalamin stores, but they are rapidly used up during postnatal growth unless replaced from the diet. This is when signs become apparent (Fyfe et al., 1991).`\n- `Control: Parents and siblings of affected dogs should be tested. Breeding of affected is not recommended. Carriers should only be bred to tested dogs that are not carriers.`\n- `Gen test: A DNA test for the disorder is included in the OFA's list at http://www.offa.org/dna_alltest.html, which directs enquiries to PennGen at the University of Pennsylvania (http://research.vet.upenn.edu/Default.aspx?alias=research.vet.upenn.edu/penngen).`\n## Associated gene(s)\nDerived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.\n- Gene: Entrez Gene ID 3429615 (no symbol in OMIA GeneSynonym) — OMIA Phene_Gene\n- OMIA molecular-genetics note: By adopting a comparative positional cloning approach, having established AMN as a very strong comparative positional candidate gene (see Mapping section above), He et al. (2005) showed that the causative mutation in Giant Schnauzers is an \"in-frame deletion of 33 nucleotides in exon 10 of AMN . . . [namely] c.1113_1145del\"; the causative mutation in Australian shepherds is \"a G&gt;A transition at…\n\n## Causal variant(s)\nDerived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.\n- Variant: allele D; chromosome 8; pathogenicity class 1 — OMIA Variant / Variant_Phene\n\n## Evidence (references)\nDerived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.\n- 1991. Inherited Selective Intestinal Cobalamin Malabsorption and  Cobalamin Deficiency in Dogs. Pediatric Research — PubMed:PMID1848001 — OMIA Phene_Article / Article\n- 1991. Defective Brush-Border Expression of Intrinsic Factor- Cobalamin Receptor in Canine Inherited Intestinal Cobalamin  Malabsorption. Journal of Biological Chemistry — PubMed:PMID1999430 — OMIA Phene_Article / Article\n- 2000. Persistent cobalamin deficiency causing failure to thrive in a juvenile beagle. Journal of Small Animal Practice — PubMed:PMID11023127 — OMIA Phene_Article / Article\n- 2003. Canine Imerslund-Grasbeck syndrome maps to a region orthologous to HSA14q. Mamm Genome — PubMed:PMID14722725 | DOI:10.1007/s00335-003-2280-1 — OMIA Phene_Article / Article\n- 1991. Role of the pancreas in the absorption and malabsorption of cobalamin (vitamin B-12) in dogs. J Nutr — PubMed:PMID1941244 — OMIA Phene_Article / Article\n- 2004. The functional cobalamin (vitamin B12)-intrinsic factor receptor is a novel complex of cubilin and amnionless. Blood — PubMed:PMID14576052 | DOI:10.1182/blood-2003-08-2852 — OMIA Phene_Article / Article\n- 2005. Amnionless function is required for cubilin brush-border expression and intrinsic factor-cobalamin (vitamin B12) absorption in vivo. Blood — PubMed:PMID15845892 | DOI:10.1182/blood-2005-03-1197 — OMIA Phene_Article / Article\n- 2015. Failure to thrive and life-threatening complications due to inherited selective cobalamin malabsorption effectively managed in a juvenile Australian shepherd dog. Can Vet J — PubMed:PMID26483576 — OMIA Phene_Article / Article\n- 2020. Review of cobalamin status and disorders of cobalamin metabolism in dogs. J Vet Intern Med — PubMed:PMID31758868 | DOI:10.1111/jvim.15638 — OMIA Phene_Article / Article\n\n## Comparative medicine (human OMIM)\nDerived from OMIA database dump (omia.xml, local); structured field, not verbatim prose. First-hand values below are verbatim substrings of the topic's pdf-raw/omia/<phene_id>.txt source file.\n- OMIM:618882 (type: trait) — OMIA Group_OMIM (via OMIA_ID)\n- OMIM:605799 (type: gene) — OMIA Group_OMIM (via OMIA_ID)\nverification_derived:\n  method: derived_from_dataset\n  source: \"OMIA database dump (omia.xml, local); fields Gene/Variant/Article/OMIM\"\n  note: \"Structured fields (gene, variant rsID/protein change, PubMed/DOI references, OMIM cross-link) extracted from OMIA dump and presented with first-hand values; not verbatim prose.\"\n","sources":["companion-breed-health — Komondor — Intestinal cobalamin malabsorption, AMN-related (hereditary; OMIA-verified breed predisposition)"],"source":{"authority":"companion-breed-health","title":"Komondor — Intestinal cobalamin malabsorption, AMN-related (hereditary; OMIA-verified breed predisposition)","url":"https://pubmed.ncbi.nlm.nih.gov/1848001/","retrieved":"","ref":"PMID 1848001","doc_type":"official source","source_document":"","verification_file":""},"source_document":"","source_file":"","trust":{"authority_tier":"ungraded","fidelity":"verbatim","license":null,"display_grade":"pending"},"tokens_estimated":1480,"generated_at":null,"tip":"Use /api/v1/topics to discover more topics. /api/v1/nutrient for precise single-point queries. /api/v1/cross_compare for 2-3 standard comparisons."}