{"topic_id":"companion_breed_health_shih_tzu_omia4642_dog","category":"companion-breed-health","context":"---\nlicense: permission_granted\ntopic_id: companion_breed_health_shih_tzu_omia4642_dog\ncategory: companion-breed-health\ntitle: \"Shih Tzu — Vitreous degeneration (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/shih_tzu_omia4642_4642.txt\ndate_parsed: 2026-08-02\ntokens_estimated: 262\nverification:\n  method: substring_match\n  claims: 4\n  passed: 4\n  date: 2026-08-02\nrecovered: false\npath: companion-breed-health/companion_breed_health_shih_tzu_omia4642_dog/01_companion_breed_health_shih_tzu_omia4642_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: \"Shih Tzu — Vitreous degeneration (hereditary; OMIA-verified breed predisposition)\"\n  url: \"https://omia.org/OMIA002409/9615/\"\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# Shih Tzu — Vitreous degeneration (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: Shih Tzu (Dog)`\n- `Disorder: `\n- `Summary: Krishnan et al. (2019) reported a retrospective study of 4217 dogs from the Companion Animal Eye Registry (CAER) that underwent breed screening ophthalmic examinations between 2013 and 2016. The breeds analyzed included the Italian Greyhound, Shih Tzu, Affenpinscher, Bichon Frise, Brussels Griffon, Whippets, and Greyhound. Data collected from CAER included age, gender, number of examinations, and whether vitreous degeneration, along with cataracts, lens luxation, glaucoma and/or retinal detachment were present in either or both eyes. ... The study found that breed and age are significant drivers for developing VD. Italian Greyhounds, Brussels Griffons, and Shih Tzus have a significantly higher likelihood of VD compared to the negative control breed, the Greyhound. ... However, no association was identified between vitreous degeneration and cataracts, lens luxation, glaucoma, or retinal detachment.`\n- `Defect: yes`\n## Evidence (references)\nDerived from OMIA database dump (omia.xml, local); structured field, not verbatim prose.\n- 2020. Vitreous degeneration and associated ocular abnormalities in the dog.. Vet Ophthalmol — PubMed:PMID31464365 | DOI:10.1111/vop.12707 — OMIA Phene_Article / Article\n- 2023. Long-term evaluation of the effects of vitreous degeneration on cataracts and retinal detachment in dogs.. Vet Ophthalmol — PubMed:PMID36840613 | DOI:10.1111/vop.13078 — OMIA Phene_Article / Article\n- 2021. The Blue Book: Ocular disorders presumed to be inherited in purebred dogs. 13th Edition. https://ofa.org/wp-content/uploads/2022/10/ACVO-Blue-Book-2021.pdf — OMIA Phene_Article / Article\n## Evidence (references)\nDerived from OMIA database dump (omia.xml, local); structured field, not verbatim prose.\n- 2020. Vitreous degeneration and associated ocular abnormalities in the dog. Vet Ophthalmol — PubMed:PMID31464365 | DOI:10.1111/vop.12707 — OMIA Phene_Article / Article\n- 2023. Long-term evaluation of the effects of vitreous degeneration on cataracts and retinal detachment in dogs. Vet Ophthalmol — PubMed:PMID36840613 | DOI:10.1111/vop.13078 — OMIA Phene_Article / Article\n- 2021. The Blue Book: Ocular disorders presumed to be inherited in purebred dogs. 13th Edition. https://ofa.org/wp-content/uploads/2022/10/ACVO-Blue-Book-2021.pdf — OMIA Phene_Article / Article\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- 2020. Vitreous degeneration and associated ocular abnormalities in the dog. Vet Ophthalmol — PubMed:PMID31464365 | DOI:10.1111/vop.12707 — OMIA Phene_Article / Article\n- 2023. Long-term evaluation of the effects of vitreous degeneration on cataracts and retinal detachment in dogs. Vet Ophthalmol — PubMed:PMID36840613 | DOI:10.1111/vop.13078 — OMIA Phene_Article / Article\n- 2021. The Blue Book: Ocular disorders presumed to be inherited in purebred dogs. 13th Edition. https://ofa.org/wp-content/uploads/2022/10/ACVO-Blue-Book-2021.pdf — OMIA Phene_Article / Article\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## 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- 2020. Vitreous degeneration and associated ocular abnormalities in the dog. Vet Ophthalmol — PubMed:PMID31464365 | DOI:10.1111/vop.12707 — OMIA Phene_Article / Article\n- 2023. Long-term evaluation of the effects of vitreous degeneration on cataracts and retinal detachment in dogs. Vet Ophthalmol — PubMed:PMID36840613 | DOI:10.1111/vop.13078 — OMIA Phene_Article / Article\n- 2021. The Blue Book: Ocular disorders presumed to be inherited in purebred dogs. 13th Edition. https://ofa.org/wp-content/uploads/2022/10/ACVO-Blue-Book-2021.pdf — OMIA Phene_Article / Article\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## 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- 2020. Vitreous degeneration and associated ocular abnormalities in the dog. Vet Ophthalmol — PubMed:PMID31464365 | DOI:10.1111/vop.12707 — OMIA Phene_Article / Article\n- 2023. Long-term evaluation of the effects of vitreous degeneration on cataracts and retinal detachment in dogs. Vet Ophthalmol — PubMed:PMID36840613 | DOI:10.1111/vop.13078 — OMIA Phene_Article / Article\n- 2021. The Blue Book: Ocular disorders presumed to be inherited in purebred dogs. 13th Edition. https://ofa.org/wp-content/uploads/2022/10/ACVO-Blue-Book-2021.pdf — OMIA Phene_Article / Article\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 — Shih Tzu — Vitreous degeneration (hereditary; OMIA-verified breed predisposition) (retrieved 2026-08-22)"],"source":{"authority":"companion-breed-health","title":"Shih Tzu — Vitreous degeneration (hereditary; OMIA-verified breed predisposition)","url":"https://pubmed.ncbi.nlm.nih.gov/31464365/","retrieved":"2026-08-22","ref":"PMID 31464365","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":649,"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."}