--- license: permission_granted topic_id: companion_breed_health_lhasa_apso_progressive_retinal_atrophy_4_dog category: companion-breed-health title: "Lhasa Apso — Progressive retinal atrophy 4 (hereditary; OMIA-verified breed predisposition)" lang: en source: "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." source_file: pdf-raw/breed-health/lhasa_apso_progressive_retinal_atrophy_4_4409.txt date_parsed: 2026-08-02 tokens_estimated: 422 verification: method: substring_match claims: 7 passed: 7 date: 2026-08-02 recovered: false path: companion-breed-health/companion_breed_health_lhasa_apso_progressive_retinal_atrophy_4_dog/01_companion_breed_health_lhasa_apso_progressive_retinal_atrophy_4_dog.md source_document: "OMIA — Online Mendelian Inheritance in Animals (University of Sydney)" citation: authority: "OMIA — Online Mendelian Inheritance in Animals (University of Sydney)" title: "Lhasa Apso — Progressive retinal atrophy 4 (hereditary; OMIA-verified breed predisposition)" url: "https://omia.org/OMIA002289/9615/" retrieved: "2026-08-02" ref: "OMIA breed-specific hereditary-disorder records (omia.org), derived from local OMIA database dump; dataset: https://doi.org/10.25910/2AMR-PV70" doc_type: "academic animal-genetics database (breed-specific disorder entries)" needs_review: false
Lhasa Apso — Progressive retinal atrophy 4 (hereditary; OMIA-verified breed predisposition)
Source: 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.
Claims
Breed: Lhasa Apso (Dog)Disorder: Progressive retinal atrophy 4Mode of inheritance: Autosomal recessiveSummary: Many different forms of progressive retinal atrophy (PRA) exist and more than 10 different genes have been identified so far in dogs to have likely causal variants for PRA. Please review OMIA for other variants. This OMIA entry will focus on PRA due the variants in the IMPG2 gene.Clin feat: Clinical signs are consistent with a rod-cone degeneration in both eyes. Initially, there may be mild attenuation of retinal blood vessels, hyper-reflectivity of the tapetum, optic disc discolouration and night blindness. As the disease progresses, the blindness becomes moderate to severe with attenuation of retinal blood vessel; hyper-reflectivity of the tapetum, due to retinal thinning; and optic disc atrophy (Hitti-Malin et al., 2020). Of the 19 out of 21 dogs for whom an age at diagnosis is known, approximately 50% were diagnosed between the age of 5 and 8 years (Hitti-Malin et al., 2020). [IT thanks DVM student Andrew Barker, who provided the basis of this contribution in April 2022].Defect: yesPrevalence: Hitti-Malin et al. (2020): validation of this variant [the LINE-1 variant] in 447 dogs of 123 breeds determined it was private to LA dogs. . . . The recently estimated mutant allele frequency of 0.1, generated from the 911 DNA tested LA during 2 years of use of a DNA test based on this work, indicates that 1 in 100 dogs are likely to be affected with this form of PRA, and an 18% carrier frequency within the LA population.
Associated gene(s)
Derived 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.
- Gene: Entrez Gene ID 388303885 (no symbol in OMIA GeneSynonym) — OMIA Phene_Gene
- OMIA molecular-genetics note: Hitti-Malin et al. (2020): "whole-genome sequencing analysis that revealed a long interspersed element-1 (LINE-1) insertion upstream of the IMPG2 gene."
Evidence (references)
Derived 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.
- 2012. Genetic and phenotypic variations of inherited retinal diseases in dogs: the power of within- and across-breed studies. Mamm Genome — PubMed:PMID22065099 | DOI:10.1007/s00335-011-9361-3 — OMIA Phene_Article / Article
- 2020. A LINE-1 insertion situated in the promoter of IMPG2 is associated with autosomal recessive progressive retinal atrophy in Lhasa Apso dogs. BMC Genet — PubMed:PMID32894063 | DOI:10.1186/s12863-020-00911-w — OMIA Phene_Article / Article
- 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
- 2024. Consensus guidelines for nomenclature of companion animal inherited retinal disorders. Vet Ophthalmol — PubMed:PMID38334230 | DOI:10.1111/vop.13185 — OMIA Phene_Article / Article
Comparative medicine (human OMIM)
Derived 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.
- OMIM:613581 (type: trait) — OMIA Group_OMIM (via OMIA_ID)
- OMIM:616152 (type: trait) — OMIA Group_OMIM (via OMIA_ID)
- OMIM:607056 (type: gene) — OMIA Group_OMIM (via OMIA_ID)
verification_derived: method: derived_from_dataset source: "OMIA database dump (omia.xml, local); fields Gene/Variant/Article/OMIM" 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."