--- license: permission_granted topic_id: companion_breed_health_friesian_horse_omia3960_horse category: companion-breed-health title: "Friesian (Horse) — Dwarfism, B4GALT7-related (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 2026-08-23 from local OMIA database dump." source_file: pdf-raw/breed-health/friesian_horse_omia3960_3960.txt date_parsed: 2026-08-23 tokens_estimated: 329 verification: method: substring_match claims: 6 passed: 6 date: 2026-08-23 recovered: false path: companion-breed-health/companion_breed_health_friesian_horse_omia3960_horse/01_companion_breed_health_friesian_horse_omia3960_horse.md source_document: "OMIA — Online Mendelian Inheritance in Animals (University of Sydney)" citation: authority: "OMIA — Online Mendelian Inheritance in Animals (University of Sydney)" title: "Friesian (Horse) — Dwarfism, B4GALT7-related (hereditary; OMIA-verified breed predisposition)" url: "https://omia.org/OMIA002068/9796/" retrieved: "2026-08-23" 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
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."---
Friesian (Horse) — Dwarfism, B4GALT7-related (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: Friesian (Horse)Disorder:Mode of inheritance: Autosomal recessiveClin feat: As summarised by Orr et al. (2010), the Friesian dwarf phenotype results from physeal growth retardation in both limbs and ribs, reflected in a characteristic disproportional growth disturbance. The potential for post-natal growth in these animals, albeit at a reduced rate, is responsible for mature dwarfs having a head of the same size as unaffected animals, a broader chest with narrowing at the costochondral junction, a disproportionally long back and abnormally short limbs. Furthermore, radiographs reveal a dysplastic metaphysis of the distal metacarpus and metatarsus. Light microscopy of growth plates at the costochondral junction demonstrates an irregular transition from cartilage to bone, and thickening and disturbed formation of chondrocyte columns, which is similar to findings in osteochondrodysplasia.Defect: yesPrevalence: 177 Friesian horses were tested, with discovery of 22 carriers and 155 homozygotes for the reference allele. Not tested in other breeds. (Leegwater et al., 2016). (FN thanks Elizabeth Huffman, who substantially enhanced this section, working under the supervision of Professor Ernie Bailey; 23 April 2020)
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 388948310 (no symbol in OMIA GeneSynonym) — OMIA Phene_Gene
- OMIA molecular-genetics note: Whole genome sequencing was conducted on 4 dwarf Friesians and 3 non-affected Friesian controls, and the resultant sequences were compared in the candidate region with sequence from the horse reference genome and a Quarter Horse (a breed in which dwarfism has not been reported) (Leegwater et al., 2016). The authors identified a likely causal (missense) variant in Friesians as g.4535550C>T; c.50G>A…
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.
- 2008. Phenotypic diagnosis of dwarfism in six Friesian horses. Equine Vet J — PubMed:PMID18267883 | DOI:10.2746/042516408X278201 — OMIA Phene_Article / Article
- 2010. Genome-wide SNP association-based localization of a dwarfism gene in Friesian dwarf horses. Anim Genet — PubMed:PMID21070269 | DOI:10.1111/j.1365-2052.2010.02091.x — OMIA Phene_Article / Article
- 2009. Normal function of the hypothalamic-pituitary growth axis in three dwarf Friesian foals. Vet Rec — PubMed:PMID19783851 | DOI:10.1136/vr.165.13.373 — OMIA Phene_Article / Article
- 2000. Het Fokken van het Friese Paard [Breeding of the Friesian horse]. Schaafsma & Brouwer, Dokkum — OMIA Phene_Article / Article
- 2016. Dwarfism with joint laxity in Friesian horses is associated with a splice site mutation in B4GALT7. BMC Genomics — PubMed:PMID27793082 | DOI:10.1186/s12864-016-3186-0 — OMIA Phene_Article / Article
- 2021. Animal models of Ehlers-Danlos syndromes: Phenotype, pathogenesis, and translational potential. Front Genet — PubMed:PMID34712265 | DOI:10.3389/fgene.2021.726474 — OMIA Phene_Article / Article
- 2024. Predicted genetic burden and frequency of phenotype-associated variants in the horse. Sci Rep — PubMed:PMID38600096 | DOI:10.1038/s41598-024-57872-8 — OMIA Phene_Article / Article
- 2026. Pedigree-based assessment of genetic structure and disease-associated variants in Friesian horses in Brazil. J Equine Vet Sci — PubMed:PMID41865906 | DOI:10.1016/j.jevs.2026.105860 — OMIA Phene_Article / Article
- 2026. Deficiency in homozygous haplotypes reveals recessive lethal variants affecting fertility and viability in the Friesian horse. BMC Genomics — PubMed:PMID41808016 | DOI:10.1186/s12864-026-12728-5 — 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:130070 (type: trait) — OMIA Group_OMIM (via OMIA_ID)
- OMIM:604327 (type: gene) — OMIA Group_OMIM (via OMIA_ID)