Tennessee Walking Horse (Horse) — Night blindness, congenital stationary, GRM6-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: Tennessee Walking Horse (Horse)
Disorder:
Summary: Hack et al. (2021) reported a Tennessee Walking Horse with congenital stationary night blindness (CSNB) that did not have a the TRPM1 variant known to cause CSNB in horses (see OMIA:001341-9796 : Night blindness, congenital stationary, TRPM1-related in Equus caballus). Esdaile et al. (2024) provides additional evidence that GRM6 c.533Cgt;T homozygosity is likely causal to CSNB in Tennessee Walking Horses, Standardbreds, and Missouri Fox Trotting Horses.
Defect: yes
Prevalence: Hack et al. (2021): This variant [GRM6 c.533Cgt;T] was not detected in 273 horses from three additional breeds. The estimated allele frequency in Tennessee Walking Horses is 10%. Esdaile et al. (2024): The CSNB2 allele was present in nine breeds [American Quarter Horse, Racking Horse, Rocky Mountain Horse, American Saddlebred, Spotted Saddle Horse, Standardbred (pacer), Miniature Horse, Missouri Fox Trotting Horse, Morgan], ranging in frequency from 0.0010 in American Quarter Horses (n = 486) to 0.17 in pacing Standardbreds (n = 110 ...). The CSNB2 allele was not detected in trotting Standardbreds (n = 70), Thoroughbreds (n = 1787), Hackney Horses (n = 47), Hackney Ponies (n = 44), and Shetland Ponies (n = 99 ...).

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 388955788 (no symbol in OMIA GeneSynonym) — OMIA Phene_Gene
OMIA molecular-genetics note: Hack et al. (2021): "WGS [whole genome sequencing] analysis identified a missense mutation in metabotropic glutamate receptor 6 (GRM6) (c.533C>T p.Thr178Met)."

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.

2021. Whole-genome sequencing identifies missense mutation in GRM6 as the likely cause of congenital stationary night blindness in a Tennessee Walking Horse. Equine Vet J — PubMed:PMID32654228 | DOI:10.1111/evj.13318 — OMIA Phene_Article / Article
2024. Additional evidence supports GRM6 p.Thr178Met as a cause of congenital stationary night blindness in three horse breeds. Vet Ophthalmol — PubMed:PMID37815029 | DOI:10.1111/vop.13151 — 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:604096 (type: gene) — OMIA Group_OMIM (via OMIA_ID)
OMIM:257270 (type: trait) — OMIA Group_OMIM (via OMIA_ID)

Tennessee Walking Horse (Horse) — Night blindness, congenital stationary, GRM6-related (hereditary; OMIA-verified breed predisposition)