In other species: dog

Categories: Vision / eye phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 262300 (trait) , 605080 (gene)

Links to relevant human diseases in MONDO:

• MONDO:0009875: achromatopsia 3

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal recessive

Disease-related: yes

Key variant known: yes

Year key variant first reported: 2021

Cross-species summary: This disorder has been initially renamed in OMIA on the basis of the review by Miyadera et al. (2012). In 2021, entries for Achromatopsia (cone degeneration, hemeralopia), AMAL (OMIA 001365-9615) and Achromatopsia (cone degeneration, hemeralopia), GSPT (OMIA 001676-9615) were merged and renamed 'Achromatopsia-3, CNGB3-related'.

Species-specific symbol: OH1

Species-specific description: Häfliger et al. (2021) "characterize the phenotype and the genetic aetiology of a recessive form of congenital day-blindness observed in several cases of purebred Original Braunvieh cattle. ... Achromatopsia is a monogenic Mendelian disease characterized by the loss of cone photoreceptor function resulting in day-blindness, total color-blindness, and decreased central visual acuity."

Inheritance: Häfliger et al. (2021) "available pedigree records of all 12 cases were analyzed and multiple inbreeding loops between the parents were found ... . We detected a single common ancestor occurring 8–11 generations ago. Due to the obvious history of inbreeding, a recessive inherited condition was considered.

Molecular basis: Häfliger et al. (2021): "After SNP genotyping and subsequent homozygosity mapping with twelve affected cattle, we performed whole-genome sequencing and variant calling of three cases. We identified a single missense variant in the bovine CNGB3 gene situated in a ~2.5 Mb homozygous genome region on chromosome 14 shared between all cases. All affected cattle were homozygous carriers of the p.Asp251Asn mutation that was predicted to be deleterious, affecting an evolutionary conserved residue."

Clinical features: Häfliger et al. (2021): "Electroretinography in an affected calf revealed absent cone-mediated function, whereas the rods continue to function normally. Brain areas involved in vision were morphologically normal."

Pathology: Häfliger et al. (2021): "When targeting cones by immunofluorescence, a decrease in cone number and an accumulation of beta subunits of cone cyclic-nucleotide gated channel (CNGB3) in the outer plexiform layer of affected animals was obvious."

Prevalence: Häfliger et al. (2021) estimated "an allele frequency of the deleterious allele of ~8%."

Breed: Original Schweizer Braunvieh, Switzerland (Cattle) (VBO_0003764).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).

Associated gene: