Phenotypes

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."

Having a good idea of the map location of the gene responsible for this disorder in Brown Swiss cattle, Drögemüller et al. (2010) used sequence capture followed by resequencing to identify a single base insertion in the gene for sulfite oxidase (SUOX) as being causative for this disorder in this breed. The synthesis of sulfite oxidase is dependent upon molybdenum cofactor (Moco), whose synthesis is dependent upon two peptides (MOCS1A and MOCS1...

Weber et al. (2026) investigated an inherited neuromuscular disorder in Brown Swiss cattle. Use of whole genome sequencing resulted in the identification of a "rare homozygous missense variant in LIPC (chr10:51715800G>C; NM_001035410.1:c.924C>G; p.Phe308Leu; omia.variant:1842) ... and in-silico predictions classified this variant as deleterious. Population-level genotyping of over 20.000 BS cattle revealed a variant allele frequency of 1...

Widmer et al. (2023): "A breed specific frameshift duplication in WNT10B (rs525007739; c.910dupC; p.Arg304ProfsTer14) ... was found to be associated with a 21.5-fold increased risk of brachygnathia inferior in homozygous [Brwon Swiss] carriers."

To date, all cases of this lethal disorder in cattle appear to be due to the same mutation, namely a nonsense mutation in the 5th of 9 exons of the ASS gene. Normal bovine ASS is a peptide containing 412 amino acids; the mutation occurs in the 86th codon.

Rothammer et al. (2017): "comparisons of the sequence of [the candidate] haplotype [see Genetic mapping section] with sequence data from four Braunvieh sires and the Aurochs genome identified two possible candidate causal mutations at positions 39,829,806 bp (G/A; R45Q) [omia.variant:847] and 39,864,148 bp (C/T; T444I) [omia.variant:848] that were absent in 1682 animals from various bovine breeds included in the 1000 bull genomes project. Both...

Fontanesi  et al. (2010): "[V]ariation in the white spotting in several cattle breeds is largely influenced by the multiple allelic series at the S locus, which includes at least four alleles (Olson 1999): SH (Hereford pattern), SP (Pinzgauer pattern or lineback), S+ (non-spotted) and s (spotting pattern). The SH allele gives white face, belly, feet and tail, often with a white stripe over the shoulder when homozygous. The SP allele gives pigm...

For information relating to Bos indicus cattle see: OMIA 001199-9915 : Coat colour, extension in Bos indicus

Awasthi Mishra et al. (2017) reported a likely causal variant for this classic phene: "The belt-associated variant was a copy number variant (CNV) involving the quadruplication of a 6 kb non-coding sequence located approximately 16 kb upstream of the TWIST2 gene. Increased copy numbers at this CNV were strongly associated with the belt phenotype in a cohort of 333 cases and 1322 controls. We hypothesized that the CNV causes aberrant expression...

See also: OMIA:001737-9913 : Coat colour, white spotting, KIT-related in Bos taurus (taurine cattle)

Fontanesi  et al. (2010): "[V]ariation in the white spotting in several cattle breeds is largely influenced by the multiple allelic series at the S locus, which includes at least four alleles (Olson 1999): SH (Hereford pattern), SP (Pinzgauer pattern or lineback), S+ (non-spotted) and s (spotting pattern). The SH allele gives white face, belly, feet and tail, often with a white stripe over the shoulder when homozygous. The SP allele gives pigm...

See also OMIA:002280-9913 : Coat colour, albinism, generic in Bos taurus (taurine cattle). Some refrences for albinism in cattle that have not been confirmed to be due to TYR variants have been moved to the generic entry [09/09/2025].

Burgstaller et al. (2016) have provided strong evidence that the FH2 frameshift mutation (see OMIA 001958-9913), namely c.771_778delTTGAAAAGinsCATC (rs379675307) in SLC2A2, is actually causative of Fanconi-Bickel syndrome in Fleckvieh cattle. Joller et al. (2018) reported the same likely causal variant in a Swiss Braunvieh calf.

Häfliger et al. (2021) investigated “the two Braunvieh populations reared in Switzerland, the dairy Brown Swiss (BS) and the dual-purpose Original Braunvieh (OB). We performed a genome-wide analysis of array data of trios (sire, dam, and offspring) from the routine genomic selection to identify candidate regions showing missing homozygosity and phenotypic associations with five fertility, ten birth, and nine growth-related traits. In addition,...

As reported by Schwarzenbacher et al. (2016),"Homozygous calves suffer from chronic airway disease resulting in poor growth performance and high juvenile mortality. The respiratory manifestations resemble key features of diseases resulting from impaired function of airway cilia." As pointed out carefully by Schwarzenbacher et al. (2016), not all homozygotes die, i.e. the lethal allele has incomplete penetrance.