Phenotypes

Drögemüller et al. (2011) identified a likely causal variant in Tyrolean Grey cattle as the synonymous c.2229C>T SNP, which "is located within a putative exonic splice enhancer (ESE) and the variant allele leads to partial retention of the entire intron 19 and a premature stop codon in the aberrant MFN2 transcript. Thus we have identified a highly unusual splicing defect, where an exonic single base exchange leads to the retention of the pr...

In a segregation analysis of data from a breeding herd, Dolf et al. (1998) provided convincing evidence of autosomal recessive inheritance.

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.

Exome sequencing by Sasaki et al. (2016) within the candidate region (see Mapping section) revealed a likely causal missense variant: g.62382825G > A, p.Pro372Leu) in exon 10 of solute carrier family 12, member 1 (SLC12A1).

O’Callaghan et al. (2023) "present a detailed phenotypic and molecular characterization of an intronic variant in cattle that activates cryptic splicing of the adenylate kinase 9 (AK9) gene resulting in extreme subfertility associated with impaired sperm hyperactivation, failure of oocyte binding/penetration, and low frequency of embryo development culminating in severely compromised field fertility."

In what must be a sign of the times, Karageorgos et al. (2007) documented the first reported occurrence of this disorder in cattle and, in the same paper, also reported its molecular basis; in this case a missense mutation E452K (c.1354G>A) in the gene for alpha-N-acetylglucosaminidase (NAGLU).

Häfliger et al. (2020; PMID 32069517): "Whole‐genome sequencing of one case, variant filtering against controls and genotyping of a larger cohort of Cika cattle led to the detection of a likely pathogenic protein‐changing variant perfectly associated with the disease: a missense variant on chromosome 6 in ADAMTS3 (NM_001192797.1: c.1222C>T), which affects an evolutionary conserved residue (NP_001179726.1: p.(His408Tyr))"