Mendelian trait/disorder: yes

Mode of inheritance: Autosomal Recessive Lethal

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2013

Species-specific name: Haplotype JH1

Species-specific symbol: JH1

Mapping: Using genotype data from tens of thousands of North American Holsteins, Jerseys and Brown Swiss cattle each genotyped with approximately 50K SNPs on the BovineSNP50 BeadChip, VanRaden et al. (2011) identified five new recessive lethal haplotypes by searching for common haplotypes that are never homozygous in live animals. One of these haplotypes occurs in Jerseys only, and (following a convention proposed by breed-association staff) VanRaden et al. (2011) named it JH1, where J stands for Jersey and H for haplotype. It maps to chromosome BTA15, at 13-18Mb (UMD 3.0 genome assembly).

Molecular basis: Sonstegard et al (2013) investigated the lethal Jersey haplotype, namely haplotype JH1 on chromosome BTA15 (see Mapping section). They first refined the haplotype "to a 15-marker window (15,162,470 to 15,949,175)" and then obtained whole-genome sequence from 11 bulls carrying this haplotype. Analysis of the sequence of these carriers in the candidate region revealed a "high-impact stop-gain SNP located at position 15,707,169 on BTA15. This C-to-T transition SNP results in an Arginine to a stop codon in exon 3 of CWC15, the bovine protein CWC15 homolog of a spliceosome-associated protein . . . . This nonsense mutation would reduce the size of the CWC15 protein product from 231 amino acids in length to only 54 amino acids. A NCBI conserved domains search on the bovine CWC15 protein product reveals that this truncated protein would not have the conserved Cwf_Cwc_15 (pfam04889) domain present in the wildtype."

Breed: Jersey.

Associated gene: