Short tail, kinked (Japanese Bobtail)

Gene: HES7

Transmission: Autosomal dominant

The animal only has to have one copy of the mutation to be at risk of developing hypertrophic cardiomyopathy.  Animals with two copies of the mutation generally have more severe symptoms and an earlier onset of the disease than animals with just one copy of the mutation.  Offspring are potentially at risk of developing the disease if at least one parent carries the mutation.

Mutation: Substitution, HES7 gene: c.5A>G, p.(Val2Ala), exon1, chr.E1.

Medical system: Skeletal

Breeds: Asian domestic, Japanese Bobtail, Japanese Domestic

Age of onset of symptoms: Evident at birth.

A short tail, kinked phenotype has long been described in south Asian cats, including Malaysian domestic, Chinese domestic and Japanese domestic cats. The phenotype involves a reduced number of vertebrae to give the short tail, and hemivertebrae (scoliosis) to give the tail kink. The phenotype shows dominant heredity with complete penetrance, but somewhat variable expression, with minor, medium or extreme tail kinks described.  There short tail, kinked phenotype has no observed effect on reproduction, morbidity or mortality of the affected cat.  DNA studies identified a mutation within the HES7 gene as being responsible for the phenotype.  The HES7 gene is a DNA binding transcription factor expressed in the presomatic mesoderm of the developing embryo that is involved in the formation of somites and thus in the development of vertebrae.   Unlike the mutation in the TBXT gene, the major cause of short tail phenotype seen in European cats such as the Manx, homozygous mutations of the HES7 gene are not deleterious.

A sub-population of south Asian cats with short tails are negative for the known mutations within both the HES7 and the TBXT genes.  This suggests that additional yet to be described genetic mutations can also cause the short tail phenotype in cats.

See also: Short tail (bobtail, brachyury) (TBXT gene)

References:

OMIA link: [1987/9685]

Korzh V. (2023) Never-ending story of Brachyury: From short-tailed mice to tailless primates. Cells Dev 178:203896.  [pubmed/38072067]

Anderson H, Davison S, Lytle KM, et al. (2022) Genetic epidemiology of blood type, disease and trait variants, and genome-wide genetic diversity in over 11,000 domestic cats.  PLoS Genet. 16;18(6):e1009804.  [pubmed/35709088]

Lyons LA, Creighton EK, Alhaddad H et al. (2016) Whole genome sequencing in cats, identifies new models for blindness in AIPL1 and somite segmentation in HES7. BMC Genomics. 17:265.  [pubmed/27030474]

Xu X, Sun X, Hu XS, Zhuang Y et al. (2016) Whole Genome Sequencing Identifies a Missense Mutation in HES7 Associated with Short Tails in Asian Domestic Cats. Sci Rep. 6:31583. [pubmed/27560986]