Other names: Scottish Fold osteochondrodysplasia (SFOCD), osteodystrophy  
Affected gene: TRPV4  
Inheritance: Incomplete autosomal dominant  
Mutation: Felis_catus_9.0 D3 g.18884219C>A c.1024G>T  
OMIA link: 000319-9685  

Breeds appropriate for testing:  Scottish Fold, Highland Fold  

Symptoms:  
Scottish Fold cats are characterized by their folded ears due to a mutation in the TRPV4 gene with autosomal dominant inheritance. Kittens are born with straight ears, which begin to fold forward at around three to four weeks of age. This mutation can cause osteochondrodysplasia, characterized by malformations of the distal forelimbs, distal hindlimbs, and tail. It is recommended to breed folded-ear cats only with normal-ear cats to avoid producing homozygous mutant cats. The age of onset, severity, and progression of osteochondrodysplasia are highly variable in affected heterozygous cats. It remains to be determined whether other genetic or environmental factors contribute to the observed phenotypic differences.

References:  
- Rorden, C., Griswold, M.C., Moses, N. et al. (2021). Radiographical survey of osteochondrodysplasia in Scottish Fold cats caused by the TRPV4 gene variant. Hum Genet 140(11):1525-1534. [PubMed: 34406467]  
- Takanosu, M., Hattori, Y. (2020). Osteochondrodysplasia in Scottish Fold cross-breed cats. J Vet Med Sci. 82(12):1769-1772. [PubMed: 33162427]  
- Gandolfi, B., Alamri, S., Darby, W.G. et al. (2016). A dominant TRPV4 variant underlies osteochondrodysplasia in Scottish Fold cats. Osteoarthritis and Cartilage 24:1441-1450. [PubMed: 27063440]  
- Takanosu, M., Takanosu, T., Suzuki, H., Suzuki, K. (2008). Incomplete dominant osteochondrodysplasia in heterozygous Scottish Fold cats. J Small Anim Pract. 49(4):197-9. [PubMed: 18339089]  
- Malik, R., Allan, G.S., Howlett, C.R., Thompson, D.E. et al. (1999). Osteochondrodysplasia in Scottish Fold cats. Australian Veterinary Journal 77:85-92. [PubMed: 10078353]