Editing Turkish Van (section)

==Genetics==
The Turkish Van is largely free of genetic issues and breed-specific health defects. Unlike the Turkish Angora, the Turkish Van does not have issues with deafness.<ref name=":0" />

Additionally, due to the Turkish Van's larger size, spay or neutering procedures are sometimes delayed to around 1 year of age, as an early adjustment to their hormone levels can affect how their bones and muscles grow.<ref name=":0" />

The piebald spotting gene (partial [[leucism]]) appears in other different species (like the [[horse]] and the [[ball python]]). It also shows up in other breeds of cat, since the Van pattern is merely an extreme expression of the gene.<ref name="Robinson">{{Citation |last1=Vella |first1=Carolyn |last2=Shelton |first2= Lorraine |last3=McGonagle |first3=John |last4=Stanglein |first4=Terry |title=Robinson's Genetics for Cat Breeders and Veterinarians |place=Oxford |publisher=Butterworth Heineman |date=1999 |edition=4th |page=253 |isbn=0-7506-4069-3}}</ref>{{rp|148}}

The breed's variability of eye colour is genetically caused by the white spotting factor, which is a characteristic of this breed. The white spotting factor is the variable expression of the piebald gene that varies from the minimal degree (1), as in the blue-eyed cats with white tip on the tail to the maximal degree (8–9) that results in a Van-patterned cat, when coloured marks occupy at most 20% of the white background, but the white background in the breed covers about 80% of the body. Breeding two cats together with the same level of white spotting will produce cats with a similar degree of spotting.<ref name="Robinson" />{{rp|148}}

Van-patterned Turkish Vans are not prone to deafness, because their [[phenotype]] is associated with the Van pattern (S<sup>v</sup>) semi-dominant gene. Solid-white Turkish Angoras carry the [[Epistasis|epistatic]] (masking) white colour (W) dominant gene associated with white fur, blue eyes, and often deafness. All-white cats of Turkish Van stock may share this gene. All three types of cat may exhibit eye colours that are amber, blue or odd. Deafness is principally [[Congenital sensorineural deafness in cats|associated with white cats]] having two blue eyes.<ref name="Robinson" />{{rp|191}}