Dominant White and White Spotting are controlled by the KIT-gene. Dominant white is also described as the W-locus and White Spotting as the S-locus. The gene/genes controlling the pattern of White Spotting is still unknown. Additionally, not all white spots or patterns result from the KIT-gene as other genes can also have mutations that result in depigmentation phenotypes.
The KIT-gene has three variants (alleles). The DW allele is dominant over the alleles Ws and N; allele Ws is dominant over allele N. The dominant allele DW results in a white coat colour. The allele Ws in white spotting and the allele N has no effect on the coat colour.
Dominant White is distinct from albinism (C-locus) which results from a mutation in theTYR (tyrosinase) gene that has no known impact on hearing. One or two copies of the DW allele will result in a white cat with varying degrees of hearing impairment.
The Dominant White & White Spotting test encloses the following results:
| Dominant White & White Spotting (W- en S-locus) | Coat Colour |
|---|---|
| N/N | Not white and no white spotting |
| N/DW | White |
| DW/DW | White |
| N/Ws | Cat has white spotting |
| DW/Ws | White |
| Ws/Ws | Cat has white spotting |