White cats, white spotting and deafness

New information on how white and white spotting works

In October 2014 a research paper on the genes for white cats and dominant piebald spotting was published. Now UC Davis (VGL) has developed a DNA-test for this locus.

What is new?

The genes for dominant white W (self-coloured white) and dominant white spotting ws (previously S) are found on the same locus, as different alleles – variations of the gene. Risk factors for white cats being deaf or hearing is dependent of which genes they carry:

  • Homozygous white cats WW are likely to be fully or partially deaf
  • White carrying white spotting Wws have a higher risk of being deaf than White carrying non-white Ww
  • White cats carrying non-white have a higher chance of hearing

The number of tested and controlled cats is not large (270 cats from 30 cat breeds), but the study indicates that

  • white cats should never be bred to other white cats (this is a rule in FIFe already)
  • white cats should not be bred to white spotted cats, only non-white to lower risk of deaf offspring

The different possibilities for this gene: Genotype Colour – Farge WW White cat – helhvit Wws White cat, carrier of white spotting – helhvit og bærer av hvitflekk Ww White cat, not carrier of white spotting – helhvit og ikke bærer av hvitflekk wsws White spotting (highwhite) – hvitflekk: van, harlekin eller bicolor wsw White spotting (bicolour or white paws/bib) – hvitflekk: bicolour eller hvitepoter+bryst/mage ww Not white or white spotting – ikke helhvit, ikke hvitflekk


The locus can be tested at VGL, UC Davis for $50: Read more. The test is now (2018) also offered by Laboklin/Labogen, and included in the test panel at MyCatDNA. Risk of deafness for …

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