The inheritance of the Whitehead trait is not totally understood and "mismarks" caused by this trait are not to standard in several breeds. For example the AKC Australian Shepherd standard reads "white on the head should not predominate, and the eyes must be fully surrounded by color and pigment." Breeders can often be surprised by excessively whiteheaded offspring from 2 parents who are to standard, as the following example demonstrates.

Breed - Australian Shepherd
Breed - Australian Shepherd

White around the area of the ears can be a cause for deafness as with Canon's example.

Unilaterally Deaf, Unilaterally Hearing Impaired
Unilaterally Deaf, Unilaterally Hearing Impaired

A better understanding of the inheritance of the trait and available genetic testing would be helpful to many breeders.

Prof. Yuri Tani Utsunomiya DVM, MSc, PhD and Rafaela Beatriz Pintor Torrecilha DVM, MSc, PhD, have kindly offered their expertise to search for the genetic marker/s for the Whitehead trait.

Their research uses the "Illumina CanineHD Array" which is the same array that Embark uses for their testing. Embark provides this "raw data", which includes over 200,000 individual markers, for every tested dog. This raw data requires a special program to open. The following are screen shots as to what the data looks like.

SNP array may help in locating a chromosomal segment containing the variant, but will not provide sufficient evidence to identify the precise mutation. Identifying the mutation will need to be achieved using whole genome sequences.
The first stage of this research will be to focus on mapping a candidate genomic loci first. 

Embark raw data can be found at the bottom of your dog's result page as these screen shots show. The link needed is the "Download Zip File"

The raw data ZIP file can be emailed to Mary Langevin -

The following video shows the typical spread of white over the body caused by Whitehead.
Video by Sandra Hansen