I believe it is not just bald faces but a certain pattern of bald face that you see deafness in. If it was a simple as a simple gene then you would see more solid colored Gunners deaf and you do not. The ones that are all have the same face markings as he dose. Normally very close if not hitting the ear. While it is most likely not just the color but more where it is located on the face it makes it more complicated then a simple gene.
This has piqued my curiosity to see if certain sire/dam lines carry the "bald face/deaf" gene markers, or if it is a mutation through embryonic development.