This mutation is like melanism or albinism, but instead of too much pigment or not enough pigment, is has an abundance of red pigment.

Erythrism in a Black-backed Jackal - https://i.pinimg.com/originals/80/16/cf/8016cf06c8af75e4405c08a917aec2a6.jpg
Erythism in a badger - http://www.uksafari.com/jpeg2/badgr010.jpg

This mutation could cause any markings that are currently on it to change to a reddish version, if that is possible. The shade of the markings would depend on which color they were before, so a light color would be light red, and a dark color would be dark red.