White Sponge Nevus (WSN) is a rare mucosal leukokeratosis, occurring in less than 1 in 200,000 births, that can be transmitted in a dominant fashion in association with pathogenic variants of the KRT4 and KRT13 genes encoding keratin 4 and 13 [1,2,3]. The gene discussed is KRT4; the disease is White sponge nevus.