Furthermore, we found 13 BXD lines with low expression signals for Krt4, Krt13 and Krtdap. Krt4 and Krt13 have been shown to be responsible for White sponge nevus (WSN), also known as Cannon's disease, which is an autosomal dominant skin condition in humans [45-47]. The gene discussed is KRT4; the disease is White sponge nevus.