Monarch Disease Ontology entry MONDO_0015748 (hereditary mucosal leukokeratosis) can be described as follows. White sponge nevus (WSN) is a rare and autosomal dominant genetic disease in which the oral mucosa is white or grayish, thickened, folded, and spongy. The onset is early in life, and both sexes are affected equally. Other common sites include the tongue, floor of the mouth, and alveolar mucosa. Also known as: White sponge nevus of Cannon, white sponge nevus, white sponge nevus of Cannon.