What causes Leukonychia totalis ?
What causes leukonychia totalis? Leukonychia totalis (also called total leukonychia) is thought to be due to abnormal keratinization (conversion into keratin) of the nail plate. Keratin is a protein that is a major component of the epidermis (outer layer of skin), hair, nails, and horny tissues. The condition is usually inherited, following either an autosomal dominant or autosomal recessive inheritance pattern. These inherited forms can be caused by mutations in the PLCD1 gene. In some cases, leukonychia occurs in association with other underlying abnormalities or syndromes. Conditions that have been reported include palmoplantar keratoderma; certain types of cysts; severe keratosis pilaris; pili torti; hypotrichosis (lack of hair growth); onychorrhexis (brittle nails); koilonychia (spoon-shaped nails); Bart-Pumphrey syndrome; and Buschkell-Gorlin syndrome, when it occurs with sebaceous cysts and kidney stones. It has also reportedly been associated with typhoid fever, leprosy, cirrhosis, nail biting, trichinosis, and cytotoxic drugs (drugs that are toxic to cells). In a few cases, the cause of leukonychia is unknown (idiopathic).