Keratosis follicularis

Overview
Keratosis follicularis (Darier-White disease) is a genetic disorder of abnormal keratinization and is inherited in an autosomal dominant pattern.

Keratosis follicularis is characterized clinically by scaly, warty, crusted papules distributed mostly on the seborrheic areas of the body. Nail involvement is characterized by V-shaped nicking at the distal aspect of the nail bed, longitudinal red and white alternating bands, and subungual hyperkeratosis (buildup of scales underneath the nailplate). Mucosal membrane involvement may occur as white papules on the buccal mucosae, palate, and gingiva with a cobblestone appearance.

Physical examination classically shows keratotic papules that are distributed mostly on the so-called "seborrheic" areas of the body.

Nail involvement is not uncommon and is characterized by V-shaped nicking at the distal aspect of the nail bed, longitudinal red and white alternating bands, and subungual hyperkeratosis.

The mutation has been traced to chromosome 12, where a spectrum of mutations within the ATP2A2 gene encode the calcium ATPase of the sarco/endoplasmic reticulum (SERCA2).