Darier disease (keratosis follicularis) is an autosomal dominant genodermatosis with characteristic greasy crusted papules in seborrhoeic distribution. Its molecular defect is in:

• A ATP2A2 gene encoding SERCA2 (sarco/endoplasmic reticulum Ca²⁺-ATPase pump type 2) ✓
• B Filaggrin (chromosome 1q21)
• C Connexin-26 (GJB2)
• D Transglutaminase-1 (TGM1)

Explanation

Darier disease is caused by loss-of-function mutations in ATP2A2, encoding SERCA2 (the sarco/endoplasmic reticulum Ca²⁺-ATPase type 2). SERCA2 dysfunction impairs calcium homeostasis in the endoplasmic reticulum, disrupting desmosome assembly and cell-cell adhesion, leading to suprabasal acantholysis—the hallmark histological feature ('corps ronds' and 'grains'). Darier disease is exacerbated by heat, sweating, UV exposure, and bacterial/viral superinfection. Oral retinoids (acitretin) are the treatment of choice for moderate-to-severe disease.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.