Mutations in the secreted leukocyte antigen-6 (Ly6)/urokinase-type plasminogen activator (uPAR)-related protein gene, also known as SLURP1, cause Mal de Meleda. Mal de Meleda is a rare autosomal recessive disorder characterized by diffuse transgressive palmoplantar keratoderma, keratotic skin lesions, perioral erythema, brachydactyly, and nail abnormalities.