Both SERCA2a and SERCA2b are present in epidermis, although the latter may predominate.[8] The absence of coexpressed SERCA3 in epidermis may explain the localization of Darier's disease to the skin.[8] While the SERCA defect is implicated in the pathogenesis of acrokeratosis verruciformis, the specific mutation is likely to be different, which probably explains the absence of dyskeratosis in acrokeratosis verruciformis of Hopf. The gene discussed is ATP2A3; the disease is acrokeratosis verruciformis.