Calcium-transporting ATPase sarcoplasmic reticulum type (Ca++ ATPase) is a magnesium-dependent enzyme that catalyzes the hydrolysis of ATP coupled with the translocation of calcium from the cytosol to the sarcoplasmic reticulum lumen. Defects in ATP2A2 are a cause of acrokeratosis verruciformis (AKV), also known as Hopf disease. AKV is a localized disorder of keratinization, which is inherited as an autosomal dominant trait. Its onset is early in life with multiple flat-topped, flesh-colored papules on the hands and feet,Porcineunctate keratoses on the palms and soles, with varying degrees of nail involvement.