In support of this is that siRNA knockdown of the calcium transporter ATP2C1 gene, mutated in the inherited skin blistering disease Hailey-Hailey disease, causes an increase in the expression of Claudins 1 and 4, and loss of cell-surface expression of tight junction proteins (Raiko et al., 2012). Here, CLDN1 is linked to Hailey-Hailey disease.