AQP5 pathogenic variants induce palmoplantar keratoderma Bothnia type in two Chinese families.

Palmoplantar keratoderma Bothnia type (PPKB) is caused by AQP5 pathogenic variants. The mechanisms of this disease and the genotype-phenotype correlation are still not fully understood. We report two pedigrees with PPKB caused by a recurrent variant c.367A>T and a novel variant c.530T>A in the AQP5 gene, respectively. We also summarize the cases with AQP5 variants identified, and found that there seemed to be no significant genotype-phenotype correlation of this disease. Moreover, we noticed that the epidermis of the patient had strong proliferation and immature differentiation potential as well as recognizing the possible important role of TRPV4 in the pathogenesis of PPKB.