It is worth noting that the clinical features in families with variants in the same gene AQP5 varied in severity: in the PPK1 family with the AQP5 (NM_001651.4): c.369C>G (p.(Asn123Lys)) variant we observed soft yellow diffuse palmoplantar keratoderma, keratolysis, and erythematous plaques with a clear demarcation line on the borders of the affected zones. The gene discussed is AQP5; the disease is diffuse palmoplantar keratoderma.