The first GJA1 mutation identified in an isolated epidermal disorder was the Cx43-G8V mutation linked to palmoplantar keratoderma and congenital alopecia-1 (PPKCA1, also called keratoderma-hypotrichosis-leukonychia totalis)22. The gene discussed is GJA1; the disease is hereditary palmoplantar keratoderma.