GJB2 and Palmoplantar keratoderma: Different alterations of the GJB2 sequence can produce a variety of clinical outcomes, including the most common non-syndromic autosomal recessive deafness, 1A type (DFNB1A, OMIM #220290), autosomal dominant deafness, type 3A (DFNA3A, OMIM #601544), as well as syndromic forms, in which hearing loss is accompanied by mild to severe skin disorders: palmoplantar keratoderma with deafness (OMIM #148350), keratitis-ichthyosis-deafness syndrome (KID, OMIM #148210), Vohwinkel syndrome (OMIM #124500), Bart–Pumphrey syndrome (OMIM #149200), and hystrix-like ichthyosis with deafness (OMIM #602540).