GJB2 and hereditary palmoplantar keratoderma: Mutations in GJB2 encoding for Cx26 are associated with several rare syndromic deafness disorders that manifest with skin pathologies, including palmoplantar keratoderma (PPK) with deafness, Vohwinkel’s syndrome (VS), Bart-Pumphrey syndrome (BPS), keratitis-ichthyosis-deafness (KID) syndrome, and hystrix-like-ichthyosis-deafness (HID) syndrome (Srinivas et al., 2018).