Evolution Favored Thick Skin over Deafness

One in a thousand individuals has congenital hearing loss, which is often traceable to homozygous mutations in the connexin 26 (GJB2) gene. Remarkably, previous study findings have suggested that heterozygous GJB2 mutations are associated with a thickened epidermis. The most frequent mutation in GJB2 is 35delG, found in 1 in 30 Mediterranean individuals and 1 in 70 northern Europeans. Researchers in Italy measured epidermal thickness in 54 obligate 35delG carriers and 240 controls. Mean epidermal thickness was more than twice as thick in the 35delG carriers.