Erythrokeratodermia variabilis (also known as "Erythrokeratodermia figurata variabilis," "Keratosis extremitatum progrediens," "Keratosis palmoplantaris transgrediens et progrediens," "Mendes da Costa syndrome," "Mendes da Costa type erythrokeratodermia," and "Progressive symmetric erythrokeratoderma") is a rare autosomal dominant disorder that usually presents at birth or during the first year of life. To date, it is thought to be caused by mutations in genes encoding for connexin channels proteins in the epidermis, leading to the misregulation of homeostasis in keratinocytes.

One type is characterized by generalized, persistent, brown hyperkeratosis with accentuated skin markings, while a second type is localized, with involvement that is limited in extent and characterized by sharply demarcated, hyperkeratotic plaques.

It can be associated with GJB3

GJB3

Gap junction beta-3 protein is a protein that in humans is encoded by the GJB3 gene.- Function :This gene is a member of the connexin gene family. The encoded protein is a component of gap junctions, which are composed of arrays of intercellular channels that provide a route for the diffusion of...

 and GJB4

GJB4

Gap junction beta-4 protein is a protein that in humans is encoded by the GJB4 gene....

.

It was characterized in 1925.