Gap junction diseases of the skin. By Lamia Elgarhy Assistant lecturer. Gap junctions. INTRODUCTION. Gap junctions are small membrane pores that facilitate rapid intercellular communication in all vertebrate cells, and are composed of connexins .
α(GJA), β(GJB), Υ(GJC), δ(GJD), ε(GJE).
Connexon or hemichannel is composed of 6 connexins. It is homomeric if they are of one connexin type and heteromeric if more than one.
All PPK- deafness mutations seem to cluster in E1 and E2 which have some role in channel assembly and /or transport.
Bart- Pumphrey syndrome:
(H&E stain) shows compact orthokeratotic hyperkeratosis, hypergranulosis, and acanthosis of the epidermis. (f) Transmission electron micrograph demonstrating a normal-appearing gap junction plaque between granular keratinocytes.
typeIIIsyndactyly, clinodactyly and hypoplasia of the middle phalanx of the fifth digits.