The skin's major structural barrier is provided by a few layers of keratinocytes that collectively comprise the epidermis. This barrier, known as the stratum corneum, is life-sustaining, prevents loss of water from the body and withstands chemical, microbial,
immunological and ultraviolet solar assault. The synthesis of the stratum corneum is often referred to as keratinization, but because this process involves more than keratins alone, cornification is the most complete term. Cornification represents the convergence of three biochemical processes, followed by desquamation: 1) the formation and organization of intracellular keratin intermediate filaments; 2) the formation and dispersion of an intercellular lipid glue or mortar that combines the fully cornified cells together and makes the stratum corneum impermeable to many substances; and 3) the synthesis of the cornified envelope, the toughest portion of the stratum corneum that also functions to interconnect the intracellular keratin matrix with the intercellular lipid glue. Once keratinocytes have undergone complete cornification, they are called corneocytes.
Because keratins serve as the major cytoskeletal proteins of the epidermis, when the synthesis of a keratin protein is defective, the structural integrity of the affected keratinocytes and the stratum corneum they produce is affected.
Types of Cornification Disorders
Most disorders of cornification have a hereditary, metabolic or nutritional cause. The group of skin diseases with abnormal cornification includes:
Nonepidermolytic ichthyosis is
- Desquamation - exfoliation; peeling;
- Epidermis - the layer on the outside of the skin, the visible part of the skin;
- Lesion - tissue damage;
- A Heritable Keratinization Defect of the Superficial Epidermis in Norfolk Terriers
K. F. Barnhart a, K. M. Credille a, A. Ambrus a and R. W. Dunstan
- A Dissertation by Kirstin Faye Barnhart. In vitro and in vivo analysis of differential gene expression between normal Norfolk Terrier dogs and those with an autosomal recessive mutation in KRT10
- The Clinical and Morphologic Features of Nonepidermolytic Ichthyosis in the Golden Retriever