ABSTRACT

keratinization is a differentiation process in which basal epidermal cells gradually mature and transform into stratum corneum cells. During keratinization, a tough, chemically resistant, cross-linked protein band is laid down just inside the plasma membrane and the whole cell flattens to a thin disc. The stratum corneum is the major barrier to water loss from the skin and to the penetration of chemical agents that come into contact with the skin. The term ichthyosis is unfortunate, as the scale of ‘modern’ fish is, in fact, mesodermal rather than ectodermal in origin. Xeroderma is seen in many patients with atopic dermatitis. Non-bullous ichthyosiform erythroderma is inherited as a rare, autosomal recessive disorder. Epidermolytic hyperkeratosis is a rare, autosomal dominant disorder of keratinization. Lamellar ichthyosis is a rare, autosomal recessive disorder of keratinization, characterized by a striking degree of hyperkeratosis but not much erythema. Tuberous sclerosis is a rare, autosomal dominant condition in which many abnormalities occur.