A comprehensive review on Ichthyosis

The Ichthyosis are a large, clinically, genetically, and etiologically heterogeneous group of disorders of cornification due to abnormal differentiation and desquamation of the epidermis. Although they differ in clinical features, inheritance, and structural and biochemical abnormalities of the epidermis, they often pose a diagnostic challenge. These skin disorders are the result of the presence of excessive amounts of dry surface scales due to marked keratinization or cornification, as a consequence of abnormal epidermal differentiation and metabolism. To date, five major types of IT have been officially described, which include ichthyosis vulgaris, lamellar ichthyosis, epidermolytic hyperkeratosis, congenital ichthyosiform erythroderma, and X-linked ichthyosis. These can be differentiated based on the general clinical manifestations, histological findings, as well as genetic makeup. The molecular findings reveal the functional importance and interactions of many different epidermal proteins and metabolic pathways, including major structural proteins (keratins, loricrin), enzymes involved in lipid metabolism, peroxisomal transport and processing and DNA repair.