E220K

E220K refers to a specific variant of the protein Keratin 1 (KRT1). Keratins are intermediate filament proteins that provide structural support to epithelial cells. KRT1 is a type II keratin found in the epidermis, hair, and nails. Mutations in the KRT1 gene can lead to a variety of skin disorders.

The E220K mutation specifically involves a substitution of glutamic acid (E) with lysine (K) at the 220th amino acid position of the KRT1 protein. This alteration can disrupt the keratin filament network, leading to cellular fragility and impaired skin barrier function.

The E220K mutation is primarily associated with autosomal dominant forms of ichthyosis, a group of skin conditions characterized by dry, scaly skin. It is a significant cause of epidermolytic ichthyosis (EI), also known as bullous ichthyosis or ichthyosis bullosa of Siemens. Individuals with this mutation often present with blistering of the skin, particularly in infancy, and a thickened, scaly appearance. The severity can vary, but the hallmark is the fragility of the epidermis, making it prone to rupture and infection. Genetic testing can confirm the presence of the E220K mutation in individuals suspected of having these conditions.