Major keratinocyte cell envelope protein. Defects in LOR are a cause of progressive symmetric erythrokeratodermia (PSEK). Erythrokeratodermas are a group of disorders characterized by widespread erythematous plaques, either stationary or migratory, associated with features that include palmoplantar keratoderma. PSEK is characterized by erythematous and hyperkeratotic plaques. Defects in LOR are the cause of Vohwinkel syndrome with ichthyosis (VSI); also known as loricrin keratoderma (LK) or mutilating keratoderma with ichthyosis. VSI is an ichthyotic variant of Vohwinkel syndrome (VS) characterized by progressive symmetric erythrokeratoderma or congenital ichthyosiform erythroderma born as a collodion baby. Common clinical features include hyperkeratosis of the palms and soles with digital constriction. Note: This description may include information from UniProtKB.