Cytokeratin 10 is a heterotetramer of two type I and two type II keratins. Cytokeratin 10 is generally associated with keratin 1. It is seen in all suprabasal cell layers including stratum corneum. A number of alleles are known that mainly differ in the Gly-rich region (positions 490-560). Defects in cytokeratin 10 are a cause of epidermolytic hyperkeratosis (EHK), also known as bullous congenital ichthyosiform erythroderma (BCIE) or bullous erythroderma ichthyosiformis congenita of Brocq. EHK