COL1A1 gene encodes pro-alpha1 chains of type I collagen. Type I collagen is the most abundant and widely expressed collagen in humans, found in most connective tissues, especially in bone, cornea, dermis, and tendon. It is a heterotrimer comprising two alpha 1 chains and one alpha 2 chain.
Mutations in this gene are associated with a variety of conditions, including osteogenesis imperfecta types I-IV, Ehlers-Danlos syndrome type VIIA, Ehlers-Danlos syndrome Classical type, Caffey Disease and idiopathic osteoporosis.