Osteogenesis imperfecta (OI), one of the most common skeletal dysplasias, is inherited via autosomal dominant mutation(s). It is produced by defective biosynthesis of type I collagen, which results in brittle, osteoporotic bones that are easily fractured. Osteogenesis imperfecta is also known as Lobstein disease, brittle-bone disease, blue sclera disease, and fragile bone disease.

Osteogenesis imperfecta is estimated to occur in 1:20,000 to 1:30,000 births.

Type I collagen occurs naturally as a triple helix whose constituents are two copies of the α ₁-chain and one copy of the α ₂-chain. The pro–α ₁-chain is encoded by the COL1A gene located on chromosome17, whereas the pro–α ₂-chain is encoded by the COL2A gene on chromosome 2. Quantitative defects of type I collagen are the result of mutations on the COL1A gene. Qualitative defects of type I collagen result from mutations of either the COL1A or COL2B gene, producing a mixture of both normal and abnormal collagen chains. The disease does not exhibit any predilection for a particular race, ethnic group, or gender.