Molecular mechanisms in osteogenesis imperfecta

Some types of mutation may lead to reduced
production of pro!1(I) (1 and 2), e.g., deletion of
a COL1A1 allele, a transcription or splicing defect,
or faulty formation of collagen fibrils. The
relative excess of pro!2(I) molecules becomes
degraded. Thus, less procollagen than normal is
formed, but it is not defective. Numerous other
types of mutations can lead to defective procollagen
(3). Mutations in the pro!1(I) gene are
more severe than mutations in the pro!2(I)
gene because a greater amount of defective collagen
is formed.