Skin and Connective Tissue Disorders.

Osteogenesis imperfecta (OI) is a clinically heterogeneous disorder resulting from the reduced synthesis or the accumulation of abnormal type I collagen, which is a major structural component of many connective tissues including bone. Type I collagen is a trimeric molecule composed of two α1(I) chains and one α2(I) chain, encoded by the COL1A1 and COL1A2 genes, respectively. Fibrillar collagens have a long triple helical domain composed of Gly-X-Y repeats. Glycine residues at every third position are required for the formation of the triple helical domain.1 OI is predominantly inherited in an autosomal dominant fashion and is caused by a wide variety of mutational events in either the COL1A1 or COL1A2 gene. [ABSTRACT FROM AUTHOR]