Laxity of ligaments results in hyper mobile joints and an increased incidence of joint dislocation. Classifications Most widely accepted classification is the Sillence classification based on clinical, genetic, and radiographic parameters. This has a numeric classification, types I to IV, with several modifiers. Types I and IV were thought to be transmitted by an autosomal dominant mode and types II and III by an autosomal recessive mode. Dental findings were used to further subtype i.e., A without and B with dentinogenesis imperfecta.
Fractures occur in later childhood and decrease toward adolescence.
Clinical features include bone fragility, blue sclerae, and onset of fractures with birth, Type A without dentinogenesis imperfecta and Type B with dentinogenesis imperfecta. Type II is lethal in the perinatal period with many of the mutations occurring in the glycine residues of type I collagen. Clinical features include death in perinatal period, dark blue sclerae, concertina femur, and beaded ribs. Type III Osteogenesis Imperfecta is the severe form, with fractures occurring at birth. The molecular basis for this type of OI has not been as fully characterized as it has for the other types.