Not true about osteogenesis imperfecta

Clinical features of osteogenesis imperfecta:- *Blue sclera * Dentinogenesis imperfecta *Generalized osteoporosis *Osteoporosis given rise to bowing and multiple fractures. Fracture are usually due to tril trauma but surprisingly heal well. *Radiology shows Wormian bones in the skull. Radiographic features vary according to the type of disease and its severity and include osteopenia and fractures, which may heal with florid callus formation, mimicking osteosarcoma. 1 Bones are thin and under-tubulated (gracile), normal in length or shoened, thickened and deformed by multiple fractures. 2 Intra-sutural (Wormian) bones can be identified on skull radiographs. OSTEOGENISIS IMPERFECTA : # It is probably the most common form of skeletal dysplasia requiring substantial ohopaedic care. # Although the disease is usually apparent at bih or in childhood, more mild forms of the disease may not become apparent until adulthood, when affected individuals may present with insufficiency fractures and osteopenia. # In the more severely affected fetuses antenatal diagnosis may often be made in the second trimester on the basis of shoened long bones with multiple fractures. # The thorax tends to be sho but not narrow. Pathophysiology In most cases, 01 is caused by a dominant mutation in the COLIA I or the COLIA 2 genes that encode type I collagen. Fewer than 10 percent of 01 cases are believed to be caused by recessive mutations in other genes in the collagen pathway. Here is the production of abnormal collagen I molecules as well as a decrease in the production Of normal collagen I molecules. This results from mutations in the loci coding for pro-a 1 and pro-a 2 chains which form the helical structure of collagen 1. Ref:Maheshwari 9th/e p.306