(i) Increased bone fragility Minor injuries can cause fractures, and severe patients present with spontaneous fractures. Congenital type has multiple fractures at birth. Most of the fractures are of the glaucomatous type, with little displacement, mild pain, rapid healing, and reliance on subperiosteal osteogenesis to complete, thus often going unnoticed and causing malunion. The long bones and ribs are the most common sites. The deformity caused by multiple fractures further reduces the length of the bone. The tendency to fracture gradually decreases after puberty. (ii) Blue sclera is present in about 90% or more. This is due to the fact that the patient’s sclera becomes translucent and the color of the choroid beneath it can be seen. There is no abnormality in the thickness or structure of the sclera, and its translucency is due to a change in the nature of the collagen fiber tissue. (c) Deafness often occurs from 11 to 40 years of age, accounting for about 25% of the cases. It may be due to sclerosis of the ear canal and fixation of the stapes footplate attached to the oval window due to bony ankylosis, but it is also believed to be due to compression of the auditory nerve as it exits the base of the skull. (d) Excessive laxity of the joints, especially of the wrist and ankle. This is due to impaired development of collagenous tissue in the tendons and ligaments. There may also be knee valgus and flat feet. Sometimes there is habitual shoulder dislocation and dislocation of the radial head. (v) Weak muscles. (vi) Severe craniofacial dysplasia in which the head has a leathery appearance at birth. Later, the skull is broad, the parietal and occipital bones are prominent, the two temporal bulges are bulbous, the frontal bone protrudes anteriorly, the ears are pushed downward, and the face becomes an inverted triangle. Some patients are accompanied by hydrocephalus. (VII) Dental hypoplasia: The dentition is not well developed, and both milk teeth and permanent teeth may be involved. The teeth are yellow or blue-gray in color and are easily carious and fall out at an early stage. (viii) Pygmy. This is due to slightly shorter than normal development, coupled with multiple fractures of the spine and lower limbs that heal abnormally. (ix) Increased width of skin scars, which is also due to defective collagenous tissue.X-ray manifestations are mainly lack of bone mass and generalized thinning of bone. (i) In the long bones, it is manifested as slenderness, with scanty bone trabeculae that are translucent, and thin cortex like pencil drawings. The medullary cavity is relatively enlarged and may be cystic in severe cases. The ends of the bone are enlarged in a pestle shape, and multiple old or fresh fractures are seen. Some have been deformed and connected, with the diaphysis bent. Some deformities are due to pulling at the muscular attachments, such as internal rotation of the hip and bowing of the femur and tibia. In some patients, an abundance of globular bone scabs will form after a fracture, so numerous and extensive that one may misdiagnose them as osteosarcoma. Other patients have thicker bone cortex, called “thick bone type”. It is rare. Delayed calcification of the skull, thinning of the bone plates, bulging of both temporal bones, broadening of the anterior chimney, relatively dense rocky bones, and flattening of the skull base. Poor calcification of the mastoid teeth and fair development of the permanent teeth. (iii) The vertebral body is thinned and biconcave, with sparse trabeculae and compensatory biconcave disc enlargement. There may be scoliosis or kyphosis. The ribs are bent downward from the rib corners, and multiple fractures are often seen. The pelvis is triangular in shape and the pelvic cavity becomes smaller.