Osteogenesis imperfecta (see Byers, 1993, https://omim.org/entry/166200) is characterized chiefly by multiple bone fractures, usually resulting from minimal trauma. Affected individuals have blue sclerae, normal teeth, and normal or near-normal stature (for growth curves, see Vetter et al., 1992). Fractures are rare in the neonatal period; fracture tendency is constant from childhood to puberty, decreases thereafter, and often increases following menopause in women and after the sixth decade in men. Fractures heal rapidly with evidence of a good callus formation, and, with good orthopedic care, without deformity. Hearing loss of conductive or mixed type occurs in about 50% of families, beginning in the late teens and leading, gradually, to profound deafness, tinnitus, and vertigo by the end of the fourth to fifth decade. Additional clinical findings may be thin, easily bruised skin, moderate joint hypermobility and kyphoscoliosis, hernias, and arcus senilis. Mitral valve prolapse, aortic valvular insufficiency, and a slightly larger than normal aortic root diameter have been identified in some individuals (Hortop et al., 1986), but it is not clear that these disorders are significantly more frequent than in the general population.

Radiologically, wormian bones are common but bone morphology is generally normal at birth, although mild osteopenia and femoral bowing may be present. Vertebral body morphology in the adult is normal initially, but often develops the classic ‘cod-fish’ appearance (Steinmann et al., 1991).