Images of Memorable Cases: Cases 40, 41 & 42 These three unrelated teenaged girls had the same disease. 40, 41 & 42. Osteogenesis imperfecta An autosomal dominant disorder marked by defective formation of collagen. Its cardinal manifestations are blue sclerae, fragile bones, and deafness. The blue discoloration occurs when thinning of the sclera allows the underlying choroid to become visible. Although blue sclerae occur chiefly in osteogenesis imperfecta, they also appear occasionally in pseudoxanthoma elasticum, Ehlers-Danlos syndrome, and Marfan’s disease. Rarely, they are seen in patients with iron deficiency, rheumatoid arthritis, or myasthenia gravis.