All are seen are features of osteogenesis imperfecta except -

Ans. is 'c' i.e., Absent clavicle Osteogenesis imperfecta (fragilitas ossium)* Osteogenesis imperfecta, also known as brittle bone disease or Lobstein Vrolik's syndrome, is a hereditary condition characterized by fragility of bones, deafness, blue sclera, laxity of joints and tendency to improve with age.* It is a disease of defective collagen formation. Therefore, collagen - containing tissues are affected, e.g. bone, teeth, skin, tendons and ligaments.* Collagen is one of the important constituent of protein matrix of bone, i.e. osteoid.* Therefore, primary defect in bone is defective osteoid formation.* It is usually transmitted as an autosomal dominant, but in a severe variant of the disease the parents are normal and a fresh gene mutation or autosomal recessive inheritance is postulated.Clinical features of osteogenesis imperfecta* Blue sclera* Dentinogenesis imperfecta* Generalized osteoporosis* Osteoporosis given rise to bowing and multiple fractures.* Fracture are usually due to trivial trauma but surprisingly heal well.* Other features: Deafness due to otosclerosis, joint laxity, dwarfism, broad skull, poorly calcified decidual teeth (Permanent teeth are normal).* Wormain bones.