HISTORY
A 3-year-old boy who presents with blue sclerae and a history of tibial fracture following a minor trauma (jump from a height of less than 18 inches). Has a long-standing complaint of back pain. Mother remarks that the boy bruises easily. Medical history otherwise unremarkable.
Not currently taking any medications or vitamins. Was breast-fed for 2 months and was then switched to a regular vitamin D-fortified infant formula. Has not received calcium or vitamin D supplements since starting regular cow's milk and solid food. Currently has a good intake of dairy products.
Patient's mother had multiple fractures throughout her childhood and adolescence. No recent fractures. Mother has had significant back pain since her first pregnancy; also has mild hearing loss and blue sclerae. An 11-month-old healthy sister also noted to have blue sclerae.
PHYSICAL EXAMINATION
Child appears well. Height, just below the 50th percentile; weight, close to the 75th percentile. No dysmorphic features. Results of cardiovascular and abdominal examinations, normal. No skeletal deformity. Hyperflexible joints. Extensive hematomas of varying ages over his shins.
The hereditary disorder osteogenesis imperfecta—commonly known as brittle bone disease—is characterized by excessive fragility of bones and weakness of tissues rich in type I collagen(Drug information on collagen).1 Other major clinical features include skeletal deformity, short stature, dentinogenesis imperfecta, blue sclerae, laxity of ligaments, and hearing loss.2 There are 7 different types of osteogenesis imperfecta: the severity of the clinical presentation varies to some degree among these types.
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