A three-year-old patient with easy bruising and a lifelong history of pathologic fractures due to a genetic condition affecting collagen synthesis is MOST likely to be diagnosed with which condition?

• A. Pediatric osteoporosis
• B. Osteogenesis imperfecta
• C. Osteomalacia
• D. Osteopetrosis

Answer: (B)

Osteogenesis imperfecta is the result of a genetic defect in type I collagen synthesis, the main organic matrix of bone. When collagen is abnormal, the bone matrix is weak, so bones fracture easily with minimal or no trauma, producing the lifelong fractures described. Easy bruising also fits, since collagen is important in connective tissues and blood vessel walls, making them more fragile. This combination in a young child strongly suggests a collagen-related bone fragility disorder rather than issues of mineralization or bone turnover alone.

Pediatric osteoporosis involves low bone mass but isn’t driven by a primary collagen defect. Osteomalacia is due to defective mineralization from vitamin D deficiency, leading to rickets-like changes rather than a dominant collagen issue. Osteopetrosis features overly dense bones from osteoclast dysfunction, not a collagen synthesis problem.