A patient presents with premature loss of teeth and an absence/defect of dental cementum, with impaired mineralization of bone and teeth. Which disorder is most likely?

Correct answer: A. Hypophosphatasia

• A. Correct. Hypophosphatasia is a rare genetic disorder of low alkaline-phosphatase activity causing defective mineralization of bone and tooth cementum, leading to premature loss of teeth (often with the root intact).
• B. Vitamin D-resistant rickets causes large pulp chambers and spontaneous abscesses, not a primary cementum-aplasia picture.
• C. Dentinogenesis imperfecta affects dentin (opalescent teeth, bulbous crowns, obliterated pulps), not cementum.
• D. Cleidocranial dysplasia causes supernumerary/unerupted teeth and absent clavicles, not cementum loss.