Hypophosphatasia Dental Feature — MFDS Part 1 MCQ

Instant feedback + full explanation. One question, done properly.

HardHuman DiseaseHypophosphatasia Dental FeatureMFDS Part 1

A 3-year-old child has spontaneously lost several mandibular primary incisors. The exfoliated teeth retain almost their full root length. There is minimal gingival inflammation and no severe periodontitis. Serum alkaline phosphatase activity is persistently below the age-adjusted reference range. Which disorder best explains these findings?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Hypophosphatasia

The diagnosis is hypophosphatasia, an inherited metabolic disorder caused by deficient tissue-nonspecific alkaline phosphatase activity. Impaired formation or mineralisation of root cementum compromises periodontal ligament attachment, producing premature loss of primary teeth that retain substantial or nearly complete roots. Persistently low age-adjusted serum alkaline phosphatase is a key discriminator. Langerhans cell histiocytosis may cause mobile, radiographically “floating” teeth through alveolar bone destruction. Papillon–Lefèvre syndrome and cyclic neutropenia cause early tooth loss in association with marked periodontitis or recurrent oral inflammation. Hypothyroidism is more typically associated with delayed dental development and eruption rather than premature root-intact exfoliation.

Reference: Lira Dos Santos EJ, Mohamed FF, Kramer K, Foster BL. Dental manifestations of hypophosphatasia: translational and clinical advances. JBMR Plus. 2025. https://pubmed.ncbi.nlm.nih.gov/39872235/