Developmental Disorders
Cleidocranial Dysplasia
aka CCD · Cleidocranial Dysostosis · Marie–Sainton Syndrome
Autosomal dominant skeletal dysplasia with clavicular hypoplasia, delayed cranial ossification, and multiple supernumerary teeth.
§ overviewOverview
A rare autosomal dominant skeletal disorder caused by RUNX2 (CBFA1) mutation, affecting membranous and endochondral bone.
§ etiologyEtiology
- 01Heterozygous mutation of RUNX2 gene on chromosome 6p21
- 02Impaired osteoblast differentiation
§ riskRisk Factors
- 01Family history (AD inheritance)
- 02~40% sporadic mutations
§ epidemiologyEpidemiology
≈1 in 1,000,000 live births. No sex or race predilection.
§ pathogenesisPathogenesis
RUNX2 haploinsufficiency disrupts osteoblastic transcription, producing defective intramembranous ossification of clavicles and skull, and failure of primary teeth resorption.
§ clinicalClinical Features
- 01Hypoplastic/aplastic clavicles — shoulders approximate in midline
- 02Delayed closure of fontanelles and sutures
- 03Frontal, parietal and occipital bossing
- 04Maxillary hypoplasia with relative mandibular prognathism
- 05High arched narrow palate ± cleft palate
- 06Prolonged retention of deciduous teeth
- 07Multiple unerupted permanent and supernumerary teeth
§ signsSigns & Symptoms
- 01Short stature
- 02Long neck, narrow drooping shoulders
- 03Facial disproportion
§ differentialDifferential Diagnosis
- 01Pycnodysostosis
- 02Crane–Heise syndrome
- 03Yunis–Varon syndrome
- 04Mandibuloacral dysplasia
§ histopathHistopathology
- 01Not diagnostic; dental follicles may show hyperplastic connective tissue
§ radiographicRadiographic Features
- 01OPG: multiple unerupted permanent + supernumerary teeth, retained deciduous
- 02PA skull: open fontanelles, wormian bones, hypoplastic paranasal sinuses
- 03Chest: absent/hypoplastic clavicles
§ cbctCBCT Findings
- 013D localisation of supernumerary and impacted teeth
- 02Assessment of alveolar bone height for orthosurgical planning
§ investigationsInvestigations
- 01Clinical + radiographic diagnosis
- 02Genetic testing (RUNX2)
§ classificationClassification
- 01Classical CCD
- 02Mild CCD (isolated dental features)
- 03CCD with additional features (cleft palate, brachydactyly)
§ treatmentTreatment
- 01Multidisciplinary — pediatric dentist, orthodontist, oral surgeon, prosthodontist
- 02Belfast/Toronto/Jerusalem protocols: extract deciduous + supernumerary, expose and orthodontically align permanents
- 03Implants and prostheses when growth complete
§ surgicalSurgical Management
- 01Removal of supernumerary teeth
- 02Surgical exposure & bonding of impacted permanents
- 03Orthognathic surgery for skeletal disproportion
§ complicationsComplications
- 01Failure of eruption
- 02Malocclusion
- 03Recurrent sinusitis
- 04Deafness (rare)
§ prognosisPrognosis
Excellent for lifespan. Dental rehabilitation is lifelong.
§ examKey Examination Points
- 01Ability to approximate shoulders anteriorly — pathognomonic
- 02OPG with 'crown of teeth' from multiple impactions
- 03Autosomal dominant, RUNX2 mutation
§ vivaBDS Viva Questions
- 01Which gene is mutated in cleidocranial dysplasia?
- 02Name three dental manifestations of CCD.
- 03Outline the Toronto protocol for management.
§ pearlsClinical Pearls
- 01Suspect CCD in any child with multiple supernumeraries and delayed eruption.
§ mnemonicsMnemonics
- 01CCD = Clavicles, Cranium, Dentition
§ mcqsMCQs — Assessment (1)
Question 1
The gene most commonly implicated in cleidocranial dysplasia is:
References
- Neville BW, Damm DD. Oral & Maxillofacial Pathology, 4e
- Shafer's Textbook of Oral Pathology, 9e
Draft — pending faculty review. Educational use only; verify against current guidelines and primary sources before clinical application.