Bone Abstracts

Background: Cleidocranial dysplasia (CCD) is an ultra-rare (1/1,000,000) genetic bone disorder, characterized by hypoplastic or aplastic clavicles, persistence of wide-open fontanelles and multiple dental abnormalities. It is caused by mutations in the RUNX2 gene, involved in the differentiation of osteoblasts.

Presenting Problem: A case of a 13 year-old girl with a clinical diagnosis of CCD is reported. Her clavicles were hypoplastic and her shoulders could be approximated anteriorly. Her fontanelles closed at the age of three years and she had severe dental health issues, including an operation of the left mandible to remove a supernumerary tooth. The presenting complaint was the presence of ‘clicky knees’.

Clinical management: Full bone health evaluation, work up for comorbidities and comprehensive dental assessement were performed. She had short trunk, scoliosis, pes planus and genu valgum, small thorax, hyperextension of knee and elbow joints and numerous naevi. Her bone mineral density was low-normal and the basic laboratory bone profile was unremarkable. The main imaging findings were: wormian bones of the skull, hypoplastic clavicles, osteopenia, cone-shaped thorax, slender bones and wide pubic symphysis. Her audiogram was normal, as was her cognition. Her dental assessment revealed crowded mixed dentition, moderate dental hygiene, dental caries and absence of the lower right lateral incisor. Her orthopantomography showed supernumerary teeth on the right mandible and a two-years delay of her dental age. Her dental treatment plan includes restorations of the caries lesions, orthodontic treatment, surgical removal of the supernumerary teeth to allow eruption of the permanent ones and recalls every 3–4 months. Advice was also given on vaccinations, exercise and physiotherapy for muscle strengthening and healthy diet. A genetic test for confirmation of the clinical diagnosis is being scheduled and she is being reviewed on an annual basis.

Discussion: The effective management of the dental anomalies is very important for CCD patients and focuses on achievement of optimal function and aesthetics. What is equally crucial is the comprehensive and regular skeletal assessment, given that RUNX2 plays an important role in bone formation. Finally, detailed surveillance for complications such as deafness, growth failure and recurrent respiratory infections is necessary.

Disclosure: The authors declared no competing interests.