Cleidocranial dysostosis

Cleidocranial dysostosis (CCD), also known as cleidocranial dysplasia, is a rare skeletal dysplasia with predominantly membranous bone involvement, which carries an autosomal dominant inheritance ⁴.

Clinical presentation

• large head, with large fontanelles with delayed closure

• broad mandible

• supernumerary teeth

• high arched palate

• neonatal distress due to the thorax being narrowed and bell-shaped

• excessively mobile and drooping shoulders

• may have genu valgum and short fingers

Pathology

It is a rare polyostotic skeletal dysplasia caused by a mutation in the CBFA1 gene in AD inherited or sporadic mutation pattern (in approximately 40%) which is characterized by incomplete intramembranous ossification of midline skeletal structures inclusive of the clavicle as well as a defective development of the pubic bones, vertebral column, and long bones ⁵.

Radiographic features

Plain radiograph

Skull

• multiple wormian bones

• widened sagittal sutures and/or fontanelles

• premature fusion of the coronal suture (brachycephaly)

• frontal and/or parietal bossing

• basilar invagination (atlantoaxial impaction)

• persistent metopic suture

• supernumerary or abnormal teeth

• abnormal ear structures with hearing loss ⁶

Chest

• hypoplasia/aplasia of the lateral clavicle (absent clavicles): may have two separate hypoplastic segments ⁵

• supernumerary ribs

• hemivertebrae with spondylosis

• small and high scapulae

Pelvis

• hypoplasia of iliac bones

• absent/delayed ossification of the pubic bone creating the appearance of a pseudo-widening of the symphysis pubis

Limbs

• short/absent fibula

• short/absent radius

• coxa vara

• hypoplastic terminal phalanges

• pseudoepiphysis of metacarpals and metatarsal bones