Short middle fifth phalanges, sometimes causing short and wide fingers. Vertebral abnormalities. On rare occasions, brachial plexus irritation can occur. Scoliosis, spina bifida and syringomyelia have also been described.Other features are: parietal  bossing, basilar invagination (atlantoaxial impaction), persistent metopic suture, abnormal  ear structures with hearing loss, supernumerary ribs, hemivertebrae with spondylosis,  small and high scapulae, hypoplasia of illiac bones, absence of the pubic bone, short / absent fibular bones, short / absent  radial bones, hypoplastic terminal phalanges. Genetics
CCD is usually autosomal dominant, but in some cases its cause is not known. The main mechanism is thought to involve haploinsufficiency caused by mutations in CBFA1 (also known as Runx2), a gene located on the short arm of chromosome 6 (6p21), which encodes a transcription factor required for the differentiation of stem cells into osteoblasts. This results in delayed ossification of midline structures of the body and ensuing defects in membranous and endochondral bone formation. Diagnosis
Different features of the dysostosis are significant. Radiological imaging helps confirm the diagnosis. During gestation (pregnancy), clavicular size can be calculated using available nomograms. Wormian bones can sometimes be observed in the skull.Diagnosis of CCD spectrum disorder is established in an individual with typical clinical and radiographic findings and/or by the identification of a heterozygous pathogenic variant in RUNX2 (CBFA1). Treatment
Around 5 years of age, surgical correction may be necessary to prevent any worsening of the deformity. If the mother has dysplasia, caesarian delivery may be necessary. Craniofacial surgery may be necessary to correct skull defects.
Cleidocranial dysostosis (CCD), also called cleidocranial dysplasia, is a birth defect that mostly affects the bones and teeth. The collarbones are typically either poorly developed or absent, which allows the shoulders to be brought close together. The front of the skull often does not close until later, and those affected are often shorter than average. Other symptoms may include a prominent forehead, wide set eyes, abnormal teeth, and a flat nose. Symptoms vary among people; however, intelligence is typically unaffected.The condition is either inherited from a persons parents or occurs as a new mutation. It is inherited in an autosomal dominant manner. It is due to a defect in the RUNX2 gene which is involved in bone formation. Diagnosis is suspected based on symptoms and X-rays with confirmation by genetic testing. Other conditions that can produce similar symptoms include mandibuloacral dysplasia, pyknodysostosis, osteogenesis imperfecta, and Hajdu-Cheney syndrome.Treatment includes supportive measures such as a device to protect the skull and dental care. Surgery may be performed to fix certain bone abnormalities. Life expectancy is generally normal.It affects about one per million people. Males and females are equally commonly affected. Modern descriptions of the condition date to at least 1896. The term is from cleido meaning collarbone, cranial from the Greek κρανιὀς meaning skull, and dysostosis meaning formation of abnormal bone. Signs and symptoms
Cleidocranial dysostosis is a general skeletal condition so named from the collarbone (cleido-) and cranium deformities which people with it often have.