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Cleidocranial Dysplasia

Also known as: Cleidocranial Dysostosis

Background

Cleidocranial dysplasia (CCD) is a hereditary congenital (meaning it is present at birth) skeletal condition characterised by delayed closure of the cranial vault sutures, (the seams between the bones which make up the cranial vault (skull)), hypoplastic (under developed) or aplastic (absent) clavicles (collar bones) and multiple dental anomalies. It was described independently by SchItuthauer (1871) and Marie and Sainton (1897).

Credits

Medical text written November 2010 by Mr Robert D Evans, Consultant Orthodontist, Great Ormond Street Hospital, London, UK.

What are the symptoms?

The most prominent clinical features are:

  • a combination of aplasia or hypoplasia of one or both the clavicles. This permits a wide range of shoulder movements that would not occur normally, including the ability to move the shoulders in front of the chest
  • large wide open fontanelles (soft spots in a baby's head) at birth, which may remain open throughout life. The forehead is broad and flat. The head shape is described as brachcephalic, meaning that the head is disproportionately wide
  • the skull base is short and the maxilla (midface or upper jaw) hypoplastic
  • the eyes are wide set and prominent
  • the dentition is severely affected - delayed or failure of eruption of both the primary and secondary teeth; delayed exfoliation (loss) of the primary teeth and the presence of numerous supernumerary (extra) teeth.

Other skeletal characteristics identified include:

  • short, tapering fingers and short broad thumbs
  • pes planus (flat feet)
  • genu valgum (knock knees)
  • scoliosis
  • short stature.

Conductive hearing loss due to middle ear effusions (presence of fluid in the middle ear) can occur. Recurrent sinus infections are common. A tendency for obstructive sleep apnoea (OSA) has been reported. Intelligence is normal compared to unaffected siblings.

What are the causes?

A total of 60 to 70 per cent of individuals with a clinical diagnosis of CCD have a mutation of RUNX2, which is located on chromosome 6.

How is it diagnosed?

Diagnosis is based on the clinical and radiographic findings, such as typical characteristics being visible on X-ray. Genetic testing can confirm the presence of a mutation in RUNX2.

How is it treated?

Treatment for the condition is symptomatic, meaning that the symptoms are addressed to improve an individual's quality of life. Care should be coordinated via a paediatrician who will arrange a referral to either craniofacial or neurosurgery specialists, an ear, nose and throat (ENT) surgeon or audiological (hearing) physician. Hearing should be screened and followed up with regular assessments. A sleep study may be indicated if OSA is suspected. A referral to an orthodontist (for the management of the dental problems) before the age of six years is highly recommended.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
CCD is transmitted as an autosomal dominant trait. A mutation of RUNX2 gene is responsible in 60 to 70 per cent of cases.

Prenatal diagnosis
Genetic testing for at risk families is possible if the causative mutation is known.

Is there support?

There is no support group for cleidocranial dysostosis/dysplasia in the UK. Cross referrals to other entries in The Contact a Family Directory are intended to provide relevant support for these particular features of the disorder. Organisations identified in these entries do not provide support specifically for cleidocranial dysostosis/dysplasia.

Families can use Contact a Family's freephone helpline for advice, information and, where possible, links to other families. Contact a Family's web-based linking service can be accessed at community.cafamily.org.uk