MEN (General Swiss-German Mennonite)

Inheritance: autosomal dominant
Genes: CBFA1

CLCD
CCD

Open skull sutures
Hypoplasia
Absence of the clavicles
Dental anomalies
Short middle phalanx of the 5th fingers
Vertebral malformations

Cleidocranial Dysostosis

Clinical Characteristics

General description (for patients):

CCD is a rare disorder of bone and tissue formation.  The skull bones may not fuse normally and the clavicle bones may be malformed.  If the vertebrae are involved, scoliosis develops.  Pelvic bones may be wide.  Teeth often erupt late and extra teeth are sometimes seen.  There is an increased risk of pulmonary, sinus, and ear infections.

Medical description:  

This is a skeletal and dental malformation disorder.  The primary clinical features result from delayed and underossification affecting teeth, skull, pelvis, extremities and digits.  The phenotype is highly variable, though, which makes the inheritance pattern uncertain.  For example, some patients may have only dental anomalies which, if minor, are easily missed.  Delayed dentition of both deciduous and permanent teeth is common and the clavicle is hypoplastic or even aplastic.  Skull sutures may remain open for an abnormal length of time.  Vertebral malformations can lead to scoliosis and iliac bones are wide.  The middle phalanx of the 5th and sometimes 2nd fingers can be short.  Susceptibility to respiratory, sinus, and middle ear infections has been reported.

Genetics:  

A mutation in the transcription factor coding gene, CBFA1, located on chromosome 6 (6p21) seems to be responsible.  A single Mennonite family (of unknown origin) has been reported in which the father (and three relatives) only had dental anomalies while two of his four offspring had evidence of the classical CCD syndrome.  All individuals had a mutation in the ‘runt’ domain of the CBFA1 gene.  This seems to be an autosomal dominant disorder with wide variation in expression.

Treatment:  

The primary treatment consists of correction of abnormal dentition to ensure proper occlusion and prevent further oral and jaw malformations.  Monitoring and prompt treatment of infections are important.

Prognosis:  

Excellent

Ancillary treatments and support:

Pulmonary hygiene

Specialists and specialty centers:

Dentist, orthopedist

References:

Zhou, G., Chen, Y., Zhou, L., Thirunavukkarasu, K., Hecht, J., Chitayat, D., Gelb, B.D., Pirinen, S., Berry, S.A., Greenberg, C.R., Karsenty, G., and Lee, B.:  CBFA1 mutation analysis and functional correlation with phenotypic variability in cleidocranial dysplasia.  Hum. Molec. Genet. 8: 2311-2316, 1999.  PubMed ID: 10545612

Cooper, S..C., Flaitz, C.M., Johnston, D.A., Lee, B, and Hecht, J.T.:   A natural history of cleidocranial dysplasia.  Am. J. Med. Genet.  104: 19-26, 2001.  PubMed ID: 11746020

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