Mutation Analysis of Core Binding Factor A1 in Patients with Cleidocranial Dysplasia

• Published in: American journal of human genetics 1999-11, Vol.65 (5), p.1268-1278
• Main Authors: Quack, I., Vonderstrass, B., Stock, M., Aylsworth, AS, Becker, A., Brueton, L., Lee, PJ, Majewski, F., Mulliken, JB, Suri, M., Zenker, M., Mundlos, S., Otto, F.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Bone and Bones - diagnostic imaging; Bone and Bones - pathology; CBFA1; Cell Line; Cleidocranial dysplasia; Cleidocranial Dysplasia - diagnostic imaging; Cleidocranial Dysplasia - genetics; Core binding factor; Core Binding Factor Alpha 1 Subunit; Core Binding Factors; Diseases of the osteoarticular system; DNA Mutational Analysis; Frameshift Mutation; Green Fluorescent Proteins; Human malformation syndrome; Humans; Luminescent Proteins; Malformations and congenital and or hereditary diseases involving bones. Joint deformations; Medical sciences; Microscopy, Fluorescence; Molecular Sequence Data; Mutation, Missense; Neoplasm Proteins; Nuclear localization; Phenotype; Polymorphism, Genetic; Radiography; Recombinant Fusion Proteins; Sequence Deletion; Tooth - pathology; Transcription factor; Transcription Factors - genetics; Transfection
• ISSN: 0002-9297; 1537-6605
• DOI: 10.1086/302622

Cleidocranial dysplasia (CCD) is a dominantly inherited disorder characterized by patent fontanelles, wide cranial sutures, hypoplasia of clavicles, short stature, supernumerary teeth, and other skeletal anomalies. We recently demonstrated that mutations in the transcription factor CBFA1, on chromosome 6p21, are associated with CCD. We have now analyzed the CBFA1 gene in 42 unrelated patients with CCD. In 18 patients, mutations were detected in the coding region of the CBFA1 gene, including 8 frameshift, 2 nonsense, and 9 missense mutations, as well as 2 novel polymorphisms. A cluster of missense mutations at arginine 225 (R225) identifies this residue as crucial for CBFA1 function. In vitro green fluorescent protein fusion studies show that R225 mutations interfere with nuclear accumulation of CBFA1 protein. There is no phenotypic difference between patients with deletions or frameshifts and those with other intragenic mutations, suggesting that CCD is generally caused by haploinsufficiency. However, we were able to extend the CCD phenotypic spectrum. A missense mutation identified in one family with supernumerary teeth and a radiologically normal skeleton indicates that mutations in CBFA1 can be associated exclusively with a dental phenotype. In addition, one patient with severe CCD and a frameshift mutation in codon 402 had osteoporosis leading to recurrent bone fractures and scoliosis, providing first evidence that CBFA1 may help maintain adult bone, in addition to its function in bone development.