The aim of this study was to analyze the CBFA1 gene in a phenotypically variable family with autosomal dominant cleidocranial dysplasia (CCD). Five members of a family with CCD were characterized clinically. X-rays and photographs of the two clinically affected family members were taken. The genotype of all five affected family members was determined with the use of single strand conformation polymorphism (SSCP) and direct sequencing. A point-mutation in exon 2 (R148G) was detected in a patient with the full-blown clinical phenotype. His son, demonstrating the same mutation, showed only the dental CCD characteristics. No mutation could be found in the three clinically healthy family members. To conclude, a missense mutation in the CBFA1 gene was detected in a family with variably expressed CCD syndrome. A detailed clinical examination is necessary to detect minimally affected gene mutation carriers.