RUNX2 gene status in a cleidocranial dysplasia patient without supernumerary teeth.
This study sought to perform mutational analysis of the RUNX2 gene in an 8-year-old girl with a diagnosis of cleidocranial dysplasia (CCD) without supernumerary teeth (proband) and her parents, plus in age and gender matched control subjects. Ethical approval and informed consent was obtained for this study. Blood samples were obtained and the isolated DNA was used to amplify exons 0-7 of the RUNX2 gene using specific primers, which was subsequently sequenced. No mutations were identified in the coding regions of the RUNX2 gene. The absence of supernumerary teeth in this individual with CCD demonstrates that there are variations in the phenotypes and mere absence of mutations does not imply that CCD phenotype is not governed by RUNX2 gene as only two-thirds of the individuals exhibiting a CCD phenotype would reveal a RUNX2 mutation; therefore, the influence of copy number variations including large insertions, intragenic deletions, duplications, and inversions of genes cannot be excluded completely.