A novel SNP of PAX9 is associated with oligodontia

Objectives: To investigate clinical characteristics and molecular mechanisms of oligodontia, especially to identify the correlation of PAX9 with oligodontia. Methods: Panoramic radiographs, laboratory and clinical examinations , mutation analysis were carried out on the affected brother and his twin sister. Furthermore, we got out DNA from the venous blood of 54 persons composed of 11 oligodontia patients, and SNP genotyping were performed by using TaqMan-MGB probe. Results: The younger brother lacked 22 teeth including incisors, canines, premolars, and molars. His skin, hairs and sweat glands were dysplasia. No striking differences were found on chromosome shape and the density of trace element,, but the concentration of alkaline phosphatase(ALP) was higher than the reference. The detection of PAX9 gene mutation on the twin revealed that the 88th ,89th nucleic acids of exon 3 in PAX9 were two SNPs. The 88th site was C→T, still encoding histamine which belongs to same-sense mutation. The 89th site was G→C, corresponding codon changing from alanine(GCG) to proline(CCG), which belongs to missense mutation. Moreover, among 11 persons with oligodontia in 54 samples, 6 were G/C heterozygous mutation , 5 were C/C homozygous mutation in this SNP site by SNP genotyping. Conclusions: In general, we screened out possible SNP site of PAX9 in patients with oligodontia based on sequencing and SNP genotyping using TaqMan-MGB probe technique, and found that the 89th SNP site of exon 3 of PAX9 was closely relevant to oligodontia. The above discovery has not been reported until now.