Understanding the implications of the PAX9 gene in tooth development.

Aim: Tooth agenesis is characterised by the congenital absence of one or more teeth. The Pax9 gene has been associated with nonsyndromic forms.
Materials and Methods: To investigate the molecular mechanisms, we evaluated specific haplotypes frequency in exon 3 of the Pax9 gene in 26 patients and 21 controls, using an Italian population.
Results: Presence of His239His and the Ala240Pro were confirmed in exon 3 of the Pax9 gene. A frequency of 20.2€ of the T allele at position 717 and a C frequency of 33€ of Ala240Pro polymorphism, that reached 40.5€ in the control group, were observed. The 39 C/C-240 C/C or G/Chaplotype which we defined Pax9hapl a had a proportion of 61.9€ in control individuals. The frequency of Pax9hapl a tested in the patients was different from controls, being 81.3€ in normalcy and 18.8€ in oligodontia (p<0.05).
Conclusion: Our observations suggest that Pax9hapl a may have a protective effect against sporadic oligodontia.