A novel PAX9 mutation causing oligodontia

- An extended family exhibiting both hypodontia and oligodontia is described.
- Mutations were found in MSX1 and PAX9 genes.
- The PAX9 mutation is novel and associated solely with the oligodontia phenotype.

IntroductionAn extended family presenting with several members affected by developmentally missing teeth was investigated by analysis of the MSX1 and PAX9 genes.Materials and methodsSaliva samples were collected and DNA extracted. Primers were designed to span the exons and intron-exon junctions of the MSX1 and PAX9 genes. These primers were optimised using gradient Polymerase Chain Reaction. The amplified fragments were sent for Sanger sequencingResultsa novel heterozygote missense mutation in exon 3 of PAX9 (c.296G > C, p.A99P), was found in two severely affected members of the family as well as a potentially pathogenic heterozygote variant (c.119C > G, p.A40G) in exon 1 of the MSX1 gene.ConclusionThe PAX9 A99P mutation is in the DNA binding domain and is predicted to be pathogenic.