RESUMO
Objective @#This article explores the relationship between congenital tooth agenesis and related gene mutations, providing a reference for early diagnosis of the disease.@*Methods @# Clinical and radiographic examinations of a rare case of congenital tooth agenesis were conducted to evaluate the abnormal morphology and quantity of the teeth, as well as the overall health of the patient. Bidirectional sequencing of the PAX9 and MSX1 genes and whole-exome sequencing were conducted to identify potential genetic abnormalities. Sanger sequencing of the newly discovered mutation site was performed on the proband's son. Subsequently, the impacts of the mutations were evaluated through computational tools and a cell-based gene transfection assay. @*Results @#This is a rare case of tooth agenesis characterized by a congenitally missing first molar, a second molar with one single root and a supernumerary second premolar in the right mandibular dentition. The c.717 C>C/T in PAX9 is synonymous. The c.119C>G in MSX1 is a missense mutation predicted to be “benign” by Polyphen. Through whole-exome sequencing, we found a novel mutation, c.637-7 C>A in intron 3 of the WNT6 gene, which is predicted by MAXENT to influence the splicing of mRNA. Both the proband and his son carry this mutation. A cell-based gene transfection assay demonstrated that it did not alter the mRNA splicing of WNT6. @* Conclusion @#The interaction between single nucleotide polymorphisms may contribute to congenital tooth agenesis.