Agenesis of all third molars in two half siblings

Tooth agenesis is one of the most common dental anomalies and is influenced by factors including patient genetics. Although there are several specific genes associated with certain patterns of agenesis, there does not seem to be a genetic pattern identified to date that is associated with isolated complete third molar agenesis. This report presents two half-siblings who both express complete agenesis of third molars despite the fact that their shared parent does not express the same phenotype. The case discussion focuses on addressing the potential genetic possibilities including autosomal dominant inheritance and variable expressivity of a mutation.  There remains an uncertainty to the exact gene involved. Potential options include WNT10A and PAX9. The affected individuals are not needing extractions or experiencing complications due to the presence of third molars.  However, the concern remains that there is the potential for more severe expression of the mutation in future generations