Gene mutations and chromosomal abnormalities in syndromes with tooth agenesis

Bimaxillary fixed implant-supported zirconium oxide prosthesis therapy of an adolescent patient with non-syndromic oligodontia and two WNT10 variants: a case report

Introduction and importance

Oligodontia is a rare genetic condition characterized by more than six congenitally missing teeth, either as an isolated non-syndromic condition or in association with other genetic syndromes. The impact of WNT10A variants on dental development increases with the presence of the c.321C>A variant and the number of missing teeth.

Case presentation

A 21-year-old man with non-syndromic oligodontia was diagnosed at 15 years of age with misaligned teeth, speech problems, and the absence of 24 permanent teeth. Interdisciplinary collaboration between specialists was initiated to enable comprehensive treatment. DNA analysis confirmed that the patient was a carrier of the known pathogenic WNT10A variant c321C>A and WNT10A variant c.113G>T of unknown clinical significance.

Clinical discussion

Dental implants are a common treatment; however, bone development challenges in adolescent patients with non-syndromic oligodontia necessitate careful planning to ensure implant success. Many WNT variants play crucial roles in tooth development and are directly involved in non-syndromic oligodontia, especially the WNT10 variant c.321C>A.

Conclusion

A full-arch implant-supported monolithic zirconia screw-retained fixed prosthesis is a viable treatment option for young adults with non-syndromic oligodontia. Further studies are needed to clarify the possible amplifying effect of the WNT10A variants c321C>A and c.113G>T on the pathogenic phenotype of non-syndromic oligodontia.

Identification of novel candidate genes associated with non-syndromic tooth agenesis in Mongolian families

OBJECTIVES

This study aimed to identify genetic variants associated with non-syndromic tooth agenesis (TA) in nine families from Mongolia using whole-exome sequencing (WES) and bioinformatics analysis.

MATERIAL AND METHODS

The study enrolled 41 participants, including three inherited and six non-inherited families. WES analysis was performed on 14 saliva samples from individuals with non-syndromic TA. The potential candidate genes were identified through variant filtering and segregation analysis. The filtered variants were then analyzed in silico mutation impact analysis.

RESULTS

WES analysis identified 21 variants associated with TA, and 5 of these variants met all filtering criteria. These variants were located in the exome region of MAST4, ITGA6, PITX2, CACNA1S, and CDON genes. The variant in PITX2 was found in eight participants from inherited and non-inherited families, while the MAST4 variant was identified in 6 participants from inherited families.

CONCLUSIONS

The study identified various genetic variant candidates associated with TA in different family groups, with PITX2 being the most commonly identified. Our findings suggest that MAST4 may also be a novel candidate gene for TA due to its association with the Wnt signaling pathway. Additionally, we found that five candidate genes related to focal adhesion and calcium channel complex were significant and essential in tooth development.

CLINICAL RELEVANCE

Identifying new pathogenic genes associated with TA can improve our understanding of the molecular mechanisms underlying the disease, leading to better diagnosis, prevention, and treatment. Early detection of TA based on biomarkers can improve dental management and facilitate orthodontic and prosthetic treatment.

Count Me in, Count Me out: Regulation of the Tooth Number via Three Directional Developmental Patterns

Tooth number anomalies, including hyperdontia and hypodontia, are common congenital dental problems in the dental clinic. The precise number of teeth in a dentition is essential for proper speech, mastication, and aesthetics. Teeth are ectodermal organs that develop from the interaction of a thickened epithelium (dental placode) with the neural-crest-derived ectomesenchyme. There is extensive histological, molecular, and genetic evidence regarding how the tooth number is regulated in this serial process, but there is currently no universal classification for tooth number abnormalities. In this review, we propose a novel regulatory network for the tooth number based on the inherent dentition formation process. This network includes three intuitive directions: the development of a single tooth, the formation of a single dentition with elongation of the continual lamina, and tooth replacement with the development of the successional lamina. This article summarizes recent reports on early tooth development and provides an analytical framework to classify future relevant experiments.