Patterns of Dental Agenesis Highlight the Nature of the Causative Mutated Genes

The most common outcome of defective dental morphogenesis in human patients is dental agenesis (absence of teeth). This may affect either the primary or permanent dentition and can range from 5 or fewer missing teeth (hypodontia), 6 or more (oligodontia), to complete absence of teeth (anodontia). Both isolated and syndromic dental agenesis have been reported to be associated with a large number of mutated genes. The aim of this review was to analyze the dental phenotypes of syndromic and nonsyndromic dental agenesis linked to gene mutations. A systematic review of the literature focusing on genes ( MSX1, PAX9, AXIN2, PITX2, WNT10A, NEMO, EDA, EDAR, EDARADD, GREMLIN2, LTBP3, LRP6, and SMOC2) known to be involved in dental agenesis was performed and included 101 articles. A meta-analysis was performed using the dental phenotypes of 522 patients. The total number and type of missing teeth were analyzed for each mutated gene. The percentages of missing teeth for each gene were compared to determine correlations between genotypes and phenotypes. Third molar agenesis was included in the clinical phenotype assessment. The findings show that isolated dental agenesis exists as part of a spectrum of syndromes for all the identified genes except PAX9 and that the pattern of dental agenesis can be useful in clinical diagnosis to identify (or narrow) the causative gene mutations. While third molar agenesis was the most frequent type of dental agenesis, affecting 70% of patients, it was described in only 30% of patients with EDA gene mutations. This study shows that the pattern of dental agenesis gives information about the mutated gene and could guide molecular diagnosis for geneticists.

Rare diseases with oral components: care course and quality of life

AIM

To describe links between the care course of individuals suffering from rare diseases and socio-behavioural risk factors and to ascertain the impact of dental conditions on the quality of life.

DESIGN

A cross-sectional comparative study involving self-reported questionnaire was performed. Care course was evaluated using predisposing, enabling and needs factors. The impacts of dental conditions on quality of life were measured with the OHIP 14 questionnaire. Proportions were compared by Chi-square test. Logistic regression for multivariate analysis assessed statistical association between variables.

RESULTS

Responses were received from 355 subjects (mean age 36.9 years, 67.6% females). Thirty-three rare diseases were recorded. Respondents were classified as group A, individuals suffering from rare diseases with a dental component (n=207, 58.3%), and group B, without dental component. Group A reported earlier diagnosis, more positive attitude toward dentists, functional limitation and higher prosthetic treatment needs. Only 17.4% of subjects having fewer than 20 teeth wear prosthetics. A higher percentage of individuals claiming pain, physical disability, psychological discomfort and social disability, was found among group B (p<0.001). Logistic regression analysis retained two impact factors: psychological disability (Exp(B)=8.66; 95% CI 1.86-40.34) and social wellbeing (Exp(B)=0.06; 95% CI 0.02-0.215).

CONCLUSION

Rare diseases with a dental component benefited from earlier identification of symptoms. Dentists could contribute to patients' quality of life by helping in early diagnosis, reducing functional limitation and improving social wellbeing.