Inheritance pattern of molar-incisor hypomineralization

Abstract The aim of this study was to investigate the segregation patterns of molar incisor hypomineralization (MIH) in families, given the evidence that its etiology is influenced by genetics. Clinically, MIH may be detected in parents and/or siblings of MIH-affected children. Our study included children with at least one first permanent molar affected by MIH (proband) and their first-degree relatives (parents and siblings). The participants were examined clinically to detect MIH, according to the European Academy of Paediatric Dentistry criteria (2003). A total of 101 nuclear families (391 individuals) were studied. Proband diagnosis was followed by MIH classification of the subject, his parents and siblings, as affected, unaffected, or unknown. Segregation analysis was performed using the multivariate logistic regression model of the Statistical Analysis for Genetic Epidemiology package, and segregation models (general transmission, environmental, major gene, dominant, codominant and recessive models). The Akaike information criterion (AIC) was used to evaluate the most parsimonious model. In all, 130 affected individuals, 165 unaffected individuals, and 96 unknown individuals were studied. Severe MIH was found in 50.7% of the cases. A segregation analysis performed for MIH revealed the following different models: environmental and dominance (p = 0.05), major gene (p = 0.04), codominant (p = 0.15) and recessive models (p = 0.03). According to the AIC values, the codominant model was the most parsimonious (AIC = 308.36). Our results suggest that the codominant model could be the most likely for inheriting MIH. This result strengthens the evidence that genetic factors, such as multifactorial complex defect, influence MIH.

Prevalence of developmental defects of enamel in children and adolescents with asthma / Prevalência de defeitos do desenvolvimento do esmalte dentário em crianças e adolescentes com asma

OBJECTIVE: This study aimed to evaluate the prevalence of developmental defects of enamel (DDEs) in relation to asthma severity, symptom onset and pharmacological treatment in pediatric asthma patients. METHODS: Children and adolescents (68 asthma patients and 68 controls), 5-15 years of age and residents of the city of Londrina, Brazil, were enrolled in the study. Medical and dental histories were collected through the use of a structured questionnaire. Each participant underwent a dental examination in which the examiner employed the DDE index. RESULTS: Of the 68 asthma group subjects, 61 (89.7 percent) presented dental enamel defects, compared with only 26 (38.2 percent) of those in the control group. Using multivariate logistic regression analysis, we estimated the risk of DDEs in permanent dentition to be 11 times higher in pediatric subjects with asthma than in those without (OR = 11.88, p = 0.0001). The occurrence of dental enamel defects correlated with greater asthma severity (p = 0.0001) and earlier symptom onset (p = 0.0001). However, dental enamel defects did not correlate with the initiation of treatment (p = 0.08) or the frequency of medication use (p = 0.93). CONCLUSIONS: Pediatric patients with severe, early-onset asthma are at increased risk of dental enamel defects and therefore require priority dental care.

OBJETIVO: Avaliou-se a prevalência de developmental defects of enamel (DDEs, defeitos de desenvolvimento do esmalte dentário) em pacientes pediátricos com asma e sua relação com a severidade da asma, o início dos sintomas e o tratamento medicamentoso. MÉTODOS: Os participantes do estudo eram residentes do município de Londrina (PR), com 5 a 15 anos, sendo 68 asmáticos e 68 controles. Foram levantados dados retrospectivos da história médica e de saúde bucal da população do estudo através de um questionário estruturado. Todos os participantes foram submetidos a um exame dental. Para a avaliação dos defeitos de desenvolvimento do esmalte dentário, utilizou-se o Índice DDE. RESULTADOS: Neste estudo, foi observado que 61 (89,7 por cento) dos 68 pacientes asmáticos apresentavam defeitos de desenvolvimento do esmalte dentário quando comparado à ocorrência em 26 (38,2 por cento) dos no grupo controle. Através da análise multivariada por regressão logística, foi observado que um paciente pediátrico com asma apresenta risco aumentado em 11 vezes para o aparecimento de defeitos de desenvolvimento do esmalte em dentes permanentes (OR = 11,88, p = 0,0001). Além disso, foi observado uma associação entre defeitos do esmalte dentário e maior severidade da asma (p = 0,0001) e início dos sintomas mais precoce (p = 0,0001). Não se observou associação entre o início do tratamento (p = 0,08) ou frequência de uso da medicação (p = 0,93) com o aparecimento de defeitos de desenvolvimento do esmalte dentário. CONCLUSÕES: Pacientes pediátricos com asma apresentam risco aumentado para a ocorrência de defeitos de desenvolvimento do esmalte dentário relacionado à severidade da asma e início dos sintomas e, portanto, necessitam de atenção odontológica prioritária.

Análisis genético, clínico y molecular de una familia afectada con una malformación del esmalte dental / Genetic, clinical and molecular analysis of a family affected by amelogenesis imperfecta

Background: Amelogenesis Imperfecta (AI) is a group of conditions where there is an abnormal formation of enamel in terms of quantity, structure and composition. AI is clinically and genetically heterogeneous, there are sex linked and autosomal versions, dominant and/or recessive, with phenotypes of hypoplastic, hypocalcified or hypomature enamel. Only recently, through clinical, genetic and molecular studies of affected families, phenotypic-genotypic correlations are being established in this group of anomalies. Aim: To carry out a genetic, clinical and molecular analysis of a Chilean family affected with an enamel malformation, which probably would correspond to Amelogenesis Imperfecta Dominant Autosomal (AIDA), of hypoplastic type, resulting from g.6395G>A mutation in the enamelin gene. Patients and Methods: A genealogical pattern was created for five generations. Five members of this family group were clinically examined, and four of them had a molecular analysis that consisted of the detection of a mutation in the enamelin gene using PCR. Results: In this family, the enamel malformation presents a dominant autosomal pattern of inheritance. The clinical examination of the group allowed a diagnosis of Amelogenesis Imperfecta, of the hypoplastic local type. However, the molecular analysis revealed that the members analyzed did not exhibit the g.6395G>A mutation reported for the enamelin gene (ENAM). Conclusions: The enamel phenotype in this family could be explained by the presence of one of four other mutations recently described in this or another gene, thereby supporting the findings of allelic heterogeneity reported in the literature.