Exploring the association between genetic and environmental factors and molar incisor hypomineralization: evidence from a twin study

Abstract

The greater concordance in the diagnosis of MIH among monozygotic twins indicates a genetic influence, although environmental factors, such as family income and hemorrhage during pregnancy, are also associated with the occurrence of MIH.

On the genetics contribution to molar incisor hypomineralization

“…The difference in concordance rates between monozygotic and dizygotic twins reported by Teixeira et al, 1 and the h 2 we calculated here strongly support a genetic component to MIH. It also shows that MIH is likely a gene-environmental model with multiple genes with small individual effect each and future studies aiming to understand mechanisms should be designed to consider genotypes and environmental risk factors in combination.…”

“…Dear Editor, The March 2018 issue of International Journal of Paediatric Dentistry brought the report "Exploring the Association between Genetic and Environmental Factors and Molar Incisor Hypomineralization: Evidence from a Twin Study" by Teixeira et al, 1 in which the authors evaluated the agreement of the occurrence of molar incisor hypomineralization (MIH) in monozygotic vs dizygotic twins. The authors found a greater concordance among monozygotic twins and concluded that a genetic contribution to MIH indeed exists.…”

On the Variable Clinical Presentation of Molar-Incisor Hypomineralization

“…This model fits very well with MIH from what is known from the literature regarding variation in frequency, depending on geographic origin [Vieira and Kup, 2016], variation in severity and clinical presentation [Vieira and Kup, 2016], and no clear aggregation in families for most of the cases, although approximately 20% of families have additional affected family members [Jeremias et al, 2016]. Twin studies indeed showed a higher concordance rate for monozygotic twins in comparison with dizygotic ones both in the classic presentation of MIH [Teixeira et al, 2018] and in hypomineralized second primary molars [Silva et al, 2019]. Based on the figures published by Teixeira et al [2018], we could calculate that the amount of MIH variation in the population that can be explained by genetics is approximately 20% [Vieira, 2019].…”

“…Twin studies indeed showed a higher concordance rate for monozygotic twins in comparison with dizygotic ones both in the classic presentation of MIH [Teixeira et al, 2018] and in hypomineralized second primary molars [Silva et al, 2019]. Based on the figures published by Teixeira et al [2018], we could calculate that the amount of MIH variation in the population that can be explained by genetics is approximately 20% [Vieira, 2019]. These later twin data leave no room for questioning a genetic contribution to MIH.…”

Genes Regulating Immune Response and Amelogenesis Interact in Increasing the Susceptibility to Molar-Incisor Hypomineralization

“…We utilized a logistic regression considering the genotype of each polymorphism and presence/absence of conditions previously cited by other studies as MIH covariates, or possible factors associated with MIH (preterm delivery, common childhood diseases high fever, pneumonia, and respiratory diseases) [Teixeira et al, 2018].…”