Major gene and multifactorial inheritance of mandibular prognathism

Abstract

Mandibular prognathism typically shows familial aggregation. Various genetic models have been described and it is assumed to be a multifactorial and polygenic trait, with a threshold for expression. Our goal was to examine specific genetic models of the familial transmission of this trait. The study sample comprised of 2,562 individuals from 55 families. Complete family histories for each proband were ascertained and the affection status of relatives were confirmed by lateral cephalograms, photographs, and dental models. Pedigrees were drawn using PELICAN and complex segregation analysis was performed using POINTER. Parts of some pedigrees were excluded to create one founder pedigrees, so the total N was 2,050. Analysis showed more affected females than males (P = 0.030). The majority of the pedigrees suggest autosomal dominant inheritance. Incomplete penetrance was demonstrated by the ratio of affected/unaffected parents and siblings. The heritability of mandibular prognathism was estimated to be 0.316. We conclude that there is a major gene that influences the expression of mandibular prognathism with clear signs of Mendelian inheritance and a multifactorial component.

Craniofacial Morphology of Class III Malocclusion with DUSP6 Gene: Mutation and Non-Mutation Groups

“…The etiology of class III malocclusion is a curious issue and there is much to be clarified and understood. To describe class III malocclusion, environmental and genetic factors are playing the major role and it follows the autosomal dominant mode of inheritance was confirmed from altered studies 1,7,8) . However, the relationship concerning cranialbase morphology related to genetic heritability and Class III malocclusion is not entirely understood.…”

“…Such skeletal disparity is consequences from growth resentment between maxilla and mandible, therefore creating a concave facial profile. Class III craniofacial structure is a concern of the fact that many patients having this malocclusion are treated routinely with orthodontics 7) . The concern of development in class III subjects has become more important because of the increasing awareness in enhancing treatment timing and planning in dentofacial orthopedics.…”

Retrognathic maxilla in “Habsburg jaw”

“…Genetic analysis of families with the Class III phenotype supports the hypothesis of polygenic inheritance. [4][5][6][7] Recently, Cruz et al 8 in a study on 55 Brazilian families with mandibular prognathism concluded that there is a major gene that influences the expression of the trait with clear signs of Mendelian inheritance.…”

Segregation analysis of mandibular prognathism in Korean orthognathic surgery patients and their families

“…17 These investigations suggested that MP has an autosomal dominant inheritance with or without incomplete penetrance. Interestingly, although Yamaguchi et al 5 reported that three markers (D1S234, D6S1689, and D19S566) were associated with MP in Koreans/ Japanese, a follow-up study of Cruz et al 18 showed that these markers did not have any evidence of linkage in the Brazilian population.…”

“…Cruz et al 17 also performed a segregation analysis on 55 Brazilian families with 2562 relatives. Their study was similar to this study in terms of the subject number and the recruited subtype of Class III malocclusion a q_A indicates the frequency of the allele A in the population when Hardy-Weinberg equilibrium is assumed; t, transmission parameter (the probability that a parent transmits allele A to offspring); s 3 2 , the variance of the polygenic effect incorporating three polygenic loci.…”