IRF6 and FGF1 polymorphisms in non-syndromic cleft lip with or without cleft palate in the Polish population

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is the most common developmental defect that significantly affects the morphology and function of the stomatognathic system in children. The etiology of these birth defects is multifactorial, and single nucleotide polymorphisms (SNPs) in IRF6 and FGF1 have been associated with NSCL/P. This study aimed to evaluate whether SNPs in IRF6, namely rs2013162, rs642961, rs2235373, and rs34010 in FGF1, are associated with NSCL/P occurrence in the Polish population. The study included 627 participants: 209 children with NSCL/P and 418 healthy controls. DNA was isolated from saliva in the study group and from umbilical cord blood in controls. Genotyping of polymorphisms was performed using quantitative PCR. There was no statistically significant association of IRF6 gene variants with NSCL/P occurrence, although for rs2013162, AA genotype, odds ratio (OR) = 1.16 and for AC genotype, OR = 0.83; for rs642961, AA genotype, OR = 0.84 and for AG genotype, OR = 1.41; and for rs2235373, AA genotype, OR = 0.79 and for AG, OR = 0.85. In the instance of rs34010 polymorphism in FGF1, the presence of the AA genotype was statistically significant in reducing the risk of NSCL/P (OR = 0.31, p = 0.001). Genetic variation in FGF1 is an important risk marker of NSCL/P in the Polish population, which cannot be stated for the polymorphisms in the IRF6 gene.

Palatal rugae morphology is associated with variation in tooth number

This observational study compared palatal rugae morphology in adolescent subjects with normal tooth number and tooth agenesis. Maxillary dental study casts were used to compare rugae number, length and shape. Each study group contained 60 subjects (30 females and 30 males) mean age 13.4 (SD, 1.55) in control and 13.56 (SD, 1.54) years in tooth agenesis groups (p = 0.576). Mean number of missing tooth units in the tooth agenesis group was 2.1. Mean number of primary rugae in the whole sample was 4.35 (SD, 0.98) on the right and 4.33 (SD, 0.92) on the left with no significant differences (p = 0.236 and p = 0.404, respectively). However, the number of secondary rugae on the left (p = 0.006) and fragmentary rugae on the right (p = 0.004) was significantly increased in the tooth agenesis group. The shape of left primary rugae 2 and 3 also differed between groups, tending towards a wavy pattern in the control group and curved in the tooth agenesis group (p = 0.012 and p = 0.004, respectively). In addition, primary rugae 3 was more convergent (p = 0.008) whilst left primary rugae 3 and 5 were orientated in an antero-posterior direction (p = 0.04 for both rugae) in the tooth agenesis group. Subgroup analysis also identified significant associations between patterns of tooth agenesis and rugae number, in addition to shape of primary rugae. The identification of significant differences in rugae pattern between subjects with normal tooth number and agenesis suggests potential commonality in signal pathway disruption during establishment of these structures.

Left-right asymmetry in palatal rugae is associated with genetic variants in WNT signaling pathway

OBJECTIVE

The present study evaluated the association between genetic variants in WNT3A and WNT11, and palatal rugae phenotypes.

DESIGN

Eighty-five biological unrelated orthodontic patients were included. Dental casts were assessed and data regarding the length, shape, direction and unification of rugae were recorded. The individuals were subsequently classified for each of the following rugae traits: total amount of rugae; bilateral symmetry in the amount, length and shape of the rugae; presence of secondary or fragmentary rugae; presence of unifications; predominant shape; and, direction of the rugae. Genetic variants in WNT3A (rs708111) and WNT11 (rs1533767) were genotyped by real-time PCR. Genotype and allele distributions were compared with an established alpha of 5 %.

RESULTS

The wavy and curve rugae were the most common. Genotype/phenotype analyses identified that the presence of the rs708111 A allele (OR = 2.2, 95 % CI: 1.1-4.4, p = 0.01) and the rs1533767 G allele (OR = 2.3, 95 % CI: 1.0-5.3, p = 0.05) increased in more than two times the chance of having bilateral asymmetry in the amount of the rugae. In the recessive model, individuals carrying two risk alleles (AA) of WNT3A rs708111 had a higher risk of presenting this phenotype. SNP-SNP interaction analysis revealed that individuals carrying one rs708111 A allele and rs1533767 G allele showed even a higher chance of having bilateral asymmetry in the amount of rugae (OR = 5.6, 95 % CI: 1.1-28.8, p = 0.03). No associations were identified for other rugae phenotype (p > 0.05).

CONCLUSION

Genetic variants in WNT3A and WNT11 were associated with the left-right asymmetry in the amount of palatal rugae.

The association between palatal rugae pattern and dental malocclusion

Introduction:

Palatal rugae complete its development during early intrauterine life, whereas dental malocclusions in permanent dentition establishes several years into the post-natal life.

Objective:

The objective of present study was to determine if there is an association between the palatal rugae pattern and Angle’s classes of malocclusion.

Methods:

A cross-sectional study was conducted on pretreatment dental casts of 184 patients. The sample was divided into the following groups: Class I, Class II div. 1, Class II div. 2, and Class III. The number of palatal rugae was recorded, bilaterally. The length, pattern and orientation of three anterior-most primary rugae on both sides were recorded.

Results:

The mean age of the study sample was 17.8 ± 5.4 years. The mean number of the palatal rugae was 11.18 ± 2.5, with significant differences among different malocclusion groups. The length of the first rugae on left side and third rugae on both sides varied significantly among the groups (p< 0.05). Similarly, the pattern of palatal rugae was also found to be significantly different among the malocclusion groups. The right sided rugae did not have any significant difference in the orientation in different malocclusion groups; however, the left sided rugae showed significant differences among the four malocclusion groups (p< 0.001).

Conclusions:

The current study showed subtle differences in the palatal rugae pattern among the Angle’s classes of malocclusion. Similarly, the length and orientation of some rugae were also found to be significantly different between malocclusion groups.

Alteration of palatine ruga pattern in subjects with oligodontia: A pilot study

INTRODUCTION

The aim of this study was to compare the palatal ruga patterns in subjects with oligodontia and normal tooth numbers.

METHODS

An observational investigation was conducted by using maxillary dental study casts to compare ruga numbers, lengths, and shapes in subjects with diagnosed oligodontia or normal tooth numbers.

RESULTS

A total of 32 subjects comprised both the oligodontia (mean age, 14.0 years; SD, 5.0 years) and the control (mean age, 14.5 years; SD, 5.1 years) groups. The mean number of missing teeth in the oligodontia group was 8.7. The mean number of rugae in the whole sample was 7.36 (SD, 1.16), with no significant difference between the groups (P = 0.264). For ruga pattern, no differences were found for right-sided rugae; however, on the left side, a significant difference existed in shape frequency associated with ruga 2. Specifically, a curved shape was seen more frequently in ruga 2 of the oligodontia group (P = 0.01).

CONCLUSIONS

The identification of subtle differences in ruga patterns between subjects with oligodontia and normal tooth numbers suggests potentially shared pathways during the development of these oral structures. Further large-scale investigations are warranted.