Associations between the risk of tooth agenesis and single-nucleotide polymorphisms of MSX1 and PAX9 genes in nonsyndromic cleft patients

Tooth Anomalies in Patients With Nonsyndromic Orofacial Cleft: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate the frequency of tooth anomalies (TA) in the deciduous and permanent dentition of patients with nonsyndromic orofacial clefts (NSOC), both inside and outside the cleft area.

METHODS

The following databases were searched for the relevant literature: Cochrane, OVID, SciELO, Embase, Livivo, PubMed, Scopus, and Web of Science. The risk of bias was analyzed using the Joanna Briggs Institute. Fixed and random-effects meta-analysis was performed comparing the presence and absence of NSOC subtypes. The certainty of evidence was evaluated using the GRADE approach.

RESULTS

Out of 1939 articles identified, after applying the inclusion and exclusion criteria, a total of 75 articles were included (46 cohort and 29 case-control), including 27,703 patients (16,450 with NSOC and 11,253 healthy controls) from 34 countries. The meta-analyses revealed higher odds for tooth agenesis (ORNSOC: 3.72; p = 0.001) and macrodontia (ORNSOC: 8.04; p = 0.04) across the different cleft subtypes outside the cleft area compared with the control group in the permanent dentition, whereas the frequency of root dilaceration was significantly lower in nonsyndromic cleft lip only (NSCLO) (ORNSCLO: 0.38; p < 0.0001) and in nonsyndromic cleft lip and palate (NSCLP) (ORNSCLP: 0.44; 95% p < 0.0001). The results also demonstrated a higher risk of tooth agenesis (ORNSOC: 16.49; p < 0.0001), microdontia (ORNSOC: 17.14; p < 0.0001), macrodontia (ORNSOC: 10.41; p = 0.02), supernumerary tooth (ORNSOC: 10.03; p < 0.0001), and enamel hypoplasia (ORNSOC: 5.62; p < 0.0001) in the permanent dentition inside the cleft area of patients with NSOC. However, for the deciduous dentition, outside the cleft area, microdontia was the only TA significantly more frequent in patients with NSOC (ORNSOC: 6.24; p = 0.006) and nonsyndromic cleft palate only (NSCPO) (ORNSCPO: 8.45; p = 0.02) compared with the control group. TA associations varied across populations. In Europe, no significant associations were found for NSOC, while in Asia, strong associations were observed for NSCLP and NSCL ± P (ORNSCLP and NSCL±P: 139.19; p < 0.0001). In South America, significant associations were identified for NSCLP (ORNSCLP: 2.16; p < 0.0001), NSCL ± P (ORNSCL±P: 2.48; p < 0.0001), and NSOC (ORNSOC: 2.72; p < 0.0001). In North America, tooth agenesis was more frequent in NSCL ± P (ORNSCL±P: 4.75; p < 0.0001), though no significant associations were found for NSCLP or NSOC. In the cleft area, significant associations were observed in European populations for NSOC, including increased frequencies of tooth agenesis (ORNSOC: 19.57; p = 0.003) and supernumerary teeth (ORNSOC: 9.77; p < 0.0001). Asian populations showed similar patterns (ORNSOC: 19.23; p = 0.002), while no significant associations were noted in South America due to limited data. Root dilaceration remained less frequent in NSCLO (ORNSCLO: 0.38; p < 0.0001) and NSCLP (ORNSCLP: 0.44; p < 0.0001), with no associations identified for microdontia, taurodontism, supernumerary tooth, impacted tooth, or transposition.

CONCLUSION

The results confirm a higher frequency of TA in the permanent dentition of patients with NSOC compared to controls, regardless of cleft subtype. However, significant differences were observed depending on whether the TA occurred inside or outside the cleft area. Although only a limited number of studies were included, microdontia was the only TA significantly more prevalent in the cleft area of patients with NSOC in the deciduous dentition. Variations in the frequency of TA across populations highlight the complex interplay of genetic, environmental, and methodological factors influencing these associations. Despite these findings, the quality of the existing evidence is moderate, with limitations stemming from small sample sizes, methodological variations, and study heterogeneity. These results emphasize the importance of tailored dental management and early intervention strategies for individuals with different cleft subtypes to effectively address and mitigate the impact of these tooth anomalies on oral health and development.

Genetic association between Class II division 1 and division 2 malocclusions with PAX9 (rs8004560) gene polymorphism in a tertiary care hospital

OBJECTIVE

To assess whether there is any difference in the genetic association between Class II division 1 (div. 1) and division 2 (div. 2) malocclusions using PAX9 (rs8004560) gene single nucleotide polymorphism (SNP).

MATERIAL AND METHODS

Sixty patients from the Orthodontics department of Subharti Dental College and Hospital (Meerut, India) were divided into two groups: Group 1 (Class II div. 1 malocclusion) and Group 2 (Class II div. 2 malocclusion). Then, 3 mL of blood was collected from each participant. DNA extraction was done, and Sanger Sequencing was performed from extracted DNA samples.

RESULTS

A statistically significant difference was found in the distribution of alleles among Class II div. 1 and Class II div. 2 malocclusions. The homozygous GG allele was the most prevalent among Class II div. 1 patients (76.7%), while the heterozygous AG allele was the most prevalent among Class II div. 2 patients (53.5%). Since GG was the most prevalent allele, it was used as a reference, and AA/AG were compared with GG to confirm the association. The results showed that individuals with the AG genotype seemed to be more susceptible to the development of skeletal Class II div. 2 malocclusion.

CONCLUSION

The homozygous GG allele was the most prevalent among Class II div. 1 patients, while the heterozygous AG allele was the most prevalent among Class II div. 2 patients, suggesting that there could be a difference between the genetic association of both malocclusions.

Correlation of Dental Anomalies with Cleft Type and Gender in Non-Syndromic Oral Cleft Patients: A Cross-Sectional Study

To investigate the distribution of dental anomalies between non-syndromic orofacial cleft patients and their association with the cleft type and gender.

Retrospective cross-sectional study involving examination of intraoral dental records and radiographs.

300 non-syndromic orofacial cleft patients included (161 males and 139 females, mean age: 10.23 ± 2.3 years).

Variables analyzed: tooth agenesis, microdontia, and supernumerary teeth. Data analysis: Chi-square and Fisher's exact tests to investigate the correlation between dental anomalies, cleft type, and gender.

Agenesis occurred in 66% of the subjects, supernumerary teeth in 19.6%, and microdontia in 18.3%. In females with unilateral left cleft lip and palate (CLP), agenesis was significantly higher compared to males. Both genders presented significant agenesis of maxillary lateral incisors and right central incisor. Significant agenesis of central incisor, canine and second premolar on the upper left side and lower second premolars were observed only in males, with significant microdontia for maxillary lateral incisors and left central incisor. Significant agenesis of maxillary first premolars was seen only in females. Agenesis in maxillary quadrants was significant for patients with unilateral right and left CLP, and bilateral CLP. In mandibular quadrants, agenesis was substantially higher for patients with isolated CP.

Results suggest that tooth agenesis and microdontia might not be directly associated with the cleft area's anatomical irregularity but are affected by gender and other genetic factors that regulate the development of the anomaly and the orofacial clefting mutually.

Dental anomalies in cleft lip and/or palate children at age 10 - a retrospective review across three cleft centres: Part 1

Introduction Children with oral clefts often present with dental anomalies which can impact function, aesthetics and complicate the patient's dental treatment and needs. An understanding of potential anomalies, along with early recognition and planning, is thus essential for effective care.Aim This paper is the first in a two-part three-centre series. This paper will assess the dental anomalies identified in 10-year-old patients attending three cleft centres in the UK.Method Retrospective review was undertaken of the clinical notes of 10-year-old patients attending South Wales (SW), Cleft NET East (CNE) and West Midlands (WM) cleft units, for their ten-year audit record appointment in 2016/2017.Results In total, 144 patients were reviewed (SW = 42; CNE = 52; WM = 50). Dental anomalies were recorded for 80.6% of patients (n = 116).Discussion The review gives insight into the dental complexities of UK oral cleft patients. These patients require specialist paediatric dental input and intensive preventive regimes.Conclusion Shared care between cleft team specialists and general dental practitioners is important when providing holistic care for cleft patients.

Tooth abnormalities associated with non-syndromic cleft lip and palate: systematic review and meta-analysis

OBJECTIVE

To evaluate the association between orofacial clefts (OFC) and tooth abnormalities (TA).

METHODS

We searched PubMed, Scopus, Web of Science, Cochrane Library, LILACS, and BBO, and in the gray literature and selected observational studies that evaluated the association between TA and OFC. The risk of bias was analyzed using the Newcastle-Ottawa Scale. A random-effects meta-analysis was performed comparing the presence and absence of OFC, cleft type-cleft palate (CP) and cleft lip with or without palate (CL/P)-and cleft laterality-unilateral and bilateral. The certainty of evidence was evaluated using the GRADE approach.

RESULTS

A total of 99 studies were included in the qualitative analysis, and 37 were included in the meta-analysis. Only four studies were classified as low risk of bias. Significant associations were observed between the presence of OFC and tooth agenesis (OR = 19.46; 95%CI = 4.99-75.96), supernumerary teeth (OR = 4.04; 95%CI = 1.26-12.99), developmental defects of enamel (OR = 3.15; 95%CI = 1.28-7.80), microdontia (OR = 15.57; 95%CI = 1.06-228.51), and taurodontism (OR = 1.74; 95%CI = 1.74-2.86). Individuals with CP had a lower frequency of supernumerary teeth (OR = 0.22; 95%CI = 0.08-0.64), peg-shaped tooth (OR = 0.31; 95%CI = 0.12-0.80), and morphological TA (OR = 0.13; 95%CI = 0.04-0.45) than individuals with CL/P. No TA was significantly associated with cleft laterality (p > 0.05). The quality of the evidence was very low in all analyses.

CONCLUSION

Individuals with OFC had a higher frequency of TA than those without OFC. Individuals with CP had a lower frequency of TA than individuals with CL/P. No TA was associated to cleft laterality.

CLINICAL RELEVANCE

Help to identify the treatment needs of individuals affected by OFC, improving the services provided to this population.

Subphenotypes in Non-Syndromic Orofacial Cleft Patients Based on the Tooth Agenesis Code (TAC)

Background: It was the aim of this study to investigate tooth agenesis patterns, which are expressed to different subphenotypes according to the TAC method in a spectrum of non-syndromic orofacial cleft patients. Methods: A total of 183 orofacial cleft patient records were assessed for tooth agenesis and TAC patterns. The association between TAC and sex, and cleft type was examined, and logistic regression models were additionally applied. Additionally, the distribution of missing teeth by cleft type and the tooth agenesis inter-quadrant association were examined. Results: The most frequent cleft type was CLPL (n = 72; 39.3%), while the maxillary left lateral incisor was the most frequently missing tooth that was strongly dependent on the cleft type (29.5%, p < 0.001). Of the 31 TAC patterns identified, four were the most prevalent and occurred in 80.8% of the sample, while 20 TAC patterns were unique. Cleft type contrary to sex (p = 0.405) was found to play a significant role in TAC distribution (p = 0.001). The logistic regression’s results suggested that overall, neither sex nor cleft type were associated with tooth agenesis. Prevalence of tooth agenesis in each quadrant clearly depended on cleft type; and there was a strong association found between tooth agenesis in different quadrants. Conclusions: Thirty-one different subphenotypes were identified in TAC patterns. The first four TAC patterns accounted for the 80.8% of the sample’s variability while twenty of the patterns were unique. A strong association was present between TAC pattern and cleft type. No association was found between the sex of the patient, tooth agenesis and TAC patterns. Tooth agenesis depended strongly on the cleft type, and the most frequently missing tooth was the maxillary left lateral incisor. The interquadrant association for tooth agenesis found suggests a genetic link in the etiology of clefts.

Scandcleft randomized trials of primary surgery for unilateral cleft lip and palate: impact of maxillary dental agenesis on craniofacial growth and dental arch relationship in 8 year olds

BACKGROUND

It is suggested that dental agenesis affects maxillary protrusion and dental arch relationship in children with unilateral cleft lip and palate (UCLP). In addition, an association between the need for orthognathic surgery and dental agenesis is reported.

AIM

The aim was to study the impact of maxillary dental agenesis on craniofacial growth and dental arch relationship in 8-year-old children with UCLP.

SUBJECTS AND METHODS

The sample consisted of individuals with UCLP from Scandcleft randomized trials. The participants had available data from diagnosis of maxillary dental agenesis as well as cephalometric measurements (n = 399) and GOSLON assessment (n = 408) at 8 years of age.

RESULTS

A statistically significant difference was found for ANB between individuals with agenesis of two or more maxillary teeth (mean 1.52°) in comparison with those with no or only one missing maxillary tooth (mean 3.30° and 2.70°, respectively). Mean NSL/NL was lower among individuals with agenesis of two or more maxillary teeth (mean 9.90°), in comparison with individuals with no or one missing maxillary tooth (mean 11.46° and 11.45°, respectively). The number of individuals with GOSLON score 4-5 was 47.2% in the group with two or more missing maxillary teeth and 26.1% respectively 26.3% in the groups with no or one missing maxillary tooth. No statistically significant difference was found in the comparison between individuals with no agenesis or with agenesis solely of the cleft-side lateral.

CONCLUSION

Maxillary dental agenesis impacts on craniofacial growth as well as dental arch relationship and should be considered in orthodontic treatment planning.

Frequency of Additional Congenital Dental Anomalies in Children with Cleft Lip, Alveolar and Palate

The aim of the study was to assess the risk of incidence of additional congenital dental anomalies in children with nonsyndromic cleft lip, alveolar and/without palate (CL/P). Hypodontia, hyperdontia and canines impaction was recognized. From patients with CL/P treated at the Clinic of Congenital Facial Deformities in Chair and Department of Jaw Orthopedics Medical University of Lublin, 56 subjects were randomly selected. On the panoramic radiographs taken at the age of 8-12 years, the angle of upper unerupted canines was measured using Westerlund's recommendations. The supernumerary teeth and hypodontia were checked. The procedures: maxillary expansion, secondary alveolar bone graft (SABG) and extraction of primary canines were noted. The frequency of canines impaction was 5.36%. Hypodontia was found in 37.5% of patients; hyperdontia was present in 23.21% of patients. No influence of procedures (expansion of the maxilla, SABG, deciduous canines extraction) on permanent maxillary canine eruption was proved. Patients with CL/P are exposed to the unfavorable position of unerupted maxillary canines most frequently in the cleft area of complete cleft. Maxillary lateral incisor on the cleft side is most frequently affected with congenital anomaly. Hypodontia and hyperdontia do not influence maxillary canine impaction. Good clinical result was achieved with an applied approach, which should be widely introduced.

Association between Dental Anomalies and Orofacial Clefts: A Meta-analysis

OBJECTIVES

To conduct a systematic review and meta-analysis to assess whether individuals with nonsyndromic orofacial clefts (OCs) display a higher frequency of dental anomalies (DAs) when compared with individuals without OCs.

METHODS

A literature search of indexed databases (PubMed, Cochrane, Web of Science, Embase, Scopus, and LILACS) was conducted without language restriction up to and including February 1, 2020. Cross-referencing was used to further identify articles. Several cleft teams across the United States and Europe were contacted to obtain unpublished data. The eligibility criteria were observational studies with original data that statistically compared individuals with OC without syndromes and those without OC on any type of DA in primary and/or permanent dentition. Random effects meta-analysis through the Mantel-Haenszel estimator was used to evaluate the association between OC and DA based on odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

The literature search generated 933 records, and 75 full-text articles were reviewed. Twenty-six studies encompassing 15,213 individuals met the inclusion criteria. The meta-analysis revealed statistically significant associations between OC and agenesis (OR, 14.2; 95% CI, 9.4 to 21.3), supernumerary teeth (OR, 5.7; 95% CI, 3.3 to 9.7), developmental enamel defects (OR, 5.6; 95% CI, 3.5 to 9.0), microdontia (OR, 14.8; 95% CI, 4.0 to 54.6), peg-shaped anterior teeth (OR, 12.2; 95% CI, 3.6 to 41.2), taurodontism (OR, 1.7; 95% CI, 1.0 to 2.7), tooth malposition and/or transposition (OR, 5.6; 95% CI, 2.8 to 11.5), tooth rotation (OR, 3.2; 95% CI, 1.3 to 8.2), and tooth impaction (OR, 3.6; 95% CI, 1.1 to 12.2). The OR estimates of the reviewed studies exhibited significant heterogeneity (P < 0.0001). No association was observed between OC and fusion and/or gemination.

CONCLUSION

Within the limitations of this study, the available evidence suggests that individuals with OCs are more likely to present with a range of DAs than their unaffected peers.

KNOWLEDGE TRANSFER STATEMENT

The findings of the current review suggest that individuals with orofacial clefts (OCs) are more likely to present with a range of dental anomalies than their unaffected peers. Understanding the association between OCs and dental anomalies is essential in guiding clinicians during treatment-planning procedures and is important in raising our awareness of the possible need for future dental treatment for patients with OCs.

Dental development in patients with and without unilateral cleft lip and palate (UCLP): a case control study

OBJECTIVE

To evaluate if the presence of unilateral cleft lip and palate (UCLP) causes delay in dental age and tooth development.

MATERIALS AND METHODS

Panoramic radiographs of 189 non-syndromic UCLP patients, aged from 6 to 20 years, were collected. Two measures of tooth development were examined: dental maturity scale for the seven left mandibular teeth (dental age-DA) and the degree of each tooth development (developmental score-DS). All the teeth except third molars were staged according to the Demirjian's method. The data of the cleft group were compared with a control group matched for age and gender, based on the findings observed in other 189 panoramic radiographs.

RESULTS

At all ages, DA was lower in the UCLP group, but not always significantly; the highest difference was - 1.411 for females at 13 years old and - 0.776 for males at 12 years old. DS of all teeth was significantly lower in the UCLP group, at all ages under 17 in females, and at all ages under 18 in males. In UCLP group, tooth development was more delayed in the maxilla compared with the mandible. No evidence of a slower development at the cleft side compared with the non-cleft side was highlighted.

CONCLUSIONS

Significant lower dental development was observed in UCLP patients compared with control ones by using DS and DA indexes.

CLINICAL RELEVANCE

These findings can help the clinicians in establishing a proper orthodontic and surgical diagnosis and treatment planning in UCLP patients and for forensic age estimation's purposes.

Genetic variants in tooth agenesis-related genes might be also involved in tooth size variations

OBJECTIVE

The present study aimed to evaluate if genetic variants in PAX9, MSX1, TGFα, FGF3, FGF10, FGF13, GLI2 and GLI3 are involved in TS of permanent teeth.

MATERIALS AND METHODS

Pretreatment dental records from orthodontic patients were assessed prior to recruitment. Patients with tooth agenesis and congenital anomalies (including oral cleft) and/or syndromes were excluded. Dental casts were used to measure the maximum crown dimensions of all fully erupted permanent teeth except second and third molars in mesiodistal direction. Teeth with caries, occlusal wear, mesiodistal restorations, and obvious deformities were not evaluated. Genomic DNA samples were used for genotyping. The allelic discrimination of 13 genetic variants was performed. The associations between TS and genotype were analyzed by linear regression, adjusted by gender at a significance level of p ≤ 0.05.

RESULTS

Genetic polymorphisms in the tooth agenesis-related genes studied here were associated with increased and decreased TS, in both maxilla and mandible (p < 0.05).

CONCLUSION

This study reported associations of novel tooth agenesis-related gene variants with permanent tooth size variations.

CLINICAL RELEVANCE

The presence of some genetic variants could allow the prediction of permanent tooth size.

Scandcleft randomized trials of primary surgery for unilateral cleft lip and palate: dental anomalies in 8-year olds

BACKGROUND

Children born with unilateral cleft lip and palate (UCLP) are reported to display several dental anomalies including agenesis, supernumeraries, as well as variations in dental size, shape, and path of eruption. The extensive sample of individuals with UCLP included in the Scandcleft randomized control trials offers the opportunity to study more rare conditions, which is seldom possible with limited samples.

OBJECTIVES

The aim was to study dental anomalies at 8 years of age in children born with UCLP included in the Scandcleft randomized control trials.

METHODS

Panoramic and intraoral radiographs from 425 individuals (279 males and 146 females) with a mean age of 8.1 years were assessed by four orthodontists regarding dental anomalies.

RESULTS

Agenesis was found in 52.5 per cent and supernumerary teeth in 16.9 per cent of the participants. The cleft lateral was missing in 43.8 per cent and was found peg shaped in 44.7 per cent. The distribution of ectopic eruption was 14.6 per cent, mainly affecting maxillary first molars, while transposition was found in 3.4 per cent of the individuals. In addition, infraocclusion of one or several primary molars was registered in 7.2 per cent of the participants.

CONCLUSION

We conclude that 8-year-old children born with UCLP display multiple dental anomalies. The Scandcleft sample allowed rarely studied conditions such as infraocclusion of primary molars and transposition to be studied in children born with UCLP.

TRIAL REGISTRATION

ISRCTN29932826.

Association between MSX1 rs12532 polymorphism with nonsyndromic unilateral complete cleft lip and palate and tooth agenesis

OBJECTIVES

To investigate the association of MSX1 rs12532 polymorphism with the risk of nonsyndromic unilateral complete cleft lip and palate (NSCLP) and tooth agenesis.

MATERIALS AND METHODS

The study is comprised of 384 individuals divided into 4 groups: group 1, patients with unilateral complete NSCLP and premolar agenesis (n = 57); group 2, patients with unilateral NSCLP without tooth agenesis (n = 117); group 3, patients with premolar agenesis without oral cleft (n = 53) and group 4 (n = 157), a control group with individuals without tooth agenesis and oral cleft. Genotyping of rs12532 was carried out with Taqman chemistry, and associations were investigated using logistic regression analyses.

RESULTS

Overall rs12532 allele and genotype distributions revealed no significant differences between the groups of NSCLP or tooth agenesis.

CONCLUSION

Although our results are consistent with a lack of association of MSX1 rs12532 and the risk of unilateral NSCLP and tooth agenesis, further studies with additional SNPs and a more diverse ethnic cohort are warranted.

Dental Anomalies in Permanent Teeth Associated With Nonsyndromic Cleft Lip and Palate in a Group of Colombian Children

Objectives:

To assess the risk of dental anomaly presentation in permanent teeth in a group of Colombian children with nonsyndromic cleft lip and palate (NSCLP) and to determine the frequency of the anomalies according to the cleft type.

Methods:

An analytical matched case–control study was conducted with 210 controls and 210 patients with NSCLP. The patients were classified into 3 groups: complete right unilateral cleft lip and palate (RCLP), complete left unilateral cleft lip and palate (LCLP), and complete bilateral cleft lip and palate (BCLP). Univariate and multivariate Poisson regression models were used to analyze paired samples (Bonferroni adjustment, P ≤ .002).

Results:

A high risk of finding agenesis of the maxillary lateral incisors, supernumerary teeth, microdontia of the maxillary lateral incisors, and rotation of the maxillary central incisors adjacent to the cleft ( P < .0001) was observed in the patients with NSCLP. One or more dental anomalies were found in 98% of patients with BCLP, in 96% of those with LCLP, and in 87% of those with RCLP. Most of the anomalies were located on the cleft area. The incidence relative risk (IRR) of anomalies was highest in patients with BCLP (IRR: 10.5; 95% confidence interval [CI]: 6.76-16.3), followed by in those with LCLP (IRR: 8.51; 95% CI: 5.64-12.8).

Conclusions:

Most dental anomalies were found in the cleft area; this was expected because the cleft area was the most affected in the patients included in this study.

MSX1 gene polymorphisms and non-syndromic cleft lip with or without palate (NSCL/P): A meta-analysis

OBJECTIVE

Non-syndromic cleft lip, with or without cleft palate (NSCL/P), is a common craniofacial birth defect, the risk of which is influenced from multiple genetic loci. Association study outcomes between single nucleotide polymorphisms (SNPs) near the muscle segment homeobox gene 1 (MSX1) and NSCL/P have been inconsistent. This compels a meta-analysis to obtain more precise estimates.

METHODS

From 15 publications, we examined 12 SNPs under six groups (SG), based on linkage disequilibrium. Pooled odds ratios and 95% confidence intervals were calculated under the standard genetic models. The pooled effects were subjected to subgroup, outlier, sensitivity, and funnel plot (publication bias) analyses.

RESULTS

Three of the six SGs showed significant associations. SG1 and SG4 effects indicated reduced risks. SG1 outcomes were attributed to outlier treatment, which the Asian outcomes validated. In contrast, increased risks were observed in SG3. All these significant outcomes were deemed robust by sensitivity analysis with no evidence of publication bias.

CONCLUSIONS

Our study shows eight MSX1 SNPs associated with risk of NSCL/P. SG1 and SG4 carriers are protected (up to 23%), but SG3 carriers are 1.3-fold susceptible. Outlier treatment unmasked the significant associations in SG1. Non-heterogeneity and robustness helped elevate the level of evidence in our significant findings.

Non-syndromic cleft lip with or without palate susceptible loci is associated with tooth agenesis

OBJECTIVE

Non-syndromic tooth agenesis (NSTA) may share common genetic factors with non-syndromic cleft lip with or without cleft palate (NSCL/P). Single-nucleotide polymorphisms (SNPs) were associated with individual's susceptibility to these anomalies. We selected five NSCL/P-associated SNPs from our previous genome-wide association study (GWAS) to test for the associations with NSTA.

MATERIALS AND METHODS

A total of 677 NSTA cases and 1,144 healthy controls were recruited in this case-control study. Five genome-wide NSCL/P-associated SNPs (rs2235371, rs7078160, rs8049367, rs4791774, and rs13041247) were genotyped by TaqMan platform and evaluated for the associations with NSTA using plink software.

RESULTS

No significant associations between these SNPs and risk of NSTA were observed in the overall analysis and subgroup analysis with the number of missing teeth. However, in the subgroup analysis by tooth position, rs8049367 was nominally associated with mandibular premolar agenesis (Dominant model: OR_dom  = 0.66, 95% CI_dom  = 0.47-0.93, p_dom  = 0.016; Heterozygote model: OR_het  = 0.60, 95% CI_het  = 0.41-0.88, P_het  = 0.008). Rs4791774 showed a nominal association with congenitally missing maxillary canine (Dominant model: OR_dom  = 0.53, 95% CI_dom  = 0.28-0.98, p_dom  = 0.041; Heterozygote model: OR_het  = 0.50, 95% CI_het  = 0.26-0.97, P_het  = 0.041) and premolar (Additive model: OR = 0.59, 95% CI = 0.36-0.96, p = 0.035).

CONCLUSION

This study showed that NSCL/P susceptible loci rs8049367 and rs4791774 were probably associated with the risk of NSTA.

Nonsyndromic cleft lip and/or palate: A multicenter study of the dental anomalies involved

Background

Nonsyndromic cleft lip and/or palate (NSCL/P) is the most common craniofacial malformation. Due to the anatomical defect present in the alveolar process, these patients tend to exhibit more dental anomalies. The aim of this study was to identify the prevalence of dental anomalies in patients with NSCL/P by obtaining orthodontic documentation from Brazilian Centers for cleft lip and palate treatment.

Material and Methods

A retrospective analysis (2000-2014) was conducted on orthodontic archives, radiographs and medical records of NSCL/P of 524 patients under orthodontic treatment. Panoramic radiographs and intra-oral photographs were examined to identify these anomalies. Categorical variables were expressed in terms of frequencies and percentages and analyzed using the Chi-Square test. The level of significance was set at p≤0.05 in all analyses.

Results

Approximately 83.3% of the individuals had at least one dental anomaly. Tooth agenesis was the most common abnormality found in those patients (87.8%) (p<0.001). Also, the largest number of dental anomalies was detected in the group of unilateral left clefts. The prevalence of dental anomalies in the present sample of NSCL/P patients was high and reached the highest levels in patients with alveolar bone clefts.

Conclusions

This study describes the most common dental anomalies observed in patients with NSCL/P. These abnormalities can cause significant problems that may be solved or minimized by early diagnosis and treatment.

Key words:Cleft lip and/or palate, dental care for children, epidemiology, craniofacial abnormalities.

Tooth agenesis and orofacial clefting: genetic brothers in arms?

Tooth agenesis and orofacial clefts represent the most common developmental anomalies and their co-occurrence is often reported in patients as well in animal models. The aim of the present systematic review is to thoroughly investigate the current literature (PubMed, EMBASE) to identify the genes and genomic loci contributing to syndromic or non-syndromic co-occurrence of tooth agenesis and orofacial clefts, to gain insight into the molecular mechanisms underlying their dual involvement in the development of teeth and facial primordia. Altogether, 84 articles including phenotype and genotype description provided 9 genomic loci and 26 gene candidates underlying the co-occurrence of the two congenital defects: MSX1, PAX9, IRF6, TP63, KMT2D, KDM6A, SATB2, TBX22, TGFα, TGFβ3, TGFβR1, TGFβR2, FGF8, FGFR1, KISS1R, WNT3, WNT5A, CDH1, CHD7, AXIN2, TWIST1, BCOR, OFD1, PTCH1, PITX2, and PVRL1. The molecular pathways, cellular functions, tissue-specific expression and disease association were investigated using publicly accessible databases (EntrezGene, UniProt, OMIM). The Gene Ontology terms of the biological processes mediated by the candidate genes were used to cluster them using the GOTermMapper (Lewis-Sigler Institute, Princeton University), speculating on six super-clusters: (a) anatomical development, (b) cell division, growth and motility, (c) cell metabolism and catabolism, (d) cell transport, (e) cell structure organization and (f) organ/system-specific processes. This review aims to increase the knowledge on the mechanisms underlying the co-occurrence of tooth agenesis and orofacial clefts, to pave the way for improving targeted (prenatal) molecular diagnosis and finally to reflect on therapeutic or ultimately preventive strategies for these disabling conditions in the future.

WITHDRAWN: The MSX1 gene polymorphisms rs12532 and rs1001179 confer an increased risk of non syndromic orofacial clefts

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A miRNA-binding-site SNP of MSX1 is Associated with NSOC Susceptibility

MSX1 is a favorable candidate gene for susceptibility to non-syndromic orofacial clefts (NSOCs). However, the roles of MSX1 genetic variants in the development of NSOC are controversial and vary among human populations. In the present study, the roles of 4 potentially functional single-nucleotide polymorphisms (SNPs) of MSX1 (rs12532 in 3′-untranslated region [UTR], and rs3821947, rs3821949, and rs4464513 in 5′ upstream) were investigated in a case-control study of 602 NSOC cases and 605 healthy controls. The findings showed that rs12532 located within 3′-UTR of MSX1 could influence the risk of developing NSOC. Individuals who carried the variant genotype (rs12532AA genotype) showed a decreased possibility of developing NSOC (AA vs. GG: OR = 0.69, 95% CI = [0.49, 0.98]). Interestingly, similar effects were also observed on cleft lip with palate (CLP), in a stratified analysis (allelic comparison-12532A allele vs. 12532G allele, OR = 0.80, 95% CI = [0.66, 0.99]; genotypic comparison-AA vs. GG, OR = 0.58 95% CI = [0.37, 0.91]). Sequence analysis indicated that this SNP might alter the binding ability of miR-3649, confirmed by luciferase activity assay showing a lower expression level of rs12532 A allele compared with that of the G allele ( p < .001 for 293A and COS7 cell lines). Furthermore, an in vivo study showed that MSX1 expression among individuals carrying the AA genotype of rs12532 was markedly lower than that in those with the GG genotype, while the inverse correlation was observed for miR-3649, thus providing a possible interaction between MSX1 and miR-3649 in the etiology of NSOC. Taken together, these findings indicate that SNPs in the miRNA-binding sites might play an important role in the development of NSOCs. Furthermore, if confirmed in subsequent studies, the polymorphisms may be considered as additional markers for the evaluation of infants’ risk of NSOCs.