Orofacial Clefts: A Compendium on Non-Syndromic Cleft Lip-Cleft Palate

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.

Ethnic Differences in the Brazilian Population Influence the Impact of BMP4 Genetic Variants on Susceptibility of Nonsyndromic Orofacial Clefts

OBJECTIVE

The study evaluated the association of BMP4 tag-SNPs and SNP-SNP interactions involving genes active by BMP4 pathway during craniofacial development in the susceptibility of nonsyndromic orofacial clefts (NSOC) in the Brazilian population.

DESIGN

Case-control study.

SETTING

Brazilian Oral Cleft Group.

PARTICIPANTS

The study included 881 healthy controls and 800 patients with different types of NSOC: 232 with cleft lip only (NSCLO), 568 with cleft lip and palate (NSCLP), and 274 with cleft palate only (NSCPO).

INTERVENTIONS

The genomic DNA was genotyped with allelic discrimination assays for five BMP4 tag-SNPs (rs11623717, rs17563, rs2071047, rs2761887 and rs4898820), and analyzed their allelic and genotypic associations using multiple logistic regression. The interactions of these variants with genes involved in the BMP4 signaling pathway, including FGFR1, GREM1, NOG, VAX1 and the 4p16.2 locus, were explored.

MAIN OUTCOME MEASURES

BMP4 variants in the NSOC risk.

RESULTS

Although only nominal p values were identified when the whole sample was considered, subgroup analysis including the patients with high African genomic ancestry showed significant associations of rs2761887 with risk for nonsyndromic cleft lip with or without cleft palate (NSCL  ±  P)[(ORhom: 2.16; 95% CI: 1.21-3.85; p  =  0.01) and (ORrec: 2.05; 95% CI: 1.21-3.47; p  =  0.006)]. Thirteen significant SNP-SNP interactions involving BMP4 and the SNPs at FGFR1, GREM1, NOG and VAX1 and at locus 4p16.2 for increased risk of NSCL  ±  P were identified.

CONCLUSIONS

Our results demonstrate an increased risk of NSCL  ±  P in Brazilian individuals with enrichment of African ancestry in the presence of the BMP4 rs2762887 polymorphism, and reveal relevant genetic contribution of SNP-SNP epistatic interactions involving BMP4 variants to NSCL  ±  P risk.

Exploring the role of the WNT5A rs566926 polymorphism and its interactions in non-syndromic orofacial cleft: a multicenter study in Brazil

BACKGROUND

Associations between the WNT5A rs566926 variant and non-syndromic orofacial cleft (NSOC) have been reported in different populations.

OBJECTIVE

This study aimed to investigate the role of the rs566926 single nucleotide polymorphism (SNP) in WNT5A and its interactions with SNPs in BMP4, FGFR1, GREM1, MMP2, and WNT3 in the occurrence of NSOC in a Brazilian population.

METHODOLOGY

A case-control genetic association study was carried out involving participants from four regions of Brazil, totaling 801 patients with non-syndromic cleft lip with or without cleft palate (NSCL±P), 273 patients with cleft palate only (NSCPO), and 881 health volunteers without any congenital condition (control). Applying TaqMan allelic discrimination assays, we evaluated WNT5A rs566926 in an ancestry-structured multiple logistic regression analysis, considering sex and genomic ancestry as covariates. Interactions between rs566926 and variants in genes involved in the WNT5A signaling pathway (BMP4, FGFR1, GREM1, MMP2, and WNT3) were also explored.

RESULTS

WNT5A rs566926 was significantly associated with an increased risk of NSCL±P, particularly due to a strong association with non-syndromic cleft lip only (NSCLO), in which the C allele increased the risk by 32% (OR: 1.32, 95% CI: 1.04-1.67, p=0.01). According to the proportions of European and African genomic ancestry, the association of rs566926 reached significant levels only in patients with European ancestry. Multiple interactions were detected between WNT5A rs566926 and BMP4 rs2071047, GREM1 rs16969681 and rs16969862, and FGFR1 rs7829058.

CONCLUSION

The WNT5A rs566926 polymorphism was associated with NSCL±P, particularly in individuals with NSCLO and high European ancestry. Epistatic interactions involving WNT5A rs566926 and variants in BMP4, GREM1, and FGFR1 may contribute to the risk of NSCL±P in the Brazilian population.

Maternal consumption of caffeine and second-hand tobacco smoke as risk factors for the development of oral clefts

OBJECTIVE

The aim of this case-control study was to investigate environmental factors, such as caffeine, folic acid, nutritional iron supplementation, multivitamin complexes, alcohol, and tobacco (second-hand smoking), which have been described as risk factors for the development of oral clefts.

METHODS

This case-control study employed convenience sampling and included 409 mothers: 132 with children with oral clefts (cases) and 277 with children without oral clefts (controls). The age range of the children in both groups was 0 to 2 years. A questionnaire was administered to each mother to inquire about their habits and food consumption during the first trimester of pregnancy.

RESULTS

Folic acid supplementation was observed in 116 (87.8%) of the case group (p < 0.001) and 271 (97.8%) of the control group. Regarding the use of ferrous sulfate, 114 (86.3%) of the case group and 271 (97.8%) of the control group reported using it. In the case group, 84 (63.6%) mothers reported being exposed to second-hand smoke, and 5 (3.7%) reported alcohol consumption (p = 0.797). In terms of caffeine consumption, 127 mothers (95.4%) in the case group consumed it (p = 0.13), while 247 (88.8%) reported consumption in the control group.

CONCLUSIONS

The results suggest a direct relationship between secondhand smoke, alcohol consumption, and the lack of maternal supplementation with oral clefts.

Integrating transcriptomics and genomics to identify fibroblast growth factor/receptor candidate genes for non-syndromic orofacial cleft in Chinese

OBJECTIVES

The objective of this study was to explore the relationship between fibroblast growth factor/receptor (FGF/FGFR) and non-syndromic orofacial cleft (NSOC) in individuals of Han Chinese.

DESIGN

Initially, we performed RNA-Seq between non-syndromic cleft lip only (NSCLO) or non-syndromic cleft palate only (NSCPO) and control groups. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were carried out to evaluate the functions of differentially expressed genes (DEGs) of FGF/FGFR. Then, we selected the most significant DEG FGFR2 and performed an association analysis in Chinese. Linkage disequilibrium (LD) and haplotype analyses were performed with HaploView and PLINK. Additional bioinformatics functional prediction for the notable single nucleotide polymorphisms was performed with HaploReg V4.1 and 3DSNP.

RESULTS

Finally, we identified 32 mRNAs related to FGF/FGFR via RNA-Seq and chose FGFR2 in the subsequent association analysis. Results indicated that the single nucleotide polymorphism (SNP) rs2288336 in FGFR2 contributed significantly to both non-syndromic cleft lip with or without cleft palate (NSCL/P) and NSCLO, with p values of 5.00E-05 (OR = 0.79, 95% CI: 0.70-0.88) and 1.38E-04 (OR = 0.76, 95% CI: 0.65-0.87), respectively. In addition, rs3793893 in FGFR2 was found to be associated with NSCLO, with a p value of 1.02E-04 (OR = 0.67, 95% CI: 0.55-0.82).

CONCLUSIONS

Our research demonstrated that FGFR2 is significantly more involved in NSOC than other FGF/FGFRs in Chinese and further identified rs2288336 and rs3793893 in FGFR2 associated with NSOC subtypes, which provide further evidence for the genetic etiology of NSOC in Han Chinese.