Genetics of cleft lip and cleft palate

The potential up-regulation risk of 3' UTR SNP (rs10787760 G > A) for the VAX1 gene is associated with NSCLP in the northwest Chinese population

AIMS

To investigate the association between single nucleotide polymorphisms (SNPs) in 3'UTR region of VAX1, SYT14 and PAX7 genes and the risk of non-syndromic cleft palate (NSCLP) in a northwest Chinese population.

MAIN METHODS

A case-control study was conducted in 406 normal controls and 399 NSCLP patients. Using iMLDRTM genotyping technology, eight SNPs of three genes ((rs10787760, rs7086344 at VAX1), (rs1010113, rs851114, and rs485874 at PAX7), and (rs61820397, rs4609425, rs12133399 at SYT14)) were genotyped to investigate the differences in alleles and genotype distribution frequencies between NSCLP patients and healthy controls. RNA Folding Form software was used to predict RNA secondary structure and expression vectors were constructed to explore the function of the relevant SNP. The effect of SNP polymorphism of gene transcription and translation was assessed using qPCR and Western blot analysis.

KEY FINDINGS

Among the eight SNPs of three genes, rs10787760 of VAX1 gene was found to be associated with an increased risk of NSCLP (OR = 1.341, CI = 1.004-1.790) and the GA genotype of rs10787760 increased the risk of cleft lip and/or palate (CL/P) about 1.42 times (p < 0.05), and carrying the A allele might increase the risk of NSCL/P in male (OR = 1.356, 95 % CI = 1.010-1.823). But there was no association observed with cleft palate only (CPO). Cell function experiments revealed that the G to A mutation in rs10787760 up-regulated GFP-VAX1 transcriptional level by 2.39 and 3.13 times in two cell lines respectively, and enhance the protein expression of the VAX1 gene further. RNA secondary structure study showed that the rs10787760 (G > A) had two different secondary structures in 3'UTR region.

SIGNIFICANCE

The rs10787760 variant in the 3'UTR region of VAX1 gene is associated with CL/P in northwest Chinese population. We hypothesize that the machanism of it might be caused by the RNA differenct fold in the 3'UTR region caused by the polymorphism of the gene.

LEVEL OF EVIDENCE

Original Reports.

Optimization of orofacial cleft imaging protocols using device-specific low-dose cone-beam computed tomography

OBJECTIVE

The aim of this study was to present optimized device-specific low-dose cone-beam computed tomography (CBCT) protocols with sufficient image quality for pre-surgical diagnostics and three-dimensional (3D) modelling of cleft defects.

METHODS

Six paediatric skulls were acquired, and an artificial bony cleft was created. A high-resolution CBCT scan acted as a reference standard (Accuitomo 170, Morita, Kyoto, Japan) for comparing eight low-dose protocols of Newtom VGi-evo (QR Verona, Cefla, Verona, Italy), which included Eco and Regular protocols with different field of views (FOVs). Delineation of lamina dura, cementoenamel junction (CEJ), trabecular bone and bony bridge were assessed. A 3D model of the defect was also evaluated.

RESULT

The dose area product of low-dose protocols ranged from 31 to 254 mGy*cm2. Despite the dose difference of up to eight times between applied protocols, trabecular bone and CEJ exhibited appropriate image quality in all scans. However, Regular small FOV protocols (5 × 5 and 8 × 5 cm2), for both lamina dura and bony bridge, demonstrated a significant improvement in image quality compared to Eco FOV counterparts. Based on 3D defect analysis, no significant difference existed between low-dose protocols and the reference standard.

CONCLUSION

The findings highlight the possibility of achieving a considerable reduction (up to eight times) in the radiation dose using low-dose CBCT protocols while maintaining sufficient image quality for assessing anatomical structures and 3D modelling in cleft cases.

COVID-19 vaccine and non-syndromic orofacial clefts in five arab countries. A case-control study

OBJECTIVES

Risk factors for non-syndromic orofacial cleft (NSOFCs) include genetic profile and environmental exposure to medication and illnesses during pregnancy. We assessed the association between the COVID-19 vaccination and the incidence of NSOFC across five Middle Eastern countries.

MATERIALS AND METHODS

This multi-country, hospital-based, case-control study included infants with NSOFCs whose first 3 intrauterine months coincided with the time when pregnant women were allowed to receive COVID-19 vaccination in the countries participating in the study. Newborns with NSOFCs were examined for cleft type and their parents were interviewed for maternal exposures and COVID-19 vaccination. Controls were newborns matched to cases in gender and setting.

RESULTS

The study recruited 977 (348 children with NSOFCs and 629 controls). Maternal use of nicotine (Adjusted Odds Ratio (AOR): 2.437; P = 0.044) and family history of NSOFC (AOR: 11.059; P < 0.001) increased significantly the AOR of having a child with NSOFC. On the other hand, COVID-19 vaccine administration to pregnant mothers have significantly decreased the AOR of having a child with NSOFC (AOR: 0.337; P = 0.006).

CONCLUSION

This study suggests that COVID-19 vaccination is not related to NSOFC and might protect against having a child affected with such a congenital anomaly.

CLINICAL RELEVANCE

The finding of this study is important for healthcare providers for considering COVID-19 vaccination for pregnant woman. Clear communication and education about the potential risks and benefits would be crucial for informed decision-making. The study's results would directly impact pregnant individuals, as they would need accurate information to make informed decisions about their health and the health of their infants.

Genome-wide study of gene-by-sex interactions identifies risks for cleft palate

Structural birth defects affect 3-4% of all live births and, depending on the type, tend to manifest in a sex-biased manner. Orofacial clefts (OFCs) are the most common craniofacial structural birth defects and are often divided into cleft lip with or without cleft palate (CL/P) and cleft palate only (CP). Previous studies have found sex-specific risks for CL/P, but these risks have yet to be evaluated in CP. CL/P is more common in males and CP is more frequently observed in females, so we hypothesized there would also be sex-specific differences for CP. Using a trio-based cohort, we performed sex-stratified genome-wide association studies (GWAS) based on proband sex followed by a genome-wide gene-by-sex (GxS) interaction testing. There were 13 loci significant for GxS interactions, with the top finding in LTBP1 (RR=3.37 [2.04 - 5.56], p=1.93x10 -6 ). LTBP1 plays a role in regulating TGF-B bioavailability, and knockdown in both mice and zebrafish lead to craniofacial anomalies. Further, there is evidence for differential expression of LTBP1 between males and females in both mice and humans. Therefore, we tested the association between the imputed genetically regulated gene expression of genes with significant GxS interactions and the CP phenotype. We found significant association for LTBP1 in cell cultured fibroblasts in female probands (p=0.0013) but not in males. Taken altogether, we show there are sex-specific risks for CP that are otherwise undetectable in a combined sex cohort, and LTBP1 is a candidate risk gene, particularly in females.

Patterns of primary and secondary defects associated with non-syndromic cleft lip and palate: An epidemiological analysis in a Kenyan population

Cleft lip and palate deformities substantially burden individuals and families, particularly in low-income communities. However, a comprehensive understanding of the patterns and distribution of these deformities in Kenya remains limited. This retrospective cross-sectional study analyzed 647 clinical records from the BelaRisu Foundation registry in Kenya, spanning 2018-2022. After meticulous record verification and data extraction, cleft pattern modeling was used to analyze each case. Data were imported to SPSS version 29.0 and descriptive statistics were calculated, which included means, ranges, frequencies, percentages, and standard deviations. Additionally, a comparative analysis between genders was conducted. The findings revealed a higher average age of presentation compared with previous studies in Kenya, along with a greater susceptibility of males to cleft lip and palate defects overall. Noteworthy disparities in case distribution across provinces were observed. Cleft lip emerged as the most observed primary defect, while palatal fistulae constituted the most frequent secondary defect. Interestingly, while some results aligned with global trends, others diverged significantly from the existing literature, warranting further exploration and investigation. These findings shed light on the unique patterns and distribution of cleft lip and palate deformities in Kenya, highlighting the need for targeted interventions and support systems.

The heterogeneous genetic architectures of orofacial clefts

Orofacial clefts (OFCs) are common, affecting 1:1000 live births. OFCs occur across a phenotypic spectrum - including cleft lip (CL), cleft lip and palate (CLP), or cleft palate (CP) - and can be further subdivided based on laterality, severity, or specific structures affected. Herein we review what is known about the genetic architecture underlying each of these subtypes, considering both shared and subtype-specific risks. While there are more known genetic similarities between CL and CLP than CP, recent research supports both shared and subtype-specific genetic risk factors within and between phenotypic classifications of OFCs. Larger sample sizes and deeper phenotyping data will be of increasing importance for the discovery of novel genetic risk factors for OFCs and various subtypes going forward.

History of Eugenics in Otorhinolaryngology: Ernst Rüdin and the International Eugenics Network

Introduction  The early geneticist and psychiatrist Ernst Rüdin (1874-1952) became one of the key figures in the eugenics movement and in the German health system of the Nazi era. His connections in the international eugenics network have played an important role in the history of eugenics. Objective  To discuss the connections between Ernst Rüdin's scientific group in Munich and Otmar von Verschuer's group in Frankfurt during the Nazi era. Methods  Otorhinolaryngological materials from Ernst Rüdin's former private library are presented, and they show Rüdin's deep involvement in the international eugenics network. These materials provide insights into early medical genetics in otorhinolaryngology. Results  One result of the present study is that eugenics groups from Munich, Frankfurt, and New York certainly influenced one another in the field of otorhinolaryngology. Karlheinz Idelberger and Josef Mengele were two scientists who performed hereditary research on orofacial clefts. Later, Mengele became deeply involved in Nazi medical crimes. His former work on orofacial clefts clearly had, to some extent, an influence on subsequent studies. Conclusion  An international eugenics network already existed before 1933. However, it becomes clear that the weaknesses of many early genetic studies did not enable its authors to draw firm scientific conclusions, suggesting that scientists lacked an accurate concept of the genetic causes of most illnesses.

Stem Cell-Based Regenerative Approaches for the Treatment of Cleft Lip and Palate: A Comprehensive Review

Cleft lip and/or palate (CLP) is a prevalent congenital craniofacial abnormality that can lead to difficulties in eating, speaking, hearing, and psychological distress. The traditional approach for treating CLP involves bone graft surgery, which has limitations, post-surgical complications, and donor site morbidity. However, regenerative medicine has emerged as a promising alternative, employing a combination of stem cells, growth factors, and scaffolds to promote tissue regeneration. This review aims to provide a comprehensive overview of stem cell-based regenerative approaches in the management of CLP. A thorough search was conducted in the Medline/PubMed and Scopus databases, including cohort studies, randomized controlled trials, case series, case controls, case reports, and animal studies. The identified studies were categorized into two main groups: clinical studies involving human subjects and in vivo studies using animal models. While there are only a limited number of studies investigating the combined use of stem cells and scaffolds for CLP treatment, they have shown promising results. Various types of stem cells have been utilized in conjunction with scaffolds. Importantly, regenerative methods have been successfully applied to patients across a broad range of age groups. The collective findings derived from the reviewed studies consistently support the notion that regenerative medicine holds potential advantages over conventional bone grafting and represents a promising therapeutic option for CLP. However, future well-designed clinical trials, encompassing diverse combinations of stem cells and scaffolds, are warranted to establish the clinical efficacy of these interventions with a larger number of patients.

[Clinical Characteristics Analysis of 1051 Cases of Cleft Lip With/Without Cleft Palate in the Ethnic Tibetan Population]

Objective

To examine the characteristics of the prevalence of congenital cleft lip with/without cleft palate in the ethnic Tibetan population and to provide support for the precise prevention and treatment of cleft lip with/without cleft palate in the Tibetan population.

Methods

The clinical data of Tibetan patients with cleft lip with/without cleft palate were collected and the clinical characteristics of the patients were analyzed. The patients' age ranged from 2 months to 51 years old. All the subjects were admitted to West China Stomatology Hospital, Sichuan University for the treatment of cleft lip with/without cleft palate between January 2016 and August 2023. Most of the subjects came from Sichuan Province and the Tibet Autonomous Region.

Results

A total of 1051 patients were enrolled and children aged under 12 months (460 cases) accounted for the largest proportion. Among the subjects, 383 had cleft lip only (36.44%), 140 had cleft palate only (13.32%), and 528 had cleft lip with cleft palate (50.24%). The male-to-female ratios of patients with cleft lip only (0.99∶1), cleft palate only (0.54∶1), and cleft lip with cleft palate (1.67∶1) exhibited significant differences (P<0.001). However, there was no significant difference in the male-to-female ratio in patients with cleft lip only or those with cleft lip with cleft palate when the subjects were divided into two groups according to whether they had unilateral or bilateral cleft lip with/without cleft palate. Most of the patients with bilateral cleft lip were female, while most of the patients with unilateral cleft lip and unilateral or bilateral cleft lip with cleft palate were male. The unilateral cleft lip with/without cleft palate was located predominantly on the left side. Syndromic cleft lip with/without cleft palate accounted for 3.43% of all the cases and the most common concomitant deformity was congenital heart disease. 3.81% (40 cases) of the patients had a family history. In the patients with cleft lip only and those with cleft palate only, the proportion of patients having parents with corresponding phenotypes was higher than those of other phenotypes of cleft lip with/without cleft palate. Regarding the birth time distribution of the children with cleft lip with/without cleft palate, Spring saw the highest number of births of these children (311 cases, 29.59%), while Winter saw the lowest number of births (231 cases, 21.98%).

Conclusion

The cases of cleft lip with/without cleft palate in the ethnic Tibetan population are predominantly cleft lip and palate. Unilateral cleft lip only or cleft lip with palate is predominantly located on the left side. Lip disease phenotypes may be more heritable.

The Hard Palate Sweep: a multiplanar 2-dimensional sonographic method for the prenatal detection of cleft palate

BACKGROUND

Prenatal diagnosis of cleft palate is challenging. Numerous 2-dimensional and 3-dimensional methods have been proposed to assess the integrity of the fetal palate, yet detection rates remain relatively low. We propose the "Hard Palate Sweep," a novel 2-dimensional method that enables clear demonstration of the entire fetal palate throughout pregnancy, in a single sweep, avoiding acoustic shadows cast by surrounding bones.

OBJECTIVE

This study aimed to assess the feasibility and performance of the Hard Palate Sweep, performed throughout pregnancy.

STUDY DESIGN

This was a prospective cross-sectional study performed between 2018 and 2022 in pregnant patients referred for a routine or targeted anomaly scan between 13 and 40 weeks of gestation. The presence or absence of a cleft palate was determined using the "Hard Palate Sweep." This was compared with the postnatal palate integrity assessment. Test feasibility and performance indices, including sensitivity, specificity, and positive and negative predictive values were calculated. Offline clips were reviewed by 2 investigators for the assessment of inter- and intraoperator agreement, using Cohen's kappa formula. The study protocol was approved by the institutional ethics committee. All participating patients were informed and provided consent.

RESULTS

A total of 676 fetuses were included in the study. The Hard Palate Sweep was successfully performed in all cases, and 19 cases were determined to have a cleft palate. Of these, 13 cases were excluded because postmortem confirmation was not performed, leaving 663 cases available for analysis. Six cases determined to have a cleft palate were confirmed postnatally. In 655 of 657 cases prenatally determined to have an intact palate, this was confirmed postnatally. In the 2 remaining cases, rare forms of cleft palate were diagnosed postnatally, rendering 75% sensitivity, 100% specificity, 100% positive predictive value, and 99.7% negative predictive value for the Hard Palate Sweep (P<.001). There was complete intra- and interoperator agreement (kappa=1; P<.0001).

CONCLUSION

The Hard Palate Sweep is a feasible and accurate method for prenatally detecting a cleft palate. It was successfully performed in all attempted cases between 13 and 40 weeks of gestation. This method is reproducible, offering high sensitivity and specificity. Implemented routinely, the Hard Palate Sweep is expected to increase the prenatal detection of cleft palate.

Evaluating Dental Arch Relationships in Indonesian Patients with Operated Bilateral Cleft Lip and Palate Using Modified Huddart/Bodenham Index and Bauru-bilateral cleft lip and palate (BCLP) Yardstick

Background

Patients with complete bilateral cleft lip and palate (CBCLP) have the most complex orofacial abnormalities despite its lowest incidence among cleft lip and palate (CLP) types. Impaired maxillary growth can result from surgical procedures in patients with CBCLP. This study evaluates dental arch relationships in Indonesian patients with CBCLP after undergoing CLP repair at Harapan Kita Children and Mother Hospital in Jakarta.

Material and Methods

Using the modified Huddart and Bodenham (MHB) index and Bauru bilateral cleft lip and palate (BCLP) yardstick, three examiners assessed 17 study models in the 9-year age group and 13 study models in the 12-year age group, as well as two intraoral clinical photographs of two patients with CBCLP. The assessments were repeated three times within two weeks of each assessment time.

Results

Patients with operated CBCLP (aged 9 and 12 years) had edge-to-edge tooth relations, which were categorized as a mild crossbite or mild deviation, and only required orthodontic treatment according to the two specified indicators.

Conclusions

The CLP repair protocol used at the Harapan Kita Hospital effectively manages CBCLP cases with satisfactory results, suggesting the effectiveness of the MHB index and Bauru-BCLP yardstick in assessing dental arch relationships in patients with operated CBCLP. Key words:Bilateral, cleft lip and palate, dental arch relationship, lip repair, palate repair.

A comprehensive consolidation of data on the relationship between IRF6 polymorphisms and non-syndromic cleft lip/palate susceptibility: From 79 case-control studies

BACKGROUND

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is a prevalent craniofacial birth defect on a global scale. A number of candidate genes have been identified as having an impact on NSCL/P. However, the association between interferon regulatory factor 6 (IRF6) polymorphisms and NSCL/P has yielded inconsistent results, prompting the need for a meta-analysis to obtain more accurate estimates.

METHODS

We conducted a thorough screening of all relevant articles published up until November 15, 2023, in online bibliographic databases. The statistical analysis of the collected data was performed using the Comprehensive Meta-Analysis (Version 4.0) software.

RESULTS

A total of 79 case-control studies, comprising 14,003 cases and 19,905 controls, were included in our analysis. The combined data indicated that the IRF6 rs642961 and rs2235371 polymorphisms were associated with an increased risk of NSCL/P in the overall population. However, no significant association was found between the rs2013162 and rs2235375 polymorphisms and the risk of NSCL/P in the overall population. Furthermore, subgroup analyses revealed significant correlations between the IRF6 rs642961, rs2235371, and rs2235375 polymorphisms and the risk of NSCL/P based on ethnic background and country of origin. Nevertheless, the rs2013162 polymorphism plays a protective role in Caucasians and mixed populations.

CONCLUSIONS

Our collective data indicates a significant association between the rs642961 and rs2235371 polymorphisms and the risk of NSCL/P in the overall population. The rs2235375 polymorphism could influence the susceptibility to NSCL/P based on ethnic background. Meanwhile, the rs2013162 polymorphism provides protective effects in Caucasian, mixed populations, and the Brazilian population.

Cleft Lip Repair and Primary and Intermediate Cleft Rhinoplasties

The cleft lip is one of the most common craniofacial abnormalities seen worldwide. The lip and primary rhinoplasty repairs are performed together in a single surgery for patients aged 3 to 6 months. The intermediate rhinoplasty has fallen out of favor due to more advanced approaches at primary rhinoplasty. However, it still plays a role in addressing severe nasal airway obstruction or correcting anatomic differences causing emotional distress from social ridicule. The article reviews the incidence of cleft lip, discusses its development and variant anatomy, and examines the approaches to surgical repair of the cleft clip, primary and intermediate rhinoplasties.

Craniofacial anomalies in a murine model of heterozygous fibroblast growth factor 10 gene mutation

OBJECTIVE

Dysregulation of Fibroblast Growth Factor 10 (FGF10), a member of the family of Fibroblast Growth Factor (FGF) proteins, has been implicated in craniofacial and dental anomalies, including craniosynostosis, cleft palate, and Lacrimo-Auriculo-Dento-Digital Syndrome. The aim of this murine study was to assess the craniofacial and dental phenotypes associated with a heterozygous FGF10 gene (FGF10+/- ) mutation at skeletal maturity.

METHODS

Skulls of 40 skeletally mature mice, comprising two genotypes (heterozygous FGF10+/- mutation, n = 22; wildtype, n = 18) and two sexes (male, n = 23; female, n = 17), were subjected to micro-computed tomography. Landmark-based linear dimensions were measured for the cranial vault, maxilla, mandible, and first molar teeth. Multivariate analysis of variance was performed to assess whether there were significant differences in the craniofacial and dental structures between genotypes and sexes.

RESULTS

The craniomaxillary skeleton and the first molar teeth were smaller in the FGF10+/- mice (P < .05), but the mandible was unaffected. Sex did not have a significant effect on these structures (P > .05). Cranial sutural defects were noted in 5/22 (22.7%) mutant versus 2/18 (11.1%) wildtype mice, and cleft palate in only one (4.5%) mutant mouse. None of the mice displayed craniosynostosis, expansive bony lesions, bifid condyles, or impacted teeth.

CONCLUSION

The FGF10+/- mutation was associated with craniomaxillary skeletal hypoplasia that probably arose from deficient (delayed) intramembranous ossification of the sutured bones. Overall, the skeletal and dental data suggest that the FGF10 gene plays an important role in the aetiology of craniofacial dysmorphology and malocclusion.

Towards solving the genetic diagnosis odyssey in Iranian patients with congenital anomalies

Understanding the underlying causes of congenital anomalies (CAs) can be a complex diagnostic journey. We aimed to assess the efficiency of exome sequencing (ES) and chromosomal microarray analysis (CMA) in patients with CAs among a population with a high fraction of consanguineous marriage. Depending on the patient's symptoms and family history, karyotype/Quantitative Fluorescence- Polymerase Chain Reaction (QF-PCR) (n = 84), CMA (n = 81), ES (n = 79) or combined CMA and ES (n = 24) were performed on 168 probands (66 prenatal and 102 postnatal) with CAs. Twelve (14.28%) probands were diagnosed by karyotype/QF-PCR and seven (8.64%) others were diagnosed by CMA. ES findings were conclusive in 39 (49.36%) families, and 61.90% of them were novel variants. Also, 64.28% of these variants were identified in genes that follow recessive inheritance in CAs. The diagnostic rate (DR) of ES was significantly higher than that of CMA in children from consanguineous families (P = 0·0001). The highest DR by CMA was obtained in the non-consanguineous postnatal subgroup and by ES in the consanguineous prenatal subgroup. In a population that is highly consanguineous, our results suggest that ES may have a higher diagnostic yield than CMA and should be considered as the first-tier test in the evaluation of patients with congenital anomalies.

Disruption of DNA methylation-mediated cranial neural crest proliferation and differentiation causes orofacial clefts in mice

Orofacial clefts of the lip and palate are widely recognized to result from complex gene-environment interactions, but inadequate understanding of environmental risk factors has stymied development of prevention strategies. We interrogated the role of DNA methylation, an environmentally malleable epigenetic mechanism, in orofacial development. Expression of the key DNA methyltransferase enzyme DNMT1 was detected throughout palate morphogenesis in the epithelium and underlying cranial neural crest cell (cNCC) mesenchyme, a highly proliferative multipotent stem cell population that forms orofacial connective tissue. Genetic and pharmacologic manipulations of DNMT activity were then applied to define the tissue- and timing-dependent requirement of DNA methylation in orofacial development. cNCC-specific Dnmt1 inactivation targeting initial palate outgrowth resulted in OFCs, while later targeting during palatal shelf elevation and elongation did not. Conditional Dnmt1 deletion reduced cNCC proliferation and subsequent differentiation trajectory, resulting in attenuated outgrowth of the palatal shelves and altered development of cNCC-derived skeletal elements. Finally, we found that the cellular mechanisms of cleft pathogenesis observed in vivo can be recapitulated by pharmacologically reducing DNA methylation in multipotent cNCCs cultured in vitro. These findings demonstrate that DNA methylation is a crucial epigenetic regulator of cNCC biology, define a critical period of development in which its disruption directly causes OFCs, and provide opportunities to identify environmental influences that contribute to OFC risk.

How are people with orofacial clefts attended in northwest region of São Paulo state, Brazil?

Characterization of specific birth defects is essential for conducting scientific investigations, care and therapeutic strategies. This article describes demographic, clinical and genetic aspects, risk factors and access to treatment of Brazilian patients with orofacial clefts registered in a specialized collaborative center of the Brazilian Database on Craniofacial Anomalies (BDCA). We interviewed 70 individuals with typical orofacial clefts using a standard instrument from the database and subjected them to genetic testing. The patients were grouped as syndromic and non-syndromic. The majority of individuals were of lower middle class, native ancestry and syndromic. There was a significant difference in the type of clefts regarding gender. There was no significant difference between bilateral and unilateral, between the side affected, right and left, or familial recurrence related to type of oral cleft. The risk factor familial recurrence was significantly higher among non-syndromic cases. Etiological factors were identified or suggested in 62.5% of the syndromic cases. There was a delay in diagnosis and in access to treatment in most cases. We concluded that gender, native ancestry and low family income represent risk factors. Furthermore, the distribution by cleft types and gender is similar to previous studies. The results can guide scientific investigations and care policies.

A Rare Case of Cleft Palate Associated With Tongue Hamartoma: A Case Report and Systematic Review

INTRODUCTION

Palate development involves a genetic regulation through a complex molecular mechanism that may be disrupted by environmental factors, resulting in impaired fusion and cleft palate formation. An encounter with a case of cleft palate due to dorsal tongue hamartoma prompted us to perform this systematic review.

OBJECTIVE

To review the clinical profile and management approach for a case with cleft palate and tongue hamartoma.

DESIGN

A systematic literature search was conducted using keywords related to cleft palate and tongue hamartoma in PubMed, Scopus, MEDLINE, and Scielo databases through December 2021, with no time or language restrictions.

PATIENTS, PARTICIPANTS

Studies reporting patients with cleft palate and tongue hamartoma were included.

MAIN OUTCOME MEASURE(S)

Information related to clinical profile, diagnostic tests, histopathology, management, and outcomes were extracted.

Fourteen relevant publications were identified with 16 cases reported so far. Among them, thirteen patients were females (81.25%), and 3 were males (18.75%). The age of presentation varied from birth to 19 years. Oral-facial-digital syndrome (type II) was the most commonly associated syndrome.

Congenital tongue hamartoma with cleft palate is a rare presentation, which can present as an isolated entity or part of a syndrome. Genetic evaluation is warranted, particularly for multiple hamartomatous lesions. The preferred treatment is immediate excision of hamartoma while following a standard timeline for palatoplasty.

Radiographic Assessment of Different Autogenous Bone Grafts in the Alveolar Cleft: A Retrospective Longitudinal Study

Objectives

To assess feasibility and maintenance of bone after alveolar cleft reconstructions using graft from iliac crest and mandibular symphysis.

Methods

51 alveolar clefts grafted with iliac crest and 51 ones grafted with mandibular symphysis bones were selected from patients aged between 7 and 12 years. At three (T1) and 12 months (T2) after surgeries, periapical radiographs were performed to measure the height of the grafted bone based on the modified Bergland scale. Chi-square and Mann-Whitney-Wilcoxon tests compared differences between T1 and T2 according to each bone graft.

Results

From the clefts grafted with mandibular symphysis bone, 47 were classified as type I (92.5%) and 04 as type II (7.84%) at T1. At T2, 36 were classified as type II (25.49%) and 02 as type III (3.92%). In the analysis of the clefts grafted with iliac crest at T1, 48 were classified as type I (94.11%) and three as type II (5.88%). At T2, 37 classifieds as type I (72.54%), 12 as type II (23.52%) and two as type III (3.92%). There was no statistically significant difference between treatments.

Conclusions

It was concluded that iliac crest and mandibular symphysis are adequate areas from which bone grafts can be obtained for reconstruction of alveolar cleft.

Wideband Tympanometry (WBT) Features in Children with Cleft Palate and Otitis Media with Effusion Before and After Cleft Palate Surgery

Aims

In some cases, children with cleft palate undergo unnecessary tympanostomy along with palatoplasty because of inaccurate evaluations in determining the level of otitis media with effusion (OME). Recent studies have shown that wideband tympanometry (WBT) significantly contributes to the accurate evaluation of the middle ear status in children with cleft palate. Therefore, this study aimed to investigate WBT and auditory brainstem response (ABR) indices before and after cleft palate repair surgery.

Materials and Methods

The study involved 88 children with cleft palate, and ABR and WBT energy absorbance indices were measured in two phases. The first phase was conducted three months and three days prior to cleft palate repair surgery, and the second phase was carried out one, three, and six months after surgery.

Results

In the first phase, the energy absorbance index of low frequencies was below the normal range in all children, within the normal range at high frequencies in 78 children, and below the normal range in only 10 children three months before cleft palate surgery. In the second phase, the energy absorbance index and hearing thresholds at low frequencies after surgery showed a significant difference compared with the preoperative index (p = 0.001).

Conclusion

Monitoring WBT indices and hearing thresholds in children with cleft palate is effective in determining the appropriate surgery for children with otitis media with effusion (OME). Furthermore, the WBT plays a crucial role in accurately assessing middle ear function after cleft palate surgery.

Oral Cleft and Maternal History of Spontaneous Abortion: A Case-Control Study

To investigate and compare the occurrence of previous spontaneous abortion among mothers of children with nonsyndromic oral clefts (NSOC) and mothers of children without NSOC; to understand if previous spontaneous abortion could be a risk factor for the occurrence of NSOC in subsequent pregnancies.

Case-control study.

Nonsyndromic oral clefts is an important public health problem. In the context of investigating risk factors for the occurrence of this malformation, previous spontaneous abortion have been considered in the etiology at NSOC.

There were 1004 participants. In the case group 502 mothers of children with NSOC, and in the control group 502 mothers of children without NSOC or any other malformation or syndrome.

A standardized questionnaire was utilized to interview the maternal history of spontaneous abortion.

The data were evaluated using descriptive statistics, and comparisons were performed using the Chi-square test, adopting a significance level of 5%.

The prevalence of maternal history of spontaneous abortion was 16.3% in the case group and 15.9% in the control group. Comparing the groups there was no statistical difference (p-value = 0.93). Analyzing the occurrence of previous spontaneous abortion, separating the case group according to the type of cleft in the child, no statistical differences were observed when comparing these groups between them.

Maternal history of spontaneous abortion was not associated with NSOC, not representing an independent risk factor for NSOC in the Brazilian population.

Association between IRF6, TP63, GREM1 Gene Polymorphisms and Non-Syndromic Orofacial Cleft Phenotypes in Vietnamese Population: A Case-Control and Family-Based Study

This study aims to identify potential variants in the TP63-IRF6 pathway and GREM1 for the etiology of non-syndromic orofacial cleft (NSOFC) among the Vietnamese population. By collecting 527 case-parent trios and 527 control samples, we conducted a stratified analysis based on different NSOFC phenotypes, using allelic, dominant, recessive and over-dominant models for case-control analyses, and family-based association tests for case-parent trios. Haplotype and linkage disequilibrium analyses were also conducted. IRF6 rs2235375 showed a significant association with an increased risk for non-syndromic cleft lip and palate (NSCLP) and cleft lip with or without cleft palate (NSCL/P) in the G allele, with pallele values of 0.0018 and 0.0003, respectively. Due to the recessive model (p = 0.0011) for the NSCL/P group, the reduced frequency of the GG genotype of rs2235375 was associated with a protective effect against NSCL/P. Additionally, offspring who inherited the G allele at rs2235375 had a 1.34-fold increased risk of NSCL/P compared to the C allele holders. IRF6 rs846810 and a G-G haplotype at rs2235375-rs846810 of IRF6 impacted NSCL/P, with p-values of 0.0015 and 0.0003, respectively. In conclusion, our study provided additional evidence for the association of IRF6 rs2235375 with NSCLP and NSCL/P. We also identified IRF6 rs846810 as a novel marker associated with NSCL/P, and haplotypes G-G and C-A at rs2235375-rs846810 of IRF6 associated with NSOFC.

Trio-based GWAS identifies novel associations and subtype-specific risk factors for cleft palate

Cleft palate (CP) is one of the most common craniofacial birth defects; however, there are relatively few established genetic risk factors associated with its occurrence despite high heritability. Historically, CP has been studied as a single phenotype, although it manifests across a spectrum of defects involving the hard and/or soft palate. We performed a genome-wide association study using transmission disequilibrium tests of 435 case-parent trios to evaluate broad risks for any cleft palate (ACP) (n = 435), and subtype-specific risks for any cleft soft palate (CSP), (n = 259) and any cleft hard palate (CHP) (n = 125). We identified a single genome-wide significant locus at 9q33.3 (lead SNP rs7035976, p = 4.24 × 10-8) associated with CHP. One gene at this locus, angiopoietin-like 2 (ANGPTL2), plays a role in osteoblast differentiation. It is expressed both in craniofacial tissue of human embryos and developing mouse palatal shelves. We found 19 additional loci reaching suggestive significance (p < 5 × 10-6), of which only one overlapped between groups (chromosome 17q24.2, ACP and CSP). Odds ratios for the 20 loci were most similar across all 3 groups for SNPs associated with the ACP group, but more distinct when comparing SNPs associated with either subtype. We also found nominal evidence of replication (p < 0.05) for 22 SNPs previously associated with orofacial clefts. Our study to evaluate CP risks in the context of its subtypes and we provide newly reported associations affecting the broad risk for CP as well as evidence of subtype-specific risks.

Rare variant modifier analysis identifies variants in SEC24D associated with orofacial cleft subtypes

As one of the most common structural birth defects, orofacial clefts (OFCs) have been studied for decades, and recent studies have demonstrated that there are genetic differences between the different phenotypic presentations of OFCs. However, the contribution of rare genetic variation genome-wide to different subtypes of OFCs has been understudied, with most studies focusing on common genetic variation or rare variation within targeted regions of the genome. Therefore, we used whole-genome sequencing data from the Gabriella Miller Kids First Pediatric Research Program to conduct a gene-based burden analysis to test for genetic modifiers of cleft lip (CL) vs cleft lip and palate (CLP). We found that there was a significantly increased burden of rare variants in SEC24D in CL cases compared to CLP cases (p = 6.86 [Formula: see text] 10-7). Of the 15 variants within SEC24D, 53.3% were synonymous, but overlapped a known craniofacial enhancer. We then tested whether these variants could alter predicted transcription factor binding sites (TFBS), and found that the rare alleles destroyed binding sites for 9 transcription factors (TFs), including Pax1 (p = 0.0009), and created binding sites for 23 TFs, including Pax6 (p = 6.12 [Formula: see text] 10-5) and Pax9 (p = 0.0001), which are known to be involved in normal craniofacial development, suggesting a potential mechanism by which these synonymous variants could have a functional impact. Overall, this study indicates that rare genetic variation may contribute to the phenotypic heterogeneity of OFCs and suggests that regulatory variation may also contribute and warrant further investigation in future studies of genetic variants controlling risk to OFC.

Knowledge assessment on cleft lip and palate among recently graduated dentists: a cross-sectional study

BACKGROUND

The complex presentation, associated co-morbidities and multi-disciplinary requirements dictate the requirement for in-depth knowledge in order to effectively manage patients with cleft lip and palate (CLP). We aimed to develop a validated questionnaire for cleft lip and palate knowledge assessment and to evaluate the knowledge of cleft lip and palate among a group of recently-graduated dentists.

MATERIALS AND METHODS

A multiple-site, cross-sectional questionnaire-based study was conducted. The study population included recently graduated dentists involved in a dental internship program. A bespoke questionnaire was developed and validated, with internal consistency assessed using Cronbach's alpha and factor analysis performed. A 47-item prototype was distilled into a 15-item questionnaire. This was distributed to the participants with a response rate of 67% obtained.

RESULTS

The overall proportion of correct responses among dental interns was moderate (73%). The best results were found in relation to CLP treatment including the effect of unfavorable surgical outcomes on speech (89.5%) and the impact of CLP on the occlusion (87.6%). The lowest rate of correct responses (26.7%) was identified in relation to the association between CLP and smoking.

CONCLUSION

A validated CLP questionnaire was developed, permitting evaluation of the knowledge of cleft lip and palate and its management among recently graduated dentists. There is limited appreciation among dental interns of the risk factors for CLP as well as post-surgical complications. Given that general dentists are often the gatekeepers for the management of patients with cleft lip and palate, it is important that the findings of this survey are used to inform the curriculum and teaching of cleft lip and palate.

Genetic Inheritance Models of Non-Syndromic Cleft Lip with or without Palate: From Monogenic to Polygenic

Non-syndromic cleft lip with or without palate (NSCL/P) is a prevalent birth defect that affects 1/500-1/1400 live births globally. The genetic basis of NSCL/P is intricate and involves both genetic and environmental factors. In the past few years, various genetic inheritance models have been proposed to elucidate the underlying mechanisms of NSCL/P. These models range from simple monogenic inheritance to more complex polygenic inheritance. Here, we present a comprehensive overview of the genetic inheritance model of NSCL/P exemplified by representative genes and regions from both monogenic and polygenic perspectives. We also summarize existing association studies and corresponding loci of NSCL/P within the Chinese population and highlight the potential of utilizing polygenic risk scores for risk stratification of NSCL/P. The potential application of polygenic models offers promising avenues for improved risk assessment and personalized approaches in the prevention and management of NSCL/P individuals.

Development of Artificial Neural Network-Based Prediction Model for Evaluation of Maxillary Arch Growth in Children with Complete Unilateral Cleft Lip and Palate

INTRODUCTION

Cleft lip and palate (CLP) are the most common congenital craniofacial deformities that can cause a variety of dental abnormalities in children. The purpose of this study was to predict the maxillary arch growth and to develop a neural network logistic regression model for both UCLP and non-UCLP individuals.

METHODS

This study utilizes a novel method incorporating many approaches, such as the bootstrap method, a multi-layer feed-forward neural network, and ordinal logistic regression. A dataset was created based on the following factors: socio-demographic characteristics such as age and gender, as well as cleft type and category of malocclusion associated with the cleft. Training data were used to create a model, whereas testing data were used to validate it. The study is separated into two phases: phase one involves the use of a multilayer neural network and phase two involves the use of an ordinal logistic regression model to analyze the underlying association between cleft and the factors chosen.

RESULTS

The findings of the hybrid technique using ordinal logistic regression are discussed, where category acts as both a dependent variable and as the study's output. The ordinal logistic regression was used to classify the dependent variables into three categories. The suggested technique performs exceptionally well, as evidenced by a Predicted Mean Square Error (PMSE) of 2.03%.

CONCLUSION

The outcome of the study suggests that there is a strong association between gender, age, and cleft. The difference in width and length of the maxillary arch in UCLP is mainly related to the severity of the cleft and facial growth pattern.

A non-coding insertional mutation of Grhl2 causes gene over-expression and multiple structural anomalies including cleft palate, spina bifida and encephalocele

Orofacial clefts, including cleft lip and palate (CL/P) and neural tube defects (NTDs) are among the most common congenital anomalies, but knowledge of the genetic basis of these conditions remains incomplete. The extent to which genetic risk factors are shared between CL/P, NTDs and related anomalies is also unclear. While identification of causative genes has largely focused on coding and loss of function mutations, it is hypothesized that regulatory mutations account for a portion of the unidentified heritability. We found that excess expression of Grainyhead-like 2 (Grhl2) causes not only spinal NTDs in Axial defects (Axd) mice but also multiple additional defects affecting the cranial region. These include orofacial clefts comprising midline cleft lip and palate and abnormalities of the craniofacial bones and frontal and/or basal encephalocele, in which brain tissue herniates through the cranium or into the nasal cavity. To investigate the causative mutation in the Grhl2Axd strain, whole genome sequencing identified an approximately 4 kb LTR retrotransposon insertion that disrupts the non-coding regulatory region, lying approximately 300 base pairs upstream of the 5' UTR. This insertion also lies within a predicted long non-coding RNA, oriented on the reverse strand, which like Grhl2 is over-expressed in Axd (Grhl2Axd) homozygous mutant embryos. Initial analysis of the GRHL2 upstream region in individuals with NTDs or cleft palate revealed rare or novel variants in a small number of cases. We hypothesize that mutations affecting the regulation of GRHL2 may contribute to craniofacial anomalies and NTDs in humans.

Parental Accompaniment in Operating Rooms Reduces Child Anxiety

BACKGROUND

We believe that parental presence before the induction of anesthesia for surgery among children with a cleft palate/lip would be effective in mitigating their preoperative anxiety.

OBJECTIVE

We assessed the states of patients with a cleft palate/lip when their parents accompanied them into operating rooms and clarified their and their parents' cognition using a questionnaire.

METHODS

Data were collected via nursing observation when patients and their parents entered the operating room. Furthermore, an anonymous questionnaire was administered to patients and parents after the operation regarding their feelings about parental presence in the operating room.

RESULTS

In total, nine patients cried when they entered the surgical room. Furthermore, six patients and three parents reported preoperative anxiety. In addition, eight patients agreed that they were satisfied with the presence of their parents before induction.

CONCLUSION

Approximately half of the patients cried. However, the presence of parents before the induction of anesthesia was effective in reducing anxiety among most patients and their parents.

Orofacial Clefts: Genetics of Cleft Lip and Palate

Orofacial clefting is considered one of the commonest birth defects worldwide. It presents as cleft lip only, isolated cleft palate or cleft lip and palate. The condition has a diverse genetic background influenced by gene-gene and gene-environment interaction, resulting in two main types, syndromic and nonsyndromic orofacial clefts. Orofacial clefts lead to significant physiological difficulties that affect feeding, speech and language development and other developmental aspects, which results in an increased social and financial burden on the affected individuals and their families. The management of cleft lip and palate is solely based on following a multidisciplinary team approach. In this narrative review article, we briefly summarize the different genetic causes of orofacial clefts and discuss some of the common syndromes and the approach to the management of orofacial clefts.

Integrative analysis of transcriptome dynamics during human craniofacial development identifies candidate disease genes

Craniofacial disorders arise in early pregnancy and are one of the most common congenital defects. To fully understand how craniofacial disorders arise, it is essential to characterize gene expression during the patterning of the craniofacial region. To address this, we performed bulk and single-cell RNA-seq on human craniofacial tissue from 4-8 weeks post conception. Comparisons to dozens of other human tissues revealed 239 genes most strongly expressed during craniofacial development. Craniofacial-biased developmental enhancers were enriched +/- 400 kb surrounding these craniofacial-biased genes. Gene co-expression analysis revealed that regulatory hubs are enriched for known disease causing genes and are resistant to mutation in the normal healthy population. Combining transcriptomic and epigenomic data we identified 539 genes likely to contribute to craniofacial disorders. While most have not been previously implicated in craniofacial disorders, we demonstrate this set of genes has increased levels of de novo mutations in orofacial clefting patients warranting further study.

Gene Regulatory Networks and Signaling Pathways in Palatogenesis and Cleft Palate: A Comprehensive Review

Palatogenesis is a complex and intricate process involving the formation of the palate through various morphogenetic events highly dependent on the surrounding context. These events comprise outgrowth of palatal shelves from embryonic maxillary prominences, their elevation from a vertical to a horizontal position above the tongue, and their subsequent adhesion and fusion at the midline to separate oral and nasal cavities. Disruptions in any of these processes can result in cleft palate, a common congenital abnormality that significantly affects patient's quality of life, despite surgical intervention. Although many genes involved in palatogenesis have been identified through studies on genetically modified mice and human genetics, the precise roles of these genes and their products in signaling networks that regulate palatogenesis remain elusive. Recent investigations have revealed that palatal shelf growth, patterning, adhesion, and fusion are intricately regulated by numerous transcription factors and signaling pathways, including Sonic hedgehog (Shh), bone morphogenetic protein (Bmp), fibroblast growth factor (Fgf), transforming growth factor beta (Tgf-β), Wnt signaling, and others. These studies have also identified a significant number of genes that are essential for palate development. Integrated information from these studies offers novel insights into gene regulatory networks and dynamic cellular processes underlying palatal shelf elevation, contact, and fusion, deepening our understanding of palatogenesis, and facilitating the development of more efficacious treatments for cleft palate.

Genetics and orofacial clefts: a clinical perspective

Orofacial clefts (OFCs) are the most common congenital craniofacial anomaly seen in humans. Most OFCs are sporadic and isolated - these are thought to be multifactorial in origin. Chromosomal and monogenic variants account for the syndromic forms and for some of the non-syndromic inherited forms. This review discusses the importance of genetic testing and the current clinical strategy to deliver a genomics service that is of direct benefit to patients and their families.

Neural crest E-cadherin loss drives cleft lip/palate by epigenetic modulation via pro-inflammatory gene-environment interaction

Gene-environment interactions are believed to play a role in multifactorial phenotypes, although poorly described mechanistically. Cleft lip/palate (CLP), the most common craniofacial malformation, has been associated with both genetic and environmental factors, with little gene-environment interaction experimentally demonstrated. Here, we study CLP families harbouring CDH1/E-Cadherin variants with incomplete penetrance and we explore the association of pro-inflammatory conditions to CLP. By studying neural crest (NC) from mouse, Xenopus and humans, we show that CLP can be explained by a 2-hit model, where NC migration is impaired by a combination of genetic (CDH1 loss-of-function) and environmental (pro-inflammatory activation) factors, leading to CLP. Finally, using in vivo targeted methylation assays, we demonstrate that CDH1 hypermethylation is the major target of the pro-inflammatory response, and a direct regulator of E-cadherin levels and NC migration. These results unveil a gene-environment interaction during craniofacial development and provide a 2-hit mechanism to explain cleft lip/palate aetiology.

The Tip60/Ep400 chromatin remodeling complex impacts basic cellular functions in cranial neural crest-derived tissue during early orofacial development

The cranial neural crest plays a fundamental role in orofacial development and morphogenesis. Accordingly, mutations with impact on the cranial neural crest and its development lead to orofacial malformations such as cleft lip and palate. As a pluripotent and dynamic cell population, the cranial neural crest undergoes vast transcriptional and epigenomic alterations throughout the formation of facial structures pointing to an essential role of factors regulating chromatin state or transcription levels. Using CRISPR/Cas9-guided genome editing and conditional mutagenesis in the mouse, we here show that inactivation of Kat5 or Ep400 as the two essential enzymatic subunits of the Tip60/Ep400 chromatin remodeling complex severely affects carbohydrate and amino acid metabolism in cranial neural crest cells. The resulting decrease in protein synthesis, proliferation and survival leads to a drastic reduction of cranial neural crest cells early in fetal development and a loss of most facial structures in the absence of either protein. Following heterozygous loss of Kat5 in neural crest cells palatogenesis was impaired. These findings point to a decisive role of the Tip60/Ep400 chromatin remodeling complex in facial morphogenesis and lead us to conclude that the orofacial clefting observed in patients with heterozygous KAT5 missense mutations is at least in part due to disturbances in the cranial neural crest.

Trio-based GWAS identifies novel associations and subtype-specific risk factors for cleft palate

Orofacial clefts (OFCs) are the most common craniofacial birth defects and are often categorized into two etiologically distinct groups: cleft lip with or without cleft palate (CL/P) and isolated cleft palate (CP). CP is highly heritable, but there are still relatively few established genetic risk factors associated with its occurrence compared to CL/P. Historically, CP has been studied as a single phenotype despite manifesting across a spectrum of defects involving the hard and/or soft palate. We performed GWAS using transmission disequilibrium tests using 435 case-parent trios to evaluate broad risks for any cleft palate (ACP, n=435), as well as subtype-specific risks for any cleft soft palate (CSP, n=259) and any cleft hard palate (CHP, n=125). We identified a single genome-wide significant locus at 9q33.3 (lead SNP rs7035976, p=4.24×10 -8 ) associated with CHP. One gene at this locus, angiopoietin-like 2 ( ANGPTL2 ), plays a role in osteoblast differentiation. It is expressed in craniofacial tissue of human embryos, as well as in the developing mouse palatal shelves. We found 19 additional loci reaching suggestive significance (p<5×10 -6 ), of which only one overlapped between groups (chromosome 17q24.2, ACP and CSP). Odds ratios (ORs) for each of the 20 loci were most similar across all three groups for SNPs associated with the ACP group, but more distinct when comparing SNPs associated with either the CSP or CHP groups. We also found nominal evidence of replication (p<0.05) for 22 SNPs previously associated with cleft palate (including CL/P). Interestingly, most SNPs associated with CL/P cases were found to convey the opposite effect in those replicated in our dataset for CP only. Ours is the first study to evaluate CP risks in the context of its subtypes and we provide newly reported associations affecting the broad risk for CP as well as evidence of subtype-specific risks.

Association between variants around IRF6 and non-syndromic orofacial cleft in Western Han Chinese

OBJECTIVES

Considering limitations of previous studies and differences across populations and subtypes, this study aimed to identify new potential SNPs around IRF6 associated with non-syndromic orofacial cleft (NSOC) in Western Han Chinese.

MATERIALS AND METHODS

We recruited 376 NSOC case-parent trios, including 125 non-syndromic cleft lip only (NSCLO) trios, 151 non-syndromic cleft lip and palate (NSCLP) trios, and 100 non-syndromic cleft palate only (NSCPO) trios. Twenty-two single-nucleotide polymorphisms (SNPs) were genotyped using MassARRAY method. Hardy-Weinberg equilibrium test, allelic transmission disequilibrium test (TDT) analysis, sliding-window haplotype TDT analysis, and tests for parent-of-origin effect were performed using the PLINK software. Pairwise linkage disequilibrium (LD) was computed using the Haploview program.

RESULTS

In TDT analysis, allele A at rs17015217 (p = 0.00011, OR = 0.61 and 95% CI: 0.47-0.78) and allele T at rs12080691 (p = 0.00011, OR = 0.61 and 95% CI: 0.47-0.78) were under-transmitted among NSCLO trios but over-transmitted among NSCPO trios. Haplotypes showing evidence of under-transmission in NSCLO trios were over-transmitted in NSCPO trios. In tests for parent-of-origin effects, T allele at rs12080691 presented paternal under-transmission among NSCLO trios but over-transmission among NSCPO trios.

CONCLUSIONS

Allele A at rs17015217 and allele T at rs12080691 are associated with NSCLO and NSCPO with potential to have opposite effects on two subtypes in this sample from Western Han Chinese.

Concurrent de novo ZFHX4 variant and 16q24.1 deletion in a patient with orofacial clefting; a potential role of ZFHX4 and USP10

A girl with a unilateral cleft lip, alveolus and palate, tooth agenesis, and mild dysmorphic features, without a specific underlying syndrome diagnosis, was genotypically characterized and phenotypically described. Cleft gene panel analysis, single-nucleotide polymorphism (SNP) array, whole genome sequencing (WGS), whole exome sequencing, and quantitative PCR (Q-PCR) analysis were used as diagnostic tests. SNP array revealed a maternal deletion at 16q24.1, encompassing the cleft candidate gene USP10. WES revealed an additional de novo Loss-of-Function variant (p.(Asn838fs)) in the Zinc-Finger-Homeobox-4 (ZFHX4) gene. Q-PCR was performed to explore the effect of the ZFHX4 variant and the deletion in 16q24.1. The mRNA expression of a selection of putative target genes involved in orofacial clefting showed a lowered expression of USP10 (52%), CRISPLD2 (31%), and CRISPLD1 (1%) compared to the control. IRF6 showed no difference in gene expression. This case supports ZFHX4 as a novel cleft gene and suggests USP10 may contribute to the etiology of orofacial clefts in humans.

Understanding the distinction between cleft lip and cleft palate: a critical step for successful prenatal detection

PURPOSE OF REVIEW

Orofacial clefts (OCs) are among the most common congenital anomalies, however, prenatal detection of cleft palate without cleft lip (CP) remains low. CP is associated with a higher risk of associated structural anomalies, recurrence risk and genetic aberrations. There is opportunity to optimize prenatal diagnosis, counseling and diagnostic genetic testing for OCs.

RECENT FINDINGS

Improving prenatal diagnosis of CP requires understanding that embryologically, the secondary palate develops from the 6th to the 10th week and fuses with the primary palate by the 12th week. Multiple first, second and third trimester 2D ultrasonographic markers for OCs have been described including the maxillary gap, frontal space, maxilla-nasion-mandible angle, retronasal triangle, palatino-maxillary diameter, equal sign, nonvisualization or gap in the soft to hard palate interface and loss of the superimposed line. We discuss the technique, evidence and limitations of each.

SUMMARY

Prenatal detection of OC can be optimized by employing 2D sonographic markers. Prenatal detection of CP may be improved by recognizing its high association with retrognathia/micrognathia.

Rare genetic variants in SEC24D modify orofacial cleft phenotypes

As one of the most common structural birth defects, orofacial clefts (OFCs) have been studied for decades, and recent studies have demonstrated that there are genetic differences between the different phenotypic presentations of OFCs. However, the contribution of rare genetic variation genome-wide to different subtypes of OFCs has been understudied, with most studies focusing on common genetic variation or rare variation within targeted regions of the genome. Therefore, we used whole-genome sequencing data from the Gabriella Miller Kids First Pediatric Research Program to conduct a gene-based burden analysis to test for genetic modifiers of cleft lip (CL) vs cleft lip and palate (CLP). We found that there was a significantly increased burden of rare variants in SEC24D in CL cases compared to CLP cases (p=6.86×10-7). Of the 15 variants within SEC24D, 53.3% were synonymous, but overlapped a known craniofacial enhancer. We then tested whether these variants could alter predicted transcription factor binding sites (TFBS), and found that the rare alleles destroyed binding sites for 9 transcription factors (TFs), including Pax1 (p=0.0009), and created binding sites for 23 TFs, including Pax6 (p=6.12×10-5) and Pax9 (p= 0.0001), which are known to be involved in normal craniofacial development, suggesting a potential mechanism by which these synonymous variants could have a functional impact. Overall, this study demonstrates that rare genetic variation contributes to the phenotypic heterogeneity of OFCs and suggests that regulatory variation may also contribute and warrant further investigation in future studies of genetic variants controlling risk to OFC.

Seasonal, Geographic, and Ethnic Influence on the Prevalence of Orofacial Clefts in Kuwait: A Nationwide Study

OBJECTIVE

Accurate nationwide epidemiological evidence is vital to study the seasonal, geographic, and ethnic influence on the trends of orofacial cleft prevalence in Kuwait.

DESIGN

Data obtained from the National Center for Health Information and Ministry of Health Hospital digital records were reviewed retrospectively to identify patients with orofacial clefts (OFC) using the ICD-10 diagnostic codes. The Jonckheere-Terpstra test was used to assess the trend of birth prevalence across the different years. The associations of types of OFC with ethnic and geographic influences were tested with chi-square or Fisher's exact tests, while the strength of that association was tested with multi-nominal logistic regression.

RESULTS

Birth prevalence in Kuwait ranged from 0.75-2.55 per 1000 live births (0.73- 2.73 among Kuwaitis, 0.60-3.27 among non-Kuwaitis), with no statistically significant change observed during the past 28 years. The risk of unilateral cleft lip and palate was eight times higher during summer compared to Autumn, while the risk of cleft lip and palate remained lower during winter. Jahra (OR-7.76, CI- 1.51-39.80), Farwaneya (OR-6.65, CI- 1.34-33.06), and Hawalli (OR-6.72, CI- 1.26-35.98) governorates had higher odds of bilateral cleft lip when compared to Mubarak Alkabeer.

CONCLUSIONS

The study outcome is an indicator to improve patient care and customize healthcare infrastructure in the Ministry of Health. It also provides insight to develop projections of future needs. Future studies should focus on understanding the factors that might be a potential contributor to the seasonal change observed in the prevalence of OFC.

Identification of Novel Risk Variants of Non-Syndromic Cleft Palate by Targeted Gene Panel Sequencing

Non-syndromic cleft palate (ns-CP) has a genetically heterogeneous aetiology. Numerous studies have suggested a crucial role of rare coding variants in characterizing the unrevealed component of genetic variation in ns-CP called the "missing heritability". Therefore, this study aimed to detect low-frequency variants that are implicated in ns-CP aetiology in the Polish population. For this purpose, coding regions of 423 genes associated with orofacial cleft anomalies and/or involved with facial development were screened in 38 ns-CP patients using the next-generation sequencing technology. After multistage selection and prioritisation, eight novel and four known rare variants that may influence an individual's risk of ns-CP were identified. Among detected alternations, seven were located in novel candidate genes for ns-CP, including COL17A1 (c.2435-1G>A), DLG1 (c.1586G>C, p.Glu562Asp), NHS (c.568G>C, p.Val190Leu-de novo variant), NOTCH2 (c.1997A>G, p.Tyr666Cys), TBX18 (c.647A>T, p.His225Leu), VAX1 (c.400G>A, p.Ala134Thr) and WNT5B (c.716G>T, p.Arg239Leu). The remaining risk variants were identified within genes previously linked to ns-CP, confirming their contribution to this anomaly. This list included ARHGAP29 (c.1706G>A, p.Arg569Gln), FLNB (c.3605A>G, Tyr1202Cys), IRF6 (224A>G, p.Asp75Gly-de novo variant), LRP6 (c.481C>A, p.Pro161Thr) and TP63 (c.353A>T, p.Asn118Ile). In summary, this study provides further insights into the genetic components contributing to ns-CP aetiology and identifies novel susceptibility genes for this craniofacial anomaly.

Morphometric analysis of the size-adjusted linear dimensions of the skull landmarks revealed craniofacial dysmorphology in Mid1-cKO mice

BACKGROUND

The early craniofacial development is a highly coordinated process involving neural crest cell migration, proliferation, epithelial apoptosis, and epithelial-mesenchymal transition (EMT). Both genetic defects and environmental factors can affect these processes and result in orofacial clefts. Mutations in MID1 gene cause X-linked Opitz Syndrome (OS), which is a congenital malformation characterized by craniofacial defects including cleft lip/palate (CLP). Previous studies demonstrated impaired neurological structure and function in Mid1 knockout mice, while no CLP was observed. However, given the highly variable severities of the facial manifestations observed in OS patients within the same family carrying identical genetic defects, subtle craniofacial malformations in Mid1 knockout mice could be overlooked in these studies. Therefore, we propose that a detailed morphometric analysis should be necessary to reveal mild craniofacial dysmorphologies that reflect the similar developmental defects seen in OS patients.

RESULTS

In this research, morphometric study of the P0 male Mid1-cKO mice were performed using Procrustes superimposition as well as EMDA analysis of the size-adjusted three-dimensional coordinates of 105 skull landmarks, which were collected on the bone surface reconstructed using microcomputed tomographic images. Our results revealed the craniofacial deformation such as the increased dimension of the frontal and nasal bone in Mid1-cKO mice, in line with the most prominent facial features such as hypertelorism, prominent forehead, broad and/or high nasal bridge seen in OS patients.

CONCLUSION

 While been extensively used in evolutionary biology and anthropology in the last decades, geometric morphometric analysis was much less used in developmental biology. Given the high interspecies variances in facial anatomy, the work presented in this research suggested the advantages of morphometric analysis in characterizing animal models of craniofacial developmental defects to reveal phenotypic variations and the underlining pathogenesis.

The IRF6 AP-2α binding site polymorphism relate to the severity of non-syndromic orofacial cleft of Indonesian patients

BACKGROUND

IRF6 AP-2α binding site polymorphism is known as IRF6 rs642961. It has been associated with a nonsyndromic orofacial cleft (NS OFC). This study aimed to determine the IRF6 rs642961 as a risk factor associated with NS OFC and its phenotypes.

METHODS

The case-control design used for 264 subjects consists of 158 NS CLP subjects (42 CU CLP, 34 CB CLP, 33 CLO, 49 CPOs) and 106 healthy controls. The DNA is extracted from venous blood. The segment of IRF6 rs642961 amplified by polymerase chain reaction (PCR) followed by restriction fragment length of polymorphisms (RFLPs) used the MspI digestion enzyme. The qPCR method to identify the mRNA expression levels of the IRF6 gene rs642961 was analyzed by the Livak method.

RESULTS

The study results show that in NS CB CLP phenotype as the most severe phenotype of NS OFC, the Odds Ratio (OR) of A mutant allele was 5.094 (CI=1.456-17.820; P=0.011) and the OR of AA homozygous mutant genotype was 13.481 (CI=2.648-68.635; P=0.001). There are different levels of mRNA expression changes from NS OFC and its phenotypes. It is substantial among the 2^-ΔΔCt and the group of AA, GA, and GG genotypes (P<0.05); in the NS CPO phenotype, it shows IRF6 mRNA under-expression in GA, AA genotypes while in other phenotypes it shows IRF6 mRNA overexpression.

CONCLUSIONS

The IRF6 AP-2α binding site polymorphism is strongly associated with the severity of NS OFC, and this polymorphism has a functional role in affecting IRF6 mRNA expression that is variable in each phenotype.

Surgical Strategy for the Treatment of Facial Clefts

Craniofacial clefts have an incidence of 1/700 [...]

Maternal Transmission of the PAX7 Single Nucleotide Polymorphisms among Indian Cleft Trios

Cleft lip and/or cleft palate (CL/P) is one of the most common congenital anomalies of the human face with a complex etiology involving multiple genetic and environmental factors. Several studies have shown the association of the paired box 7 ( PAX7 ) gene with CL/P in different populations worldwide. However, the current literature reveals no reported case-parent trio studies to evaluate the association between the PAX7 gene and the risk of nonsyndromic cleft lip and/or palate (NSCL/P) in the Indian population. Hence, the purpose of this study was to assess the PAX7 gene single nucleotide polymorphisms (SNPs) in the etiology of NSCL/P among the Indian cleft trios. Forty Indian case-parent trios of NSCL/P were included. The cases and their parents' genomic DNA were extracted. The SNPs rs9439714, rs1339062, rs6695765, rs742071, and rs618941of the PAX7 gene were genotyped using the Agena Bio MassARRAY analysis. The allelic transmission disequilibrium test was performed using PLINK software while pair-wise linkage disequilibrium by the Haploview program. The SNP rs9439714 showed evidence of association ( p -value = 0.02, odds ratio = 3) with NSCL/P. Considering the parent-of-origin effects, the SNPs rs9439714 and rs618941 showed an excess maternal transmission of allele C at rs9439714 ( p -value = 0.05) and G allele at rs618941 ( p -value = 0.04). The results of the present study suggested that the SNPs rs9439714 and rs618941 showed an excess maternal transmission of alleles suggestive of the possible role of the PAX7 gene involvement in the etiology of NSCL/P in the Indian population.

Genome-wide analysis of copy-number variation in humans with cleft lip and/or cleft palate identifies COBLL1, RIC1, and ARHGEF38 as clefting genes

Cleft lip with or without cleft palate (CL/P) is a common birth defect with a complex, heterogeneous etiology. It is well established that common and rare sequence variants contribute to the formation of CL/P, but the contribution of copy-number variants (CNVs) to cleft formation remains relatively understudied. To fill this knowledge gap, we conducted a large-scale comparative analysis of genome-wide CNV profiles of 869 individuals from the Philippines and 233 individuals of European ancestry with CL/P with three primary goals: first, to evaluate whether differences in CNV number, amount of genomic content, or amount of coding genomic content existed within clefting subtypes; second, to assess whether CNVs in our cohort overlapped with known Mendelian clefting loci; and third, to identify unestablished Mendelian clefting genes. Significant differences in CNVs across cleft types or in individuals with non-syndromic versus syndromic clefts were not observed; however, several CNVs in our cohort overlapped with known syndromic and non-syndromic Mendelian clefting loci. Moreover, employing a filtering strategy relying on population genetics data that rare variants are on the whole more deleterious than common variants, we identify several CNV-associated gene losses likely driving non-syndromic clefting phenotypes. By prioritizing genes deleted at a rare frequency across multiple individuals with clefts yet enriched in our cohort of individuals with clefts compared to control subjects, we identify COBLL1, RIC1, and ARHGEF38 as clefting genes. CRISPR-Cas9 mutagenesis of these genes in Xenopus laevis and Danio rerio yielded craniofacial dysmorphologies, including clefts analogous to those seen in human clefting disorders.

Recent Advances in Nasoalveolar Molding Therapy Using 3D Technology

Presurgical Nasoalveolar Molding (NAM) is an adjunctive treatment modality designed to reorient misaligned tissue structures and nasal cartilage in cleft lip and/or palate (CL/P) patients. Recent advances in NAM therapy focus on modifications to the intraoral molding plate or nasal stent intended to improve treatment outcomes, ease of use, compliance, and cost-effectiveness. Notably, 3D technological advancements have been employed to design NAM devices more efficiently and create objective, standardized means of measuring progressive morphological changes during therapy. These advances are designed to incorporate 3D technology in the treatment of cleft lip and/or palate to render it more precise, accurate, and time-efficient.

Orofacial clefts lead to increased pro-inflammatory cytokine levels on neonatal oral mucosa

Orofacial clefts (OFC) are frequent congenital malformations characterized by insufficient separation of oral and nasal cavities and require presurgical infant orthopedics and surgical interventions within the first year of life. Wound healing disorders and higher prevalence of gingivitis and plaque levels are well-known challenges in treatment of children with OFC. However, oral inflammatory mediators were not investigated after birth using non-invasive sampling methods so far. In order to investigate the impact of OFC on oral cytokine levels, we collected tongue smear samples from 15 neonates with OFC and 17 control neonates at two time points (T), T0 at first consultation after birth, and T1, 4 to 5 weeks later. The samples were analyzed using multiplex immunoassay. Overall, we found significantly increased cytokine levels (TNF, IL-1β/-2/-6/-8/-10) in tongue smear samples from neonates with OFC compared to controls, especially at T0. The increase was even more pronounced in neonates with a higher cleft severity. Further, we detected a significant positive correlation between cleft severity score and distinct pro-inflammatory mediators (GM-CSF, IL-1β, IL-6, IL-8) at T0. Further, we found that breast-milk (bottle) feeding was associated with lower levels of pro-inflammatory cytokines (IL-6/-8) in neonates with OFC compared to formula-fed neonates. Our study demonstrated that neonates with OFC, especially with high cleft severity, are characterized by markedly increased inflammatory mediators in tongue smear samples within the first weeks of life potentially presenting a risk for oral inflammatory diseases. Therefore, an inflammatory monitoring of neonates with (severe) OFC and the encouragement of mother to breast-milk (bottle) feed might be advisable after birth and/or prior to cleft surgery.

A392V and R945X mutations cause orofacial clefts via impairing PTCH1 function

The Hedgehog (HH) signaling plays key roles in embryogenesis and organogenesis, and its dysfunction causes a variety of human birth defects. Orofacial cleft (OFC) is one of the most common congenital craniofacial defects, and its etiology is closely related to mutations in multiple components in the HH pathway, including the PTCH1 receptor. A quantity of PTCH1 variants have been associated with OFC, but the pathogenicity and underlying mechanism of these variants have not been functionally validated. In our previous studies, we identified two PTCH1 variants (A392V and R945X) in two families with hereditary OFC. Here we explore the functional consequences of these two variants. In zebrafish embryos, microinjection of wild type PTCH1 mRNA causes curved body axis and craniofacial anomalies. In contrast, microinjection of A392V and R945X PTCH1 mRNAs results in much milder phenotypes, suggesting these two variants are loss-of-function mutations. In mammalian cells, A392V and R945X mutations reverse the inhibitory effect of PTCH1 on HH signaling. Biochemically, the two mutants PTCH1 show lower expression levels and shortened half-life, indicting these mutations decrease the stability of PTCH1. A392V and R945X mutations also appear to cause PTCH1 to localize away from vesicles. Taken together, our findings indicate that A392V and R945X variants are loss-of-function mutations that disrupt the function of PTCH1 and thus cause dysregulation of HH signaling, leading to the pathogenesis of OFC.