FGFR1 variants contributed to families with tooth agenesis.

BACKGROUND: Tooth agenesis is a common dental anomaly that can substantially affect both the ability to chew and the esthetic appearance of patients. This study aims to identify possible genetic factors that underlie various forms of tooth agenesis and to investigate the possible molecular mechanisms through which human dental pulp stem cells may play a role in this condition. RESULTS: Using whole-exome sequencing of a Han Chinese family with non-syndromic tooth agenesis, a rare mutation in FGFR1 (NM_001174063.2: c.103G > A, p.Gly35Arg) was identified as causative and confirmed by Sanger sequencing. Via GeneMatcher, another family with a known variant (NM_001174063.2: c.1859G > A, p.Arg620Gln) was identified and diagnosed with tooth agenesis and a rare genetic disorder with considerable intrafamilial variability. Fgfr1 is enriched in the ectoderm during early embryonic development of mice and showed sustained low expression during normal embryonic development of Xenopus laevis frogs. Functional studies of the highly conserved missense variant c.103G > A showed deleterious effects. FGFR1 (c.103G > A) was overexpressed compared to wildtype and promoted proliferation while inhibiting apoptosis in HEK293 and human dental pulp stem cells. Moreover, the c.103G > A variant was found to suppress the epithelial-mesenchymal transition. The variant could downregulate ID4 expression and deactivate the TGF-beta signaling pathway by promoting the expression of SMAD6 and SMAD7. CONCLUSION: Our research broadens the mutation spectrum associated with tooth agenesis and enhances understanding of the underlying disease mechanisms of this condition.

Eight EDA mutations in Chinese patients with tooth agenesis and genotype-phenotype analysis.

OBJECTIVE: Tooth agenesis is a common craniofacial malformation, which is often associated with gene mutations. The purpose of this research was to investigate and uncover ectodysplasin A (EDA) gene variants in eight Chinese families affected with tooth agenesis. METHODS: Genomic DNA was extracted from tooth agenesis families and sequenced using whole-exome sequencing. The expression of ectodysplasin A1 (EDA1) protein was studied by western blot, binding activity with receptor was tested by pull-down and the NF-κB transcriptional activity was analyzed by Dual luciferase assay. RESULTS: Eight EDA missense variants were discovered, of which two (c.T812C, c.A1073G) were novel. The bioinformatics analysis indicated that these variants might be pathogenic. The tertiary structure analysis revealed that these eight variants could cause structural damage to EDA proteins. In vitro functional studies demonstrated that the variants greatly affect protein stability or impair the EDA-EDAR interaction; thereby significantly affecting the downstream NF-κb transcriptional activity. In addition, we summarized the genotype-phenotype correlation caused by EDA variants and found that EDA mutations leading to NSTA are mostly missense mutations located in the TNF domain. CONCLUSION: Our results broaden the variant spectrum of the EDA gene associated with tooth agenesis and provide valuable information for future genetic counseling.

Identification of a novel de novo mutation in SOX4 for syndromic tooth agenesis.

OBJECTIVES: Coffin-Siris Syndrome (CSS) is a congenital disorder characterized by delayed growth, dysmorphic facial features, hypoplastic nails and phalanges of the fifth digit, and dental abnormalities. Tooth agenesis has been reported in CSS patients, but the mechanisms regulating this syndromic tooth agenesis remain largely unknown. This study aims to identify the pathogenic mutation of CSS presenting tooth genesis and explore potential regulatory mechanisms. MATERIALS AND METHODS: We utilized whole-exome sequencing to identify variants in a CSS patient, followed by Sanger validation. In silico analysis including conservation analysis, pathogenicity predictions, and 3D structural assessments were carried out. Additionally, single-cell RNA sequencing and fluorescence in situ hybridization (FISH) were applied to explore the spatio-temporal expression of Sox4 expression during murine tooth development. Weighted Gene Co-expression Network Analysis (WGCNA) was employed to examine the functional role of SOX4. RESULTS: A novel de novo SOX4 missense mutation (c.1255C > G, p.Leu419Val) was identified in a Chinese CSS patient exhibiting tooth agenesis. Single-cell RNA sequencing and FISH further verified high expression of Sox4 during murine tooth development, and WGCNA confirmed its central role in tooth development pathways. Enriched functions included cell-substrate junctions, focal adhesion, and RNA splicing. CONCLUSIONS: Our findings link a novel SOX4 mutation to syndromic tooth agenesis in CSS. This is the first report of SOX4 missense mutation causing syndromic tooth agenesis. CLINICAL RELEVANCE: This study not only enhances our understanding of the pathogenic mutation for syndromic tooth agenesis but also provides genetic diagnosis and potential therapeutic insights for syndromic tooth agenesis.

Ectopic Activation of Fgf8 in Dental Mesenchyme Causes Incisor Agenesis and Molar Microdontia.

Putatively, tooth agenesis was attributed to the initiation failure of tooth germs, though little is known about the histological and molecular alterations. To address if constitutively active FGF signaling is associated with tooth agenesis, we activated Fgf8 in dental mesenchyme with Osr-cre knock-in allele in mice (Osr2-creKI; Rosa26R-Fgf8) and found incisor agenesis and molar microdontia. The cell survival assay showed tremendous apoptosis in both the Osr2-creKI; Rosa26R-Fgf8 incisor epithelium and mesenchyme, which initiated incisor regression from cap stage. In situ hybridization displayed vanished Shh transcription, and immunostaining exhibited reduced Runx2 expression and enlarged mesenchymal Lef1 domain in Osr2-creKI; Rosa26R-Fgf8 incisors, both of which were suggested to enhance apoptosis. In contrast, Osr2-creKI; Rosa26R-Fgf8 molar germs displayed mildly suppressed Shh transcription, and the increased expression of Ectodin, Runx2 and Lef1. Although mildly smaller than WT controls prenatally, the Osr2-creKI; Rosa26R-Fgf8 molar germs produced a miniature tooth with impaired mineralization after a 6-week sub-renal culture. Intriguingly, the implanted Osr2-creKI; Rosa26R-Fgf8 molar germs exhibited delayed odontoblast differentiation and accelerated ameloblast maturation. Collectively, the ectopically activated Fgf8 in dental mesenchyme caused incisor agenesis by triggering incisor regression and postnatal molar microdontia. Our findings reported tooth agenesis resulting from the regression from the early bell stage and implicated a correlation between tooth agenesis and microdontia.

Treatment strategy for patient with non-syndromic tooth agenesis: a case report and literature review.

BACKGROUND: Non-syndromic tooth agenesis (NSTA) is a type of ectodermal dysplasia (ED) in which patients with non-syndromic oligodontia may only affect teeth. No pathological findings were found in other tissues of the ectodermal. Herein, we report a case of a NSTA patient with severe dental anxiety and poor oral health. CASE PRESENTATION: A 5-year-old boy without systemic diseases presented as a patient with oligodontia, extensive caries, and periapical periodontitis. Molecular genetic analysis found a mutation in the Ectodysplasin A (EDA) gene, confirming the diagnosis of NSTA. CONCLUSION: Tooth agenesis (TA) is the most common ectodermal developmental abnormality in humans. Non-syndromic oligodontia patients often seek treatment in the department of stomatology. Because of their complex oral conditions, these patients should be provided with a systematic and personalized treatment plan.

Compound heterozygous WNT10A missense variations exacerbated the tooth agenesis caused by hypohidrotic ectodermal dysplasia.

BACKGROUND: The aim of this study was to analyse the differences in the phenotypes of missing teeth between a pair of brothers with hypohidrotic ectodermal dysplasia (HED) and to investigate the underlying mechanism by comparing the mutated gene loci between the brothers with whole-exome sequencing. METHODS: The clinical data of the patients and their mother were collected, and genomic DNA was extracted from peripheral blood samples. By Whole-exome sequencing filtered for a minor allele frequency (MAF) ≤0.05 non-synonymous single-nucleotide variations and insertions/deletions variations in genes previously associated with tooth agenesis, and variations considered as potentially pathogenic were assessed by SIFT, Polyphen-2, CADD and ACMG. Sanger sequencing was performed to detect gene variations. The secondary and tertiary structures of the mutated proteins were predicted by PsiPred 4.0 and AlphaFold 2. RESULTS: Both brothers were clinically diagnosed with HED, but the younger brother had more teeth than the elder brother. An EDA variation (c.878 T > G) was identified in both brothers. Additionally, compound heterozygous variations of WNT10A (c.511C > T and c.637G > A) were identified in the elder brother. Digenic variations in EDA (c.878 T > G) and WNT10A (c.511C > T and c.637G > A) in the same patient have not been reported previously. The secondary structure of the variant WNT10A protein showed changes in the number and position of α-helices and ß-folds compared to the wild-type protein. The tertiary structure of the WNT10A variant and molecular simulation docking showed that the site and direction where WNT10A binds to FZD5 was changed. CONCLUSIONS: Compound heterozygous WNT10A missense variations may exacerbate the number of missing teeth in HED caused by EDA variation.

An in vitro and computational validation of a novel loss-of-functional mutation in PAX9 associated with non-syndromic tooth agenesis.

Congenital tooth agenesis (CTA) is one of the most common craniofacial anomalies. Its frequency varies among different population depending upon the genetic heterogeneity. CTA could be of familial or sporadic and syndromic or non-syndromic. Five major genes are found to be associated with non-syndromic CTA, namely PAX9, MSX1, EDA1, AXIN2, and WNT10A. Very few studies have been carried out so far on CTA on this Indian population making this study unique and important. This study was initiated to identify potential pathogenic variant associated with congenital tooth agenesis in an India family with molar tooth agenesis. CTA was investigated and a novel c.336C > G variation was identified in the exon 3 of PAX9, leading to substitution of evolutionary conserved Cys with Trp at 112th amino acid position located at the functionally significant DNA-binding paired domain region. Functional analysis revealed that p.Cys112Trp mutation did not prevent the nuclear localization although mutant protein had higher cytoplasmic retention. EMSA using e5 probe revealed that mutant protein was unable to bind with the paired-domain-binding site. Subsequently, GST pull-down assay revealed lower binding activity of the mutant protein with its known interactor MSX1. These in vitro results were consistent with the computational results. The in vitro and computational observations altogether suggest that c.336C > G (p.Cys112Trp) variation leads to loss of function of PAX9 leading to CTA in this family.

Gastrointestinal symptoms in patients with isolated oligodontia and a Wnt gene mutation.

OBJECTIVE: Since Wnt signaling plays an important role in both tooth agenesis and altered intestine homeostasis, the aim was to compare gastrointestinal symptoms in patients with isolated oligodontia caused by a Wnt pathway gene mutation and controls. METHODS: A case-control study was designed to compare self-reported gastrointestinal symptoms among patients with isolated oligodontia, caused by a Wnt signaling gene mutation, and fully dentate controls. The Gastrointestinal Symptom Rating Scale (GSRS) was used to assess gastrointestinal symptoms. Prevalence and severity of gastrointestinal symptoms among patients and age- and gender-matched controls were evaluated. RESULTS: Twenty patients with isolated oligodontia and a pathogenic variant in the wnt pathway genes WNT10A, LRP6, or PAX9 participated. The prevalence of gastrointestinal symptoms was higher in the oligodontia patients compared to their controls (Χ2 (1) = 87.33, p = .008). Mean GSRS total scores (p = .011) and domain scores for "abdominal pain" (p = .022), "reflux" (p = .003) and constipation (p = .030) were higher for these oligodontia patients compared to their controls. CONCLUSION: Gastrointestinal symptoms are more prevalent and more severe in patients with isolated oligodontia and a deficiency in a Wnt pathway-related gene, when compared to controls without tooth agenesis.

A Genome-wide association study of premolar agenesis in a chinese population.

OBJECTIVE: Premolar agenesis is a common subtype of tooth agenesis. Although a genome-wide study (GWAS) has identified some variants involved in tooth agenesis in Europeans, the genetic mutation related to premolar agenesis in the Chinese population remains unclear. MATERIALS AND METHODS: We present a GWAS in 218 premolar agenesis cases and 1,222 controls using the Illumina Infinium® Global Screening Array. 5,585,618 single nucleotide polymorphisms (SNPs) were used for tests of associations with premolar agenesis. RESULTS: Four independent SNPs on chromosome 2 were identified as susceptibility loci, including rs147680216, rs79743039, rs60540881, and rs6738629. The genome-wide significant SNP rs147680216 (p = 6.09 × 10-9 ) was predicted to change the structure of the WNT10A protein and interact with hedgehog signaling pathway components. Meta-analysis showed that the rs147680216 A allele significantly increased the risk of tooth agenesis (p = 0.000). The other three SNPs with nominal significance are novel susceptibility loci. Of them, rs6738629 (p = 5.40 × 10-6 ) acts as a potential transcriptional regulator of GCC2, a gene playing a putative role in dental and craniofacial development. CONCLUSION: Our GWAS indicates that rs147680216 and additional three novel susceptibility loci on chromosome 2 are associated with the risk of premolar agenesis in the Chinese population.

Gene mutations and chromosomal abnormalities in syndromes with tooth agenesis.

This study aims to review the pathogenic mechanisms and clinical manifestations in syndromes with tooth agenesis (TA). Online Mendelian Inheritance in Man and PubMed databases were searched for a comprehensive review. Previous publications reported complicated aetiologies of syndromic TA. Gene mutations in conserved signalling pathways (WNT, EDA, SHH, FGF, and TGF-ß/BMP) and crucial molecules (PAX9, PIXT2, IRF6, the p53 family, and subunits of RNA polymerase III) are the main causes of syndromic TA. In the process of odontogenesis, antagonistic or synergistic interactions are demonstrated in patients and murine models. Mutations in some genes (WNT10A, WNT10B, AXIN2, ANTXR1, MSX1, EDA, EDAR, and EDARADD) can result in both syndromic and isolated TA. In addition, chromosomal anomalies are also responsible for syndromic TA (Down syndrome, Wolf-Hirschhorn syndrome, Williams syndrome, and Pierre Robin sequence). The causes and manifestations of syndromic TA are highly complex, and this constitutes a clinical challenge. Mutations in signalling pathways and crucial molecules as well as chromosomal anomalies are responsible for syndromic TA. And there are overlaps between the causative genes of syndromic and isolated TA.

Detection of novel variant and functional study in a Chinese family with nonsyndromic oligodontia.

OBJECTIVES: To investigate the pathogenic gene of a patient with nonsyndromic oligodontia, and analyze its possible pathogenic mechanism. SUBJECTS AND METHODS: The variant was detected by whole exome sequencing (WES) and Sanger sequencing in a family with oligodontia. Bioinformatic and structural analyses were used to analyze variant. Functional studies including western blotting and immunofluorescent analyses and luciferase reporter assay were conducted to explore the functional effects. RESULTS: We identified a novel frameshift variant of PAX9 (c.491-510delGCCCT-ATCACGGCGGCGGCC, p.P165Qfs*145) outside the DNA-binding domain causing an autosomal-dominant nonsyndromic oligodontia in a Chinese family. Bioinformatic and structural analyses revealed that the variant is pathogenic and conserved evolutionarily, and the changes might affect protein stability or folding. Functional studies demonstrate dramatically reduced ability in activating transcription activity of BMP4 promoter and a marked decrease in protein production, as evaluated by western blotting and immunofluorescent analyses. CONCLUSIONS: We found a novel frameshift variant of PAX9 causing nonsyndromic oligodontia in a Chinese family. Our findings indicate that frameshift variants cause loss of function of PAX9 protein during the patterning of the dentition and the subsequent tooth agenesis, providing new molecular insights into the role of frameshift variant of PAX9 and broaden the pathogenic spectrum of PAX9 variants.

MSX1 involved selective tooth agenesis and abnormal labial frenum, pedigree, and retrospective study.

OBJECTIVE: Muscle segment homeobox gene 1 (MSX1) is widely expressed in craniofacial development and tooth formation. The aim of this study was to report a novel MSX1 mutation in a Chinese family with selective tooth agenesis and abnormal median maxillary labial frenum (MMLF). MATERIALS AND METHODS: Mutation analysis was carried out by whole exome sequencing. The pMD18-T vector was used to verify the mutations. PubMed and Human Gene Mutation Database were searched to analyze the relationship between the mutations in MSX1 and related phenotypes. RESULTS: A novel heterozygous mutation (c.75delG) in MSX1 was detected in the proband and her mother. They presented as oligodontia and lower attached hypertrophy median maxillary labial frenum. 60 MSX1 mutations from 39 reports did not declare malformed MMLF except our cases. Meanwhile, we found that the types and sites of MSX1 mutations may affect the selectivity of tooth agenesis and orofacial cleft. CONCLUSION: This study suggests malformed MMLF as a new phenotype of MSX1 mutation and a specific relationship between MSX1 genotype and phenotype.

Craniofacial and dental features of Axenfeld-Rieger syndrome patients with PITX2 mutations.

We aimed to characterize the genetic basis and craniofacial and dental features of Finnish patients with Axenfeld-Rieger syndrome (ARS). Mutational analyses of seven patients in five families were performed by sequencing or comparative genomic hybridization. Phenotypic analysis was based on both clinical and radiographic examinations, as well as on medical data. Lateral cephalometric radiographs of five patients were analysed using Viewbox 3.1-Cephalometric Software. The cephalometric values were compared to Finnish population-standard values of the same age and gender. Two frameshift mutations and three whole gene deletions were detected in five families. Class III skeletal relationship with retrognathic maxilla and mildly retrognathic mandible were detected in all five patients studied. Significant differences compared with the control values were in SNA (P = .0014), ANB (P = .0043) and SNB angles (P = .013). Five patients had anterior crossbite. Six patients showed tooth agenesis. The average number of missing teeth (third molars excluded) was 9 (range 0-15). The tooth agenesis rate was 52% in maxilla and 26% in mandible. Maxillary central and lateral permanent incisors were most often missing (rate 71% equally) while no one lacked canines or first molars in mandible. Two patients had a supernumerary mandibular permanent incisor. Six patients had either taurodontic and/or single-rooted molars. Our results suggest that class III skeletal relationship with maxillary and mandibular retrognathism, anterior crossbite, maxillary incisor agenesis and taurodontic, even pyramidal, roots are common determinants of ARS caused by PITX2 mutations.

The phenotype and genotype of PAX9 mutations causing tooth agenesis.

OBJECTIVES: The purpose of this study was to identify associations between PAX9 mutations and clinical features of non-syndromic tooth agenesis patients. MATERIALS AND METHODS: Non-syndromic tooth agenesis patients were found to have mutations by whole exome sequencing (WES). Additionally, conservation analysis and three-dimensional structure prediction were also applied to identify mutated proteins. RESULTS: Eight non-syndromic tooth agenesis probands were identified with PAX9 mutations (c.C112T; C.131_134del; c.G151A; c.189delG; c.305delT; c.C365A; c.394delG; c.A679C). All of the probands were missing more than six teeth (oligodontia). The mutations (c.131_134del,p.R44fs; c.189delG,p.T63fs; c.305delT,p.I102fs and c.394delG,p.G123fs) caused premature termination of the PAX9 protein. The c.C112T(p.R38X) mutation created a truncated protein. Bioinformatic prediction demonstrated that the three missense mutations change the PAX9 structure suggesting the corresponding functional impairments. CONCLUSIONS: We reported that eight mutations of PAX9 caused non-syndromic tooth agenesis and analyzed the relationship between PAX9 mutations and non-syndromic tooth agenesis. CLINICAL RELEVANCE: Our study revealed that PAX9 mutations might be the mutations most associated with non-syndromic tooth agenesis in humans, which greatly broadened the mutation spectrum of PAX9-related non-syndromic tooth agenesis.

Maxillary lateral incisor agenesis is associated with maxillary form: a geometric morphometric analysis.

BACKGROUND AND OBJECTIVE: Agenesis of the maxillary lateral incisor occurs in up to 4% of all individuals and requires multidisciplinary treatment. Its developmental origins, however, are not fully understood. Earlier studies documented genetic factors contributing to agenesis but also an association with craniofacial morphology. In this study, we assessed the association between maxillary morphology and lateral incisor agenesis by a geometric morphometric approach to disentangle the roles of developmental plasticity and genetic factors. MATERIALS AND METHODS: We quantified the maxillary alveolar ridge by 19 two-dimensional landmarks on cross-sectional images of 101 computed tomography scans. We compared the shape and size of the alveolar ridge across patients with unilateral or bilateral agenesis of maxillary lateral incisors and patients with extracted or in situ incisors. RESULTS: The maxillary alveolar ridge was clearly narrower in patients with agenesis or an extracted incisor compared to the control group, whereas the contralateral side of the unilateral agenesis had an intermediate width. Despite massive individual variation, the ventral curvature of the alveolar ridge was, on average, more pronounced in the bilateral agenesis group compared to unilateral agenesis and tooth extraction. CONCLUSIONS: This suggests that pleiotropic genetic and epigenetic factors influence both tooth development and cranial growth, but an inappropriately sized or shaped alveolar process may also inhibit normal formation or development of the tooth bud, thus leading to dental agenesis. CLINICAL RELEVANCE: Our results indicate that bilateral agenesis of the lateral incisor tends to be associated with a higher need of bone augmentation prior to implant placement than unilateral agenesis.

BMPR2 Variants Underlie Nonsyndromic Oligodontia.

Oligodontia manifests as a congenital reduction in the number of permanent teeth. Despite the major efforts that have been made, the genetic etiology of oligodontia remains largely unknown. Bone morphogenetic protein receptor type 2 (BMPR2) variants have been associated with pulmonary arterial hypertension (PAH). However, the genetic significance of BMPR2 in oligodontia has not been previously reported. In the present study, we identified a novel heterozygous variant (c.814C > T; p.Arg272Cys) of BMPR2 in a family with nonsyndromic oligodontia by performing whole-exome sequencing. In addition, we identified two additional heterozygous variants (c.1042G > A; p.Val348Ile and c.1429A > G; p.Lys477Glu) among a cohort of 130 unrelated individuals with nonsyndromic oligodontia by performing Sanger sequencing. Functional analysis demonstrated that the activities of phospho-SMAD1/5/8 were significantly inhibited in BMPR2-knockout 293T cells transfected with variant-expressing plasmids, and were significantly lower in BMPR2 heterozygosity simulation groups than in the wild-type group, indicating that haploinsufficiency may represent the genetic mechanism. RNAscope in situ hybridization revealed that BMPR2 transcripts were highly expressed in the dental papilla and adjacent inner enamel epithelium in mice tooth germs, suggesting that BMPR2 may play important roles in tooth development. Our findings broaden the genetic spectrum of oligodontia and provide clinical and genetic evidence supporting the importance of BMPR2 in nonsyndromic oligodontia.

Genetic/Protein Association of Atopic Dermatitis and Tooth Agenesis.

Atopic dermatitis and abnormalities in tooth development (including hypomineralization, hypodontia and microdontia) have been observed to co-occur in some patients. A common pathogenesis pathway that involves genes and protein interactions has been hypothesized. This review aims to first provide a description of the key gene mutations and signaling pathways associated with atopic dermatitis and tooth agenesis (i.e., the absence of teeth due to developmental failure) and identify the possible association between the two diseases. Second, utilizing a list of genes most commonly associated with the two diseases, we conducted a protein-protein network interaction analysis using the STRING database and identified a novel association between the Wnt/ß-catenin signaling pathway (major pathway responsible for TA) and desmosomal proteins (component of skin barrier that affect the pathogenesis of AD). Further investigation into the mechanisms that may drive their co-occurrence and underlie the development of the two diseases is warranted.

Rare and Multiple Hypodontia in Van der Woude Syndrome: Case Report.

Van der Woude syndrome (VWS) is a rare syndrome of genetic etiology, commonly occasioned by mutations in the IRF6 gene and that causes disorders in craniofacial development. VWS is characterized by the presence of paramedian fistulas in the lower lip and cleft lip and / or cleft palate. Although some dental phenotypes have been reported in this syndrome, multiple and rare hypodontias were not described. Through this case report, we present a case of Van der Woude Syndrome (VWS) with rare and multiple hypodontia in which clinical data and radiographic exams were evaluated. The patient presented hypodontia of eight permanent teeth (lateral incisors, second premolars and second molars). So, when the dentist recognizes multiple and/or rare hypodontias, for an accurate diagnosis, detailed examination of the lower lip is indicated, as well as a survey of the family history and referral for genetic counseling, since the syndrome presents high penetrance. The patient is expected to be rehabilitated to have a good quality of life. Rehabilitation in these cases requires alveolar bone graft, orthodontics and prosthesis to replace missing teeth.

Identification of copy neutral loss of heterozygosity on chromosomes 1p, 1q, and 6p among nonsyndromic cleft lip and/or without cleft palate with hypodontia.

BACKGROUND: Nonsyndromic cleft lip and/or without cleft palate (NSCL/P) with or without hypodontia is a common developmental aberration in humans and animals. This study aimed to identify the loss of heterozygosity (LOH) involved in hypodontia and NSCL/P pathogenesis. METHODS: This is a cross-sectional study that conducted genome-wide copy number analysis using CytoScan 750K array on salivary samples from Malay subjects with NSCL/P with or without hypodontia aged 7-13 years. To confirm the significant results, simple logistic regression was employed to conduct statistical data analysis using SPSS software. RESULTS: The results indicated the most common recurrent copy neutral LOH (cnLOH) observed at 1p33-1p32.3, 1q32.2-1q42.13 and 6p12.1-6p11.1 loci in 8 (13%), 4 (7%), and 3 (5%) of the NSCL/P subjects, respectively. The cnLOHs at 1p33-1p32.3 (D1S197), 1q32.2-1q42.13 (D1S160), and 6p12.1-6p11.1 (D1S1661) were identified observed in NSCL/P and noncleft children using microsatellite analysis markers as a validation analysis. The regions affected by the cnLOHs at 1p33-1p32.3, 1q32.2-1q42.13, and 6p12.1-6p11.1 loci contained selected genes, namely FAF1, WNT3A and BMP5, respectively. There was a significant association between the D1S197 (1p33-32.3) markers containing the FAF1 gene among NSCL/P subjects with or without hypodontia compared with the noncleft subjects (p-value = 0.023). CONCLUSION: The results supported the finding that the genetic aberration on 1p33-32.3 significantly contributed to the development of NSCL/P with or without hypodontia. These results have an exciting prospect in the promising field of individualized preventive oral health care.

Novel truncating mutations in CTNND1 cause a dominant craniofacial and cardiac syndrome.

CTNND1 encodes the p120-catenin (p120) protein, which has a wide range of functions, including the maintenance of cell-cell junctions, regulation of the epithelial-mesenchymal transition and transcriptional signalling. Due to advances in next-generation sequencing, CTNND1 has been implicated in human diseases including cleft palate and blepharocheilodontic (BCD) syndrome albeit only recently. In this study, we identify eight novel protein-truncating variants, six de novo, in 13 participants from nine families presenting with craniofacial dysmorphisms including cleft palate and hypodontia, as well as congenital cardiac anomalies, limb dysmorphologies and neurodevelopmental disorders. Using conditional deletions in mice as well as CRISPR/Cas9 approaches to target CTNND1 in Xenopus, we identified a subset of phenotypes that can be linked to p120-catenin in epithelial integrity and turnover, and additional phenotypes that suggest mesenchymal roles of CTNND1. We propose that CTNND1 variants have a wider developmental role than previously described and that variations in this gene underlie not only cleft palate and BCD but may be expanded to a broader velocardiofacial-like syndrome.