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Background Successful embryogenesis relies on the coordinated interaction between genes and tissues. The transcription factors Pax9 and Msx1 genetically interact during mouse craniofacial morphogenesis, and mice deficient for either gene display abnormal tooth and palate development. Pax9 is expressed specifically in the pharyngeal endoderm at mid-embryogenesis, and mice deficient for Pax9 on a C57Bl/6 genetic background also have cardiovascular defects affecting the outflow tract and aortic arch arteries giving double-outlet right ventricle, absent common carotid arteries and interruption of the aortic arch. Results In this study we have investigated both the effect of a different genetic background and Msx1 haploinsufficiency on the presentation of the Pax9-deficient cardiovascular phenotype. Compared to mice on a C57Bl/6 background, congenic CD1-Pax9–/– mice displayed a significantly reduced incidence of outflow tract defects but aortic arch defects were unchanged. Pax9–/– mice with Msx1 haploinsufficiency, however, have a reduced incidence of interrupted aortic arch, but more cases with cervical origins of the right subclavian artery and aortic arch, than seen in Pax9–/– mice. This alteration in arch artery defects was accompanied by a rescue in third pharyngeal arch neural crest cell migration and smooth muscle cell coverage of the third pharyngeal arch arteries. Although this change in phenotype could theoretically be compatible with post-natal survival, using tissue-specific inactivation of Pax9 to maintain correct palate development whilst inducing the cardiovascular defects was unable to prevent postnatal death in the mutant mice. Hyoid bone and thyroid cartilage formation were abnormal in Pax9–/– mice. Conclusions Msx1 haploinsufficiency mitigates the arch artery defects in Pax9–/– mice, potentially by maintaining the survival of the 3rd arch artery through unimpaired migration of neural crest cells to the third pharyngeal arches. With the neural crest cell derived hyoid bone and thyroid cartilage also being defective in Pax9–/– mice, we speculate that the pharyngeal endoderm is a key signalling centre that impacts on neural crest cell behaviour highlighting the ability of cells in different tissues to act synergistically or antagonistically during embryo development.

The purpose of this research was to investigate and identify

Paired Box (Pax) gene family, a group of transcription regulators have been implicated in diverse physiological processes. However, their role during hematopoiesis which generate a plethora of blood cells remains largely unknown. Using a previously reported single cell transcriptomics data, we analyzed the expression of individual Pax family members in hematopoietic cells in zebrafish. We have identified that Pax9, which is an essential regulator for odontogenesis and palatogenesis, is selectively localized within a single cluster of the hematopoietic lineage. To further analyze the function of Pax9 in hematopoiesis, we generated two independent pax9 knock-out mutants using the CRISPR-Cas9 technique. We found that Pax9 appears to be an essential regulator for granulopoiesis but dispensable for erythropoiesis during development, as lack of pax9 selectively decreased the number of neutrophils with a concomitant decrease in the expression level of neutrophil markers. In addition, embryos, where pax9 was functionally disrupted by injecting morpholinos, failed to increase the number of neutrophils in response to pathogenic bacteria, suggesting that Pax9 is not only essential for developmental granulopoiesis but also emergency granulopoiesis. Due to the inability to initiate emergency granulopoiesis, innate immune responses were severely compromised in pax9 morpholino-mediated embryos, increasing their susceptibility and mortality. Taken together, our data indicate that Pax9 is essential for granulopoiesis and promotes innate immunity in zebrafish larvae.

Eutherian dentition has been the focus of a great deal of studies in the areas of evolution, development, and genomics. The development of molar teeth is regulated by an antero-to-posterior cascade mechanism of activators and inhibitors molecules, where the relative sizes of the second (M2) and third (M3) molars are dependent of the inhibitory influence of the first molar (M1). Higher activator/inhibitor ratios will result in higher M2/M1 or M3/M1. Pax9 has been shown to play a key role in tooth development. We have previously shown that a G-quadruplex in the first intron of Pax9 can modulate the splicing efficiency. Using a sliding window approach with we analyzed the association of the folding energy (Mfe) of the Pax9 first intron with the relative molar sizes in 42 mammalian species, representing 9 orders. The Mfe of two regions located in the first intron of Pax9 were shown to be significantly associated with the M2/M1 and M3/M1 areas and mesiodistal lengths. The first region is located at the intron beginning and can fold into a stable G4 structure, whereas the second is downstream the G4 and 265 bp from intron start. Across species, the first intron of Pax9 varied in G-quadruplex structural stability. The correlations were further increased when the Mfe of the two sequences were added. Our results indicate that this region has a role in the evolution of the mammalian dental pattern by influencing the relative size of the molars.

Nonsyndromic tooth agenesis is associated with variants in several genes. There are numerous genotype-phenotype publications involving many patients and kindreds. Here, we identified six Thai individuals in two families with nonsyndromic tooth agenesis, performed exome sequencing, and conducted functional experiments. Family 1 had four affected members carrying the heterozygous PAX9 variant, c.59CT (p.Pro20Leu). The p.Pro20Leu was previously reported in two families having four and three affected members. These seven cases and Proband-1 had agenesis of at least three third molars. Family 2 comprised two affected members with agenesis of all 12 molars. Both individuals were heterozygous for c.230GA (p.Arg77Gln) in PAX9, which has not been reported previously. This variant is predicted to be damaging, evolutionarily conserved, and resides in the PAX9 linking peptide. The BMP4 RNA levels in Proband-1's leukocytes were not significantly different from those in the controls, whereas BMP4 levels observed in Proband-2 were significantly increased. Moreover, the p.Arg77Gln variant demonstrated nuclear localization similar to the wild-type but resulted in significantly impaired transactivation of BMP4, a PAX9 downstream gene. In conclusion, we demonstrate that the PAX9 p.Pro20Leu is highly associated with absent third molars, while the novel PAX9 p.Arg77Gln impairs BMP4 transactivation and is associated with total molar agenesis.

Due to the complexity of clinical manifestations and the lack of standardized diagnostic criteria, it is still difficult to distinguish the etiological types of congenital edentulousness corresponding to genetic defects. This paper studies the application of deep learning image processing and digital image processing in medical images in detail and analyzes the functions of congenital edentulous hotspot genes. The cases in the control group and the study group were collected, and the gene mutations of direct sequence MSX1, PAX9, AXIN2, and BMP were analyzed, and new pathogens were found. The experimental results suggest that PAX9 and MSX1 genes may have a synergistic effect in nonsyndromic congenital edentulous patients. In severely missing teeth, the role of PAX9 may be greater than that of MSX1. The experimental results will help us lay the foundation for further understanding of the disease in the future.

Sonic Hedgehog/GLI3 signaling is critical in regulating digit number, such that Gli3-deficiency results in polydactyly and Shh-deficiency leads to digit number reductions. SHH/GLI3 signaling regulates cell cycle factors controlling mesenchymal cell proliferation, while simultaneously regulating Grem1 to coordinate BMP-induced chondrogenesis. SHH/GLI3 signaling also coordinates the expression of additional genes, however their importance in digit formation remain unknown. Utilizing genetic and molecular approaches, we identified HES1 as a downstream modifier of the SHH/GLI signaling axis capable of inducing preaxial polydactyly (PPD), required for Gli3-deficient PPD, and capable of overcoming digit number constraints of Shh-deficiency. Our data indicate that HES1, a direct SHH/GLI signaling target, induces mesenchymal cell proliferation via suppression of Cdkn1b, while inhibiting chondrogenic genes and the anterior autopod boundary regulator, Pax9. These findings establish HES1 as a critical downstream effector of SHH/GLI3 signaling in the development of PPD., Author summary Sonic Hedgehog/GLI3 signaling is critical in regulating digit number, such that Gli3-deficiency results in additional digits and Shh-deficiency leads to digit number reductions. SHH/GLI3 signaling within the developing limb regulates numerous genes critical for proper autopod (hand/foot) development, however not all target genes are known to be truly important for digit formation. Utilizing genetic and molecular approaches, we identified HES1 as a downstream modifier of the SHH/GLI signaling axis capable of inducing preaxial polydactyly (PPD), required for Gli3-deficient PPD, and capable of overcoming digit number constraints of Shh-deficiency. We further propose a mechanistic model by which HES1 coordinates the expression of genes important for proper digit development. These findings establish HES1 as a critical downstream effector of SHH/GLI3 signaling in the development of PPD.

The histone methyltransferase SET domain bifurcated 1 (SETDB1) catalyzes the trimethylation of lysine 9 of histone H3, thereby regulating gene expression. In this study, we used conditional knockout mice, where Setdb1 was deleted only in neural crest cells (Setdb1

To investigate the effect of PAX9 on the progression of cervical cancer (CC). PAX9 expression was quantified in CC tissues and adjacent normal tissues, as well as human CC cell lines and human cervical epithelial cells (HCerEpiC). PAX9-overexpression lentiviral vectors were transfected into CC cell lines, followed by the measurement of proliferation and apoptosis and the quantification of apoptosis-related proteins. In vivo, mice were subcutaneously injected with CaSki cells transfected with PAX9-overexpression lentiviral vectors and control vectors. Then, the volume and weight of tumors were measured followed by hematoxylin and eosin (HE) staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, and immunohistochemistry. PAX9 expression in the CC tissues was lower than that in the adjacent normal tissues, which was correlated with the FIGO stage, tumor size, infiltration depth, parametrium invasion, lympho-vascular space invasion tumor-positive lymph nodes, and prognosis. Furthermore, PAX9 in CC cell lines was also lower than in HCerEpiC. PAX9 inhibits the CC cell proliferation and promotes the apoptosis, with the up-regulations of caspase-3, poly(ADP-ribose) polymerase (PARP), and Bax and the down-regulation of Bcl-2. In vivo experiments demonstrated that in the PAX9 group, the tumor weight and volume were lower than those in the vector group accompanying the decreased Ki-67, cleaved-caspase-3, and Bax expressions and the increased TUNEL and Bcl-2 expression. PAX9 was lowly expressed in the CC tissues and associated with the clinicopathological characteristics and prognosis. PAX9 could inhibit proliferation of CC cell lines and promote the apoptosis, thus suppressing the tumor growth in vivo, indicating its potential therapeutic role for CC treatment.

Aberrant DNA hypermethylation is associated with oral carcinogenesis. Procaine, a local anesthetic, is a DNA methyltransferase (DNMT) inhibitor that activates anticancer mechanisms. However, its effect on silenced tumor suppressor gene (TSG) activation and its biological role in oral squamous cell carcinoma (OSCC) remain unknown. Here, we report procaine inhibited DNA methylation by suppressing DNMT activity and increased the expression of PAX9, a differentiation gene in OSCC cells. Interestingly, the reactivation of PAX9 by procaine found to inhibit cell growth and trigger apoptosis in OSCC in vitro and in vivo. Likely, the enhanced PAX9 expression after exposure to procaine controls stemness and differentiation through the autophagy-dependent pathway in OSCC cells. PAX9 inhibition abrogated procaine-induced apoptosis, autophagy, and inhibition of stemness. In OSCC cells, procaine improved anticancer drug sensitivity through PAX9, and its deficiency significantly blunted the anticancer drug sensitivity mediated by procaine. Additionally, NRF2 activation by procaine facilitated the antitumor response of PAX9, and pharmacological inhibition of NRF2 by ML385 reduced death and prevented the decrease in the orosphere-forming potential of OSCC cells. Furthermore, procaine promoted antitumor activity in FaDu xenografts in athymic nude mice, and immunohistochemistry data showed that PAX9 expression was significantly enhanced in the procaine group compared to the vehicle control. In conclusion, PAX9 reactivation in response to DNMT inhibition could trigger a potent antitumor mechanism to provide a new therapeutic strategy for OSCC.

Digital, Background: In an effort to contribute to overcoming the platinum resistance exhibited by most solid tumors, we performed an array of epigenetic approaches, integrating next-generation methodologies and public clinical data to identify new potential epi-biomarkers in ovarian cancer, which is considered the most devastating of gynecological malignancies. Methods: We cross-analyzed data from methylome assessments and restoration of gene expression through microarray expression in a panel of four paired cisplatin-sensitive/cisplatin-resistant ovarian cancer cell lines, along with publicly available clinical data from selected individuals representing the state of chemoresistance. We validated the methylation state and expression levels of candidate genes in each cellular phenotype through Sanger sequencing and reverse transcription polymerase chain reaction, respectively. We tested the biological role of selected targets using an ectopic expression plasmid assay in the sensitive/resistant tumor cell lines, assessing the cell viability in the transfected groups. Epigenetic features were also assessed in 189 primary samples obtained from ovarian tumors and controls. Results: We identified PAX9 and FKBP1B as potential candidate genes, which exhibited epigenetic patterns of expression regulation in the experimental approach. Re-establishment of FKBP1B expression in the resistant OVCAR3 phenotype in which this gene is hypermethylated and inhibited allowed it to achieve a degree of platinum sensitivity similar to the sensitive phenotype. The evaluation of these genes at a translational level revealed that PAX9 hypermethylation leads to a poorer prognosis in terms of overall survival. We also set a precedent for establishing a common epigenetic signature in which the validation of a single candidate, MEST, proved the accuracy of our computational pipelines. Conclusions: Epigenetic regulation of PAX9 and FKBP1B genes shows that methylation in non-promoter areas has the potential to control gene expression and thus biological consequences, such as the loss of platinum sensitivity. At the translational level, PAX9 behaves as a predictor of chemotherapy response to platinum in patients with ovarian cancer. This study revealed the importance of the transcript-specific study of each gene under potential epigenetic regulation, which would favor the identification of new markers capable of predicting each patient's progression and therapeutic response., Ciencias Médicas y de la Salud

Abnormalities in genetic and epigenetic modifications can lead to drastic changes in gene expression profiles that are associated with various cancer types. Small cell lung cancer (SCLC) is an aggressive and deadly form of lung cancer with limited effective therapies currently available. By utilizing a genome-wide CRISPR-Cas9 dropout screen in SCLC cells, we identified paired box protein 9 (PAX9) as an essential factor that is overexpressed in human malignant SCLC tumor samples and is transcriptionally driven by the BAP1/ASXL3/BRD4 epigenetic axis. Genome-wide studies revealed that PAX9 occupies distal enhancer elements and represses gene expression by restricting enhancer activity. In multiple SCLC cell lines, genetic depletion of PAX9 led to significant induction of a primed-active enhancer transition, resulting in increased expression of a large number of neural differentiation and tumor-suppressive genes. Mechanistically, PAX9 interacted and cofunctioned with the nucleosome remodeling and deacetylase (NuRD) complex at enhancers to repress nearby gene expression, which was reversed by pharmacologic HDAC inhibition. Overall, this study provides mechanistic insight into the oncogenic function of the PAX9/NuRD complex epigenetic axis in human SCLC and suggests that reactivation of primed enhancers may have potential therapeutic efficacy in treating SCLC expressing high levels of PAX9. Significance: A genome-wide screen in small cell lung cancer reveals PAX9/NuRD-mediated epigenetic enhancer silencing and tumor progression, supporting the development of novel personalized therapeutic approaches targeting the PAX9-regulated network.

Orientadores: Sérgio Roberto Peres Line, Marcelo Rocha Marques Texto em português e inglês Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba Resumo: G-Quadruplexes são estruturas secundárias presentes nas moléculas de DNA e RNA, os quais são formados pelo empilhamento de G-quartetos (interação de quatro guaninas (G-tratos) delimitadas por ligações de hidrogênio do tipo Hoogsteen. O intron 1 do gene PAX9 humano tem um G-quadruplex formado na região localizada perto do exon 1, que é conservada entre os mamíferos placentários. Análises de Dicroísmo Circular (CD), e CD melting mostraram que estas sequências são capazes de formar estruturas quadruplex altamente estáveis. Devido à proximidade da estrutura quadruplex ao limite éxon-íntron foi utilizado um ensaio validado de splicing duplo repórter e PCR em tempo real para analisar o seu papel na eficiência de splicing. O quadruplex humano mostrou ter um papel chave na eficiência de splicing do íntron 1 do gene PAX9, já que uma mutação que aboliu a formação do quadruplex diminuiu drasticamente a eficiência de splicing. O quadruplex de rato, menos estável, mostrou menor eficiência quando comparado com sequências humanas. Além disso, o tratamento com 360A, um forte ligante que estabiliza estruturas quadruplex, aumentou ainda mais a eficiência de splicing do íntron 1 do PAX9 humano. Em conjunto estes resultados fornecem evidências de que as estruturas de G-quadruplex estão envolvidas na eficiência de splicing do intron 1 do gene PAX9 Abstract: G-Quadruplex are secondary structures present in DNA and RNA molecules, which are formed by stacking of G-quartets (i.e. interaction of four guanines (G-tracts) bounded by Hoogsteen hydrogen bonding). Human PAX9 intron 1 has a putative G-quadruplex- forming region located near exon 1, which is conserved among placental mammals. Using Circular Dichroism (CD) analysis, and CD melting we showed that this region is able to form highly stable quadruplex structures. Due to the proximity of the quadruplex structure to exon-intron boundary we used a validated double reporter splicing assay and real time PCR to analyze its role on splicing efficiency. The human quadruplex was shown to have a key role on splicing efficiency of PAX9 intron 1, as a mutation that abolished quadruplex formation decreased dramatically splicing efficiency. The less stable, rat quadruplex had a less efficient splicing when comparing to human sequences. Additionally, the treatment with 360A, a strong ligand that stabilizes quadruplex structures, further increased splicing efficiency of human PAX9 intron 1. Altogether these results provide evidences that G-quadruplex structures are involved in splicing efficiency of PAX9 intron 1 Doutorado Histologia e Embriologia Doutora em Biologia Buco-Dental

The etiology of hypodontia is complex, in which both genetic and environmental factors can be related. The main objective of our study was to contribute to elucidating the genetic background of nonsyndromic hypodontia (NSH). In this order, we selected 97 NSH subjects (70 females and 27 males) from patients referred to orthodontic treatment, and we matched to each NSH subject a control by age and sex. DNA was obtained from epithelial cells from the oral mucosa. Genotyping of the PAX9 (rs4904155 and rs61754301), MSX1 (rs8670 and rs12532), and AXIN2 (rs2240308) SNPs was performed by using TaqMan SNP Genotyping Assays on a real-time PCR system. Single-nucleotide polymorphisms (SNPs) were studied for the whole NSH group and for frontal and lateral agenesis NSH subjects separately. Our results showed that the variant genotype (p=0.0008, OR = 2.9, 95% CI = 1.58–5.3) and variant T allele (p=0.0002, OR = 2.65, 95% CI = 1.6–4.39) of the MSX1 rs8670 SNP increased the risk of hypodontia in the studied population when the whole NSH group was compared with controls. The variant genotype of the MSX1 rs8670 SNP was the most frequent in frontal agenesis; meanwhile in the lateral agenesis NSH group, the AXIN2 rs2240308 SNP showed a higher frequency of the variant genotype, with a trend towards statistical significance. In conclusion, the results of the present study showed that the variant genotype and variant T allele of the MSX1 rs8670 SNP increased the risk of hypodontia in the studied population. The presence of the variant A allele of AXIN2 rs2240308 is associated with frontal agenesis but not with lateral agenesis.

Head and neck cancer (HNC) remains one of the most malignant tumors with a significantly high mortality. DNA methylation exerts a vital role in the prognosis of HNC. In this study, we try to screen abnormal differential methylation genes (DMGs) and pathways in Head–Neck Squamous Cell Carcinoma via integral bioinformatics analysis. Data of gene expression microarrays and gene methylation microarrays were obtained from the Cancer Genome Atlas database. Aberrant DMGs were identified by the R Limma package. We conducted the Cox regression analysis to select the prognostic aberrant DMGs and site‐specific methylation. Five aberrant DMGs were recognized that significantly correlated with overall survival. The prognostic model was constructed based on five DMGs (PAX9, STK33, GPR150, INSM1, and EPHX3). The five DMG models acted as prognostic biomarkers for HNC. The area under the curve based on the five DMGs predicting 5‐year survival is 0.665. Moreover, the correlation between the DMGs/site‐specific methylation and gene expression was also explored. The findings demonstrated that the five DMGs can be used as independent prognostic biomarkers for predicting the prognosis of patients with HNC. Our study might lay the groundwork for further mechanism exploration in HNC and may help identify diagnostic biomarkers for early stage HNC.

Objective: Maxillary canines are the second-most commonly impacted teeth. About two-thirds of the impacted maxillary canines are palatally impacted. Studies in the past have shown that 40% of cases with palatal impaction of maxillary canines presented with agenesis of third molars. Sporadic agenesis of third molars have been associated with polymorphisms in the MSX1 and PAX9 genes. The present study aims at evaluating the association between polymorphisms of PAX9, MSX1 and palatally impacted canines in a random population sample. Design and setting: Fifty individuals with palatally impacted maxillary canines and 50 gender and age-matched controls were included in this study. Methods: Single nucleotide polymorphisms (SNPs), rs12532 of MSX1 and rs2073247 of PAX9, were genotyped using polymerase chain reaction and restriction fragment length polymorphism. The significance of the differences among the groups was assessed by odds ratio and Chi-squared test with a 95% confidence interval Results: Single nucleotide polymorphisms rs12532 [MSX1] and rs 2073247 [PAX9] showed a statistically significant association with palatal impaction of maxillary canines. In addition, the combined presence of the AG/CT genotypes of these genes in an individual caused a significant increase in the risk for palatal impaction. Conclusion: These results suggest that the rs12532 and rs2073247 polymorphisms of genes MSX1 and PAX9 are positively associated with palatal impaction of maxillary canines. Future studies investigating various other SNPs of these genes in a larger sample of different populations could provide clinching details.

Objectives To identify potentially pathogenic mutations for tooth agenesis by whole-exome sequencing. Subjects and methods Ten Chinese families including five families with ectodermal dysplasia (syndromic tooth agenesis) and five families with selective tooth agenesis were included. Whole-exome sequencing was performed using genomic DNA. Potentially pathogenic mutations were identified after data filtering and screening. The pathogenicity of novel variants was investigated by segregation analysis, in silico analysis, and functional studies. Results One novel mutation (c.441_442insACTCT) and three reported mutations (c.252delT, c.463C>T, and c.1013C>T) in EDA were identified in families with ectodermal dysplasia. The novel EDA mutation was co-segregated with phenotype. A functional study revealed that NF-κB activation was compromised by the identified mutations. The secretion of active EDA was also compromised detection by western blotting. Novel Wnt10A mutations (c.521T>C and c.653T>G) and EVC2 mutation (c.1472C>T) were identified in families with selective tooth agenesis. The Wnt10A c.521T>C mutation and the EVC2 c.1472C>T mutation were considered as pathogenic for affecting highly conserved amino acids, co-segregated with phenotype and predicted to be disease-causing by SIFT and PolyPhen2. Moreover, several reported mutations in PAX9, Wnt10A, and FGFR3 were also detected. Conclusions Our study expanded our knowledge on tooth agenesis spectrum by identifying novel variants.

Proteins expressed by the paired box gene 9 (PAX9) and Msh Homeobox 1 (MSX1) are intimately involved in tooth development (odontogenesis). The regulation of PAX9 and MSX1 protein turnover by deubiquitinating enzymes (DUBs) plausibly maintain the required levels of PAX9 and MSX1 during odontogenesis. Herein, we used a loss-of-function CRISPR-Cas9-mediated DUB KO library kit to screen for DUBs that regulate PAX9 and MSX1 protein levels. We identify and demonstrate that USP49 interacts with and deubiquitinates PAX9 and MSX1, thereby extending their protein half-lives. On the other hand, the loss of USP49 reduces the levels of PAX9 and MSX1 proteins, which causes transient retardation of odontogenic differentiation in human dental pulp stem cells and delays the differentiation of human pluripotent stem cells into the neural crest cell lineage. USP49 depletion produced several morphological defects during tooth development, such as reduced dentin growth with shrunken enamel space, and abnormal enamel formation including irregular mineralization. In sum, our results suggest that deubiquitination of PAX9 and MSX1 by USP49 stabilizes their protein levels to facilitate successful odontogenesis.

苏州大学附属第二医院口腔中心收治单纯型多数牙缺失1例，患者先天缺失恒牙16颗，其他系统无异常，其母与患者有相似表型。收集患者、患者父母及外祖父母外周血，提取DNA，采用PCR结合直接测序进行PAX9、MSX1、WNT10A、WNT10B、AXIN2和EDA等候选基因突变检测，PCR-Sanger测序发现PAX9基因的起始密码子存在1个杂合突变，即NM006194.3（PAX9）：c.2TC（p.Met1Thr），使起始密码子突变为苏氨酸，患者母亲有相同突变，可能是该患者先天单纯型多数牙缺失的遗传致病原因。患者拔除口内滞留乳牙后进行正畸-修复序列治疗，疗效满意。.

Paired box 9 (PAX9) is a transcription factor of the PAX family functioning as both a transcriptional activator and repressor. Its functional roles in the embryonic development of various tissues and organs have been well studied. However, its roles and molecular mechanisms in cancer development are largely unknown. Here, we review the current understanding of PAX9 expression, upstream regulation of PAX9, and PAX9 downstream events in cancer development. Promoter hypermethylation, promoter SNP, microRNA, and inhibition of upstream pathways (e.g., NOTCH) result in PAX9 silencing or downregulation, whereas gene amplification and an epigenetic axis upregulate PAX9 expression. PAX9 may contribute to carcinogenesis through dysregulation of its transcriptional targets and related molecular pathways. In summary, extensive studies on PAX9 in its cellular and tissue contexts are warranted in various cancers, in particular, HNSCC, ESCC, lung cancer, and cervical SCC.

Like all developmental processes, odontogenesis is highly complex and dynamically regulated, with hundreds of genes co-expressed in reciprocal networks. Tooth agenesis (missing one or more/all teeth) is a common human craniofacial anomaly and may be caused by genetic variations and/or environmental factors. Variants in PAX9, MSX1, AXIN2, EDA, EDAR, and WNT10A genes are associated with tooth agenesis. Currently, variants in ATF1, DUSP10, CASC8, IRF6, KDF1, GREM2, LTBP3, and components and regulators of WNT signaling WNT10B, LRP6, DKK, and KREMEN1 are at the forefront of interest. Due to the interconnectedness of the signaling pathways of carcinogenesis and odontogenesis, tooth agenesis could be a suitable marker for early detection of cancer predisposition. Variants in genes associated with tooth agenesis could serve as prognostic or therapeutic targets in cancer. This review aims to summarize existing knowledge of development and clinical genetics of teeth. Concurrently, the review proposes possible approaches for future research in this area, with particular attention to roles in monitoring, early diagnosis and therapy of tumors associated with defective tooth development.

Alcohol drinking has been established as a major risk factor for esophageal diseases. Our previous study showed that ethanol exposure inhibited PAX9 expression in human esophageal squamous epithelial cells in vitro and in vivo. In this study, we aimed to investigate the molecular pathways through which alcohol drinking suppresses PAX9 in esophageal squamous epithelial cells. We first demonstrated the inhibition of NOTCH by ethanol exposure in vitro. NOTCH regulated PAX9 expression in KYSE510 and KYSE410 cells in vitro and in vivo. RBPJ and NOTCH intracellular domain (NIC) D1 ChIP-PCR confirmed Pax9 as a direct downstream target of NOTCH signaling in mouse esophagus. NOTCH inhibition by alcohol drinking was further validated in mouse esophagus and human tissue samples. In conclusion, ethanol exposure inhibited NOTCH signaling and thus suppressed PAX9 expression in esophageal squamous epithelial cells in vitro and in vivo. Our data support a novel mechanism of alcohol-induced esophageal injury through the inhibition of NOTCH-PAX9 signaling. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Objectives To investigate pathogenic variants of the paired box 9 (PAX9) gene in patients with non-syndromic oligodontia, and the functional impact of these variants. Subjects and methods Whole exome sequencing and Sanger sequencing were utilized to detect gene variants in a cohort of 80 patients diagnosed with non-syndromic oligodontia. Bioinformatic and conformational analyses, fluorescence microscopy and luciferase reporter assay were employed to explore the functional impact. Results We identified three novel variants in the PAX9, including two frameshift variants (c.211_212insA; p.I71Nfs*246 and c.236_237insAC; p.T80Lfs*6), and one missense variant (c.229C > G; p.R77G). Familial co-segregation verified an autosomal-dominant inheritance pattern. Conformational analyses revealed that the variants resided in the paired domain, and could cause corresponding structural impairment of the PAX9 protein. Fluorescence microscopy showed abnormal subcellular localizations of frameshift variants, and luciferase assay showed impaired downstream transactivation activities of the bone morphogenetic protein 4 (BMP4) gene in all variants. Conclusions Our findings broaden the spectrum of PAX9 variants in patients with non-syndromic oligodontia and support that paired domain structural impairment and the dominant-negative effect are likely the underlying mechanisms of PAX9-related non-syndromic oligodontia. Our findings will facilitate genetic diagnosis and counselling, and help lay the foundation for precise oral health therapies.

The aim of this study is to genotype thirteen Single Nucleotide Polymorphisms (SNPs) within the paired box gene 9 (PAX9) in 36 Jordanian Arab families with peg-shaped teeth, and also to investigate the association between the PAX9 gene and peg-shaped teeth disorder.Genomic DNA samples were extracted from families according to distinguished processes. Then, DNA was amplified by polymerase chain reaction technique (PCR) using specified primers for the exons of the PAX9 gene. In addition, single nucleotide polymorphisms analysis was conducted using the DNA sequencing genotyping method to identify specific single nucleotide polymorphisms in the PAX9 gene associated with peg-shaped teeth.Thirteen single nucleotide polymorphisms in the PAX9 gene (Chromosome 14q13.3) were used; seven of them (rs104894467, rs104894469, rs28933373, rs28933970, rs28933971, rs28933972, and rs7143727) were non-polymorphic, and the other six were polymorphic (rs2073244, rs2073246, rs2295222, rs4904155, rs4904210, and rs12881240). Both rs12881240 and rs2295222 SNPs showed significant association with peg-shaped teeth disorder (P0.05). Moreover, the haplotype genetic analysis revealed that there is a genetic association with peg-shaped teeth disorder susceptibility (P0.05) in the Jordanian families of Arab descent.Our findings exhibited significant variations compared to the data recorded from other countries.

Objectives This study aimed to initially screen more susceptible variations at PAX9 gene in non-syndromic cleft palate only cases and then test their associations in independent non-syndromic orofacial cleft subtypes from Western Han Chinese population. Design Initially exons at PAX9 gene were screened for variations among 180 non-syndromic cleft palate only patients by the Sanger sequencing method, and the genotype data from 1000 Genomes Project Database was taken as control to perform Chi-square test. Subsequently, we performed association analysis among 2202 non-syndromic orofacial cleft patients (938 non-syndromic cleft palate only cases, 456 non-syndromic cleft lip only cases and 808 non-syndromic cleft lip and palate cases) and 1823 normal controls to replicate the role of two significant single nucleotide polymorphisms. Results Two intronic single nucleotide polymorphism rs12885612 (P = 0.047, OR = 0.671 and 95−0.996) and rs12881248 (P = 0.047, OR = 1.006 and 95 %CI: 0.443−0.995) were associated non-syndromic cleft palate only in the initial screen phase. Surprisingly, in replication analysis rs12885612 (P = 0.048, OR = 1.25, 95 %CI: 1.0–1.56) and rs12881248 (P = 0.037, OR = 1.26, 95 %CI: 1.01−1.57) exhibited significant association signal in non-syndromic cleft lip only group, but not in non-syndromic cleft palate only group. Conclusion In summary, this study firstly revealed that rs12885612 and rs12881248 at PAX9 gene associated with non-syndromic cleft lip only from Western Han Chinese population, which indicated that PAX9 is a promising susceptible gene for non-syndromic cleft lip only in Western Han Chinese population.

Dysregulation of ribosome production can lead to a number of developmental disorders called ribosomopathies. Despite the ubiquitous requirement for these cellular machines used in protein synthesis, ribosomopathies manifest in a tissue-specific manner, with many affecting the development of the face. Here we reveal yet another connection between craniofacial development and making ribosomes through the protein Paired Box 9 (PAX9). PAX9 functions as an RNA Polymerase II transcription factor to regulate the expression of proteins required for craniofacial and tooth development in humans. We now expand this function of PAX9 by demonstrating that PAX9 acts outside of the cell nucleolus to regulate the levels of proteins critical for building the small subunit of the ribosome. This function of PAX9 is conserved to the organism Xenopus tropicalis, an established model for human ribosomopathies. Depletion of pax9 leads to craniofacial defects due to abnormalities in neural crest development, a result consistent with that found for depletion of other ribosome biogenesis factors. This work highlights an unexpected layer of how the making of ribosomes is regulated in human cells and during embryonic development., Author summary We are only beginning to understand the complex process of making human ribosomes, the cellular machines critical for all protein synthesis. In humans, making a ribosome requires hundreds of regulatory factors to ensure proper cellular growth and development. Dysregulation of this process can lead to a number of tissue specific disorders, termed ribosomopathies. Here, we have discovered a new role for the protein Paired Box 9 (PAX9) in making human ribosomes. While PAX9 has traditionally been known to play a role in regulating the levels of proteins required for craniofacial and tooth development in humans, we expand this function of PAX9 by showing that PAX9 acts outside of the cell nucleolus to regulate the levels of proteins critical for building the small subunit of the ribosome. In addition, we show that this function is conserved to the model organism, Xenopus tropicalis. This link between PAX9’s role in craniofacial development and in ribosome biogenesis may lead to new insights into the pathogenesis of these PAX9 mutations in humans.

Aims Vascular smooth muscle cells (VSMCs) play a crucial role in the progression of atherosclerosis. Paired box 9 (Pax9) is a member of the Pax gene family which participates in the development of various tissues and organs. However, the effect of Pax9 on atherosclerosis and VSMCs and the underlying mechanisms remain unclear. Main methods Western blotting was performed to assess Pax9 expression in atherosclerosis and VSMCs. Pax9 siRNA and overexpression plasmid were constructed to explore the biological function. Cell proliferation assay, phalloidin staining, and Transwell assay, accompanied by the sonic hedgehog (Shh) signaling pathway antagonist, cyclopamine (5 μM) and agonist, SAG (100 nM), were used to evaluate the VSMC phenotype, proliferation, and migration, as well as explore the associated mechanisms. Key findings We first discovered Pax9 to be significantly increased in atherosclerotic mice and platelet-derived growth factor-BB (PDGF-BB)-induced VSMCs. Pax9 knockdown inhibited the phenotypic transformation, proliferation, and migration of VSMCs, whereas the opposite effect was observed when Pax9 was overexpressed. Next, we established that Shh was activated in PDGF-BB-induced VSMCs. Moreover, Pax9 overexpression further activated Shh and exacerbated the phenotypic transformation, proliferation, and migration of PDGF-BB-induced VSMCs. These changes were effectively inhibited by treatment with the Shh signaling pathway antagonist. Consistently, Pax9 knockdown down-regulated Shh expression and inhibited the phenotypic transformation, proliferation, and migration of PDGF-BB-induced VSMCs. Treatment with the Shh signaling pathway agonist prevented these changes. Significance Pax9 regulated VSMC phenotypic transformation, proliferation, and migration via Shh, which may represent a novel target for the treatment of atherosclerosis.

Tooth agenesis (TA) is one of the most common developmental anomalies that affects the number of teeth. An extensive analysis of publicly accessible databases revealed 15 causative genes responsible for nonsyndromic TA, along with their signaling pathways in Wnt/β-catenin, TGF-β/BMP, and Eda/Edar/NF-κB. However, genotype-phenotype correlation analysis showed that most of the causal genes are also responsible for syndromic TA or other conditions. In a total of 198 different mutations of the 15 genes responsible for nonsyndromic TA, 182 mutations (91.9%) are derived from seven genes (AXIN2, EDA, LRP6, MSX1, PAX9, WNT10A, and WNT10B) compared with the remaining 16 mutations (8.1%) identified in the remaining eight genes (BMP4, DKK1, EDAR, EDARADD, GREM2, KREMEN1, LTBP3, and SMOC2). Furthermore, specificity analysis in terms of the ratio of nonsyndromic TA mutations versus syndromic mutations in each of the aforementioned seven genes showed a 98.2% specificity rate in PAX9, 58.9% in WNT10A, 56.6% in MSX1, 41.2% in WNT10B, 31.4% in LRP6, 23.8% in AXIN2%, and 8.4% in EDA. These findings underscore an important role of the Wnt and Wnt-associated pathways in the genetic etiology of this heterozygous disease and shed new lights on the discovery of novel molecular mechanisms associated with tooth agenesis.

Introduction An extended family presenting with several members affected by developmentally missing teeth was investigated by analysis of the MSX1 and PAX9 genes. Materials and methods Saliva samples were collected and DNA extracted. Primers were designed to span the exons and intron-exon junctions of the MSX1 and PAX9 genes. These primers were optimised using gradient Polymerase Chain Reaction. The amplified fragments were sent for Sanger sequencing Results a novel heterozygote missense mutation in exon 3 of PAX9 (c.296G > C, p.A99P), was found in two severely affected members of the family as well as a potentially pathogenic heterozygote variant (c.119C > G, p.A40G) in exon 1 of the MSX1 gene. Conclusion The PAX9 A99P mutation is in the DNA binding domain and is predicted to be pathogenic.

Paired box 9 (PAX9) gene belongs to the PAX family, which encodes a family of metazoan transcription factors documented by a conserved DNA binding paired domain 128-amino-acids, critically essential for physiology and development. It is primarily expressed in embryonic tissues, such as the pharyngeal pouch endoderm, somites, neural crest-derived mesenchyme, and distal limb buds. PAX9 plays a vital role in craniofacial development by maintaining the odontogenic potential, mutations, and polymorphisms associated with the risk of tooth agenesis, hypodontia, and crown size in dentition. The loss-of-function of PAX9 in the murine model resulted in a short life span due to the arrest of cleft palate formation and skeletal abnormalities. According to recent studies, the PAX9 gene has a significant role in maintaining squamous cell differentiation, odontoblast differentiation of pluripotent stem cells, deregulation of which is associated with tumor initiation, and malignant transformation. Moreover, PAX9 contributes to promoter hypermethylation and alcohol- induced oro-esophageal squamous cell carcinoma mediated by downregulation of differentiation and apoptosis. Likewise, PAX9 activation is also reported to be associated with drug sensitivity. In summary, this current review aims to understand PAX9 function in the regulation of development, differentiation, and carcinogenesis, along with the underlying signaling pathways for possible cancer therapeutics.

Tooth agenesis is one of the most common developmental anomalies affecting function and esthetics. The paired-domain transcription factor, Pax9, is critical for patterning and morphogenesis of tooth and taste buds. Mutations of PAX9 have been identified in patients with tooth agenesis. Despite significant progress in the genetics of tooth agenesis, many gaps in knowledge exist in refining the genotype-phenotype correlation between PAX9 and tooth agenesis. In the present study, we complete genetic and phenotypic characterization of multiplex Chinese families with nonsyndromic (NS) tooth agenesis. Direct sequencing of polymerase chain reaction products revealed 9 novel (c.140G>C, c.167T>A, c.332G>C, c.194C>A, c.271A>T, c.146delC, c.185_189dup, c.256_262dup, and c.592delG) and 2 known heterozygous mutations in the PAX9 gene among 120 probands. Subsequently, pedigrees were extended, and we confirmed that the mutations co-segregated with the tooth agenesis phenotype (with exception of families in which DNA analysis was not available). In 1 family ( n = 6), 2 individuals harbored both the PAX9 c.592delG mutation and a heterozygous missense mutation (c.739C>T) in the MSX1 gene. Clinical characterization of families segregating a PAX9 mutation reveal that all affected individuals were missing the mandibular second molar and their maxillary central incisors are most susceptible to microdontia. A significant reduction of bitter taste perception was documented in individuals harboring PAX9 mutations ( n = 3). Functional studies revealed that PAX9 haploinsufficiency or a loss of function of the PAX9 protein underlies tooth agenesis.

Background In chronic lymphocytic leukemia (CLL), epigenomic and genomic studies have expanded the existing knowledge about the disease biology and led to the identification of potential biomarkers relevant for implementation of personalized medicine. In this study, an attempt has been made to examine and integrate the global DNA methylation changes with gene expression profile and their impact on clinical outcome in early stage CLL patients. Results The integration of DNA methylation profile (n = 14) with the gene expression profile (n = 21) revealed 142 genes as hypermethylated-downregulated and; 62 genes as hypomethylated-upregulated in early stage CLL patients compared to CD19+ B-cells from healthy individuals. The mRNA expression levels of 17 genes identified to be differentially methylated and/or differentially expressed was further examined in early stage CLL patients (n = 93) by quantitative real time PCR (RQ-PCR). Significant differences were observed in the mRNA expression of MEIS1, PMEPA1, SOX7, SPRY1, CDK6, TBX2, and SPRY2 genes in CLL cells as compared to B-cells from healthy individuals. The analysis in the IGHV mutation based categories (Unmutated = 39, Mutated = 54) revealed significantly higher mRNA expression of CRY1 and PAX9 genes in the IGHV unmutated subgroup (p

Paired box 9 (PAX9) is one of the best-known transcription factors involved in the development of human dentition. Mutations in PAX9 gene could, therefore, seriously influence the number, position and morphology of the teeth in an affected individual. To date, over 50 mutations in the gene have been reported as associated with various types of dental agenesis (congenitally missing teeth) and other inherited dental defects or variations. The most common consequence of PAX9 gene mutation is the autosomal-dominant isolated (non-syndromic) oligodontia or hypodontia. In the present review, we are summarizing all known PAX9 mutations as well as their nature and precise loci in the DNA sequence of the gene. Where necessary, we have revised the loci of the mutations in line with the reference sequence of the PAX9 gene as it appears in the current DNA databases.

Abnormal paired box 9 (PAX9) expression is associated with tumorigenesis, cancer development, invasion and metastasis. The present study investigated the prognostic significance of PAX9 in esophageal squamous cell carcinoma (ESCC) and its role in predicting radiation sensitivity. A total of 52.8% (121/229) ESCC tissues were positive for PAX9. The 1-, 3- and 5-year disease-free survival (DFS) rates were 72.2, 35.2 and 5.6%, respectively, and the overall survival (OS) rates were and 86.1, 44.4, and 23.1%, respectively, in PAX9-positive tumors. In PAX9-negative tumors, the one-, three- and five-year DFS rates were 76.9, 47.9 and 24.0%, and the OS rates were 90.9, 57.9 and 38.8%, respectively. Univariate analysis revealed that PAX9, differentiation, T stage, lymph node metastasis, and tumor-node-metastasis stage were associated with OS. Multivariate analysis of DFS and OS revealed that the hazard ratios for PAX9 were 0.624 (95% CI: 0.472–0.869, P=0.004) and 0.673 (95% CI: 0.491–0.922, P=0.014), respectively. Patients that received adjuvant therapy exhibited significant differences in the 5-year DFS (P

PAX2, a member of paired box family, is an essential transcription factor for the organ development in vertebrates including teleosts, yet no evidence has been shown for its involvement in reproduction. To study this, partial- and/or full-length cDNA ofpax2was isolated from the ovary of catfish,Clarias batrachus, along with its other Pax family members,pax1andpax9. Tissue distribution and ontogeny expression analysis indicated the prevalence ofpax2but notpax1andpax9in ovary. Varied phase-wise expression during ovarian cycle and elevation ofpax2after human chorionic gonadotropin induction showed probable regulation by gonadotropins. Pax2 could be localized in various stages of oocytes and in follicular layer of vitellogenic and post-vitellogenic oocytes. To assess the functional significance ofpax2, transient RNA silencing was performed using primary catfish ovarian follicle culture,in vitro, and in catfish,in vivo, through ovary-targeted injection of PEI-esiRNA. Pax2 siRNA treatment reduced the expression of various transcripts related to ovarian development like signaling molecules such aswnt4andwnt5, estrogen receptors, several steroidogenic enzymes and transcription factors. These transitions in transcript levels might have been mediated by Pax2 acting upstream ofwnt4/5that may play a role in steroidogenesis and/or ovarian development along withad4bp/sf-1or by direct or indirect interaction with steroidogenic enzyme genes, which is evident from the change in the levels of serum estradiol-17β but not 17α,20β-dihydroxy-4-pregnen-3-one. Taken together, it seems thatpax2has a plausible role during ovarian development and/or recrudescence of catfish either directly or indirectly through Wnt signaling pathway.

In this study, we investigated the role of the transcription factor Six2 in palate development. Six2 was selected using the SysFACE tool to predict genes from the 2p21 locus, a region associated with clefting in humans by GWAS, that are likely to be involved in palatogenesis. We functionally validated the predicted role of Six2 in palatogenesis by showing that 22% of Six2 null embryos develop cleft palate. Six2 contributes to palatogenesis by promoting mesenchymal cell proliferation and regulating bone formation. The clefting phenotype in Six2(−/−) embryos is similar to Pax9 null embryos, so we examined the functional relationship of these two genes. Mechanistically, SIX2 binds to a PAX9 5’ upstream regulatory element and activates PAX9 expression. In addition, we identified a human SIX2 coding variant (p.Gly264Glu) in a proband with cleft palate. We show this missense mutation affects the stability of the SIX2 protein and leads to decreased PAX9 expression. The low penetrance of clefting in the Six2 null mouse combined with the mutation in one patient with cleft palate underscores the potential combinatorial interactions of other genes in clefting. Our study demonstrates that Six2 interacts with the developmental gene regulatory network in the developing palate.

Background Despite the strides made in understanding the complex network of key regulatory genes and cellular processes that drive palate morphogenesis, patients suffering from these conditions face treatment options that are limited to complex surgeries and multidisciplinary care throughout life. Hence, a better understanding of how molecular interactions drive palatal growth and fusion is critical for the development of treatment and preventive strategies for cleft palates in humans. Our previous work demonstrated that Pax9-dependent Wnt signaling is critical for the growth and fusion of palatal shelves. We showed that controlled intravenous delivery of small molecule Wnt agonists specifically blocks the action of Dkks (inhibitors of Wnt signaling) and corrects secondary palatal clefts in Pax9-/- mice. While these data underscore the importance of the functional upstream relationship of Pax9 to the Wnt pathway, not much is known about how the genetic nature of Pax9's interactions in vivo and how it modulates the actions of these downstream effectors during palate formation. Results Here, we show that the genetic reduction of Dkk1 during palatogenesis corrected secondary palatal clefts in Pax9-/- mice with restoration of Wnt signaling activities. In contrast, genetically induced overexpression of Dkk1 mice phenocopied the defects in tooth and palate development visible in Pax9-/- strains. Results of ChIP-qPCR assays showed that Pax9 can bind to regions near the transcription start sites of Dkk1 and Dkk2 as well as the intergenic region of Wnt9b and Wnt3 ligands that are downregulated in Pax9-/- palates. Conclusions Taken together, these data suggest that the molecular mechanisms underlying Pax9's role in modulating Wnt signaling activity likely involve the inhibition of Dkk expression and the control of Wnt ligands during palatogenesis.

The present study aimed to evaluate if genetic variants in PAX9, MSX1, TGFα, FGF3, FGF10, FGF13, GLI2 and GLI3 are involved in TS of permanent teeth.Pretreatment dental records from orthodontic patients were assessed prior to recruitment. Patients with tooth agenesis and congenital anomalies (including oral cleft) and/or syndromes were excluded. Dental casts were used to measure the maximum crown dimensions of all fully erupted permanent teeth except second and third molars in mesiodistal direction. Teeth with caries, occlusal wear, mesiodistal restorations, and obvious deformities were not evaluated. Genomic DNA samples were used for genotyping. The allelic discrimination of 13 genetic variants was performed. The associations between TS and genotype were analyzed by linear regression, adjusted by gender at a significance level of p ≤ 0.05.Genetic polymorphisms in the tooth agenesis-related genes studied here were associated with increased and decreased TS, in both maxilla and mandible (p 0.05).This study reported associations of novel tooth agenesis-related gene variants with permanent tooth size variations.The presence of some genetic variants could allow the prediction of permanent tooth size.

Background: Paired-box gene 9 ( PAX9) mutation is potentially associated with impaction in some patient populations. Here, we analyzed the relationship between PAX 9 polymorphism and the occurrence of maxillary canine impaction. Methods: Patients with and without maxillary canine impaction were selected based on specific inclusion criteria, and samples of genomic DNA were obtained from a buccal mucosa swab. DNA was amplified by polymerase chain reaction and sequenced for further bioinformatics analysis to identify single nucleotide polymorphism (SNP) genotypes. Genotype and allele counting was performed in both case and control groups prior to conducting statistical analysis. Results: Four SNPs were identified in patients with maxillary canine impaction, with relative confidence determined based on chromatogram-peak assessment. All SNPs were located in exon 3 of PAX 9 and in the region sequenced by the primer pair −197Fex3 and +28Rex3. Three of the SNPs (rs375436662, rs12881240, and rs4904210) were reported previously and are annotated in NCBI (dbSNP version 150), whereas another SNP mapped to chromosome 14 has not been reported. Patients with a CC genotype at SNP 3 [odds ratio (OR): 2.61 vs. TT; 1.28 vs. CT] and a CC genotype at SNP 4 [OR: 0.71 vs. GG; 0.79 vs. CG] were more likely to have maxillary canine impaction. Conclusions: These results demonstrated that the presence of SNPs 3 and 4 is associated with increased likelihood of suffering from maxillary canine impaction.

Objective: Tooth agenesis is one of the most common craniofacial developmental anomalies. In hypodontia, one to five teeth are missing, whereas oligodontia refers to the absence of at least six teeth, excluding the third molars. Mutations in several genes including MSX₁, PAX₉, AXIN₂, and WNT₁₀A have been shown to cause non-syndromic tooth agenesis. Regional odontodysplasia (RO), also known as “ghost teeth,” is a rare developmental anomaly of tooth formation affecting both dentitions. Some possible causes of RO have been suggested, yet the etiology remains unknown. Because the phenotypes of both oligodontia and RO co-occur in one Finnish family, the aim here was to investigate the genetic etiology of the two conditions. Materials and methods: A mutation screening of the genes MSX₁, PAX₉, AXIN₂, and WNT₁₀A was performed for the family members of a RO patient and family history of oligodontia. Results: An initiation codon mutation of the PAX₉ gene was found in the proband and segregating with oligodontia in the family. Conclusions: The etiology of regional odontodysplasia (RO) may be genetic and the same genes can be involved both in RO and tooth agenesis. Clinical relevance: Our results give new insights into the etiology of regional odontodysplasia, yet further results are needed.

Objective Mutations in the EDA gene, encoding the epithelial morphogen ectodysplasin-A, can result in different but overlapping phenotypes. Therefore the aim of the study was to search for etiological variations of EDA and other candidate genes in two unrelated Egyptian male children with sporadic non-syndromic tooth agenesis (NTA) and hypohidrotic ectodermal dysplasia (HED). Design Direct sequencing of the coding regions including exon-intron boundaries of EDA, MSX1, PAX9, WNT10A and EDAR was performed in probands and their available family members. Results Two etiological mutations were found in the EDA coding region. The patient with NTA in both deciduous and permanent dentition was a carrier of a novel in-frame deletion situated in the short collagenous domain (c.663-680delTCCTCCTGGTCCTCAAGG, p.222-227delPPGPQG). The second mutation, located outside the minimal furin consensus motif (c.463C>T, p.Arg155Cys, rs132630312), was identified in the patient exhibiting all typical features of HED. The identified EDA mutations were not detected in probands’ family members as well as in 188 unrelated control individuals. No pathogenic variants were found in the MSX1, PAX9, WNT10A and EDAR genes. Conclusion Our results increase the knowledge of the spectrum of EDA mutations and confirm that this gene is an important candidate gene for two developmental diseases sharing the common feature of the congenital lack of teeth. In addition, these results can support the hypothesis that X-linked HED and EDA-related NTA are the same disease with different degrees of severity.

Tooth agenesis in human being is the most common congenital anomaly associated with dental development. Mutations in many genes such as MSH homeobox 1 (MSX1), paired box gene 9 (PAX9), ectodysplasin A (EDA) and EDA receptor (EDAR) have been associated with familial form of this condition. However, in large majority of patients, genetic cause could not be identified. The primary aim of present study was to identify the causative mutation(s) in these genes in Saudi Arabian families diagnosed with non-syndromic form of disease. Direct sequencing of coding regions, including exon-intron boundaries of these genes was carried out. All identified nucleotide variations were also tested to exclude possibility of being rare polymorphisms. The sequence analysis of exons and exon-intronic regions of these genes revealed five new mutations that include four in MSX1, one in PAX9 and one single nucleotide polymorphism (SNP) in majority of the patients in MMP20. One novel mutation in exon 1 of MSX1 gene (5354C > G; A40G) was found in three patients. In addition, another novel mutation was detected in two patients in exon 3 (PAX9) as g.10672A > T which changes asparagine to isoleucine at position 40. These mutations were not found in any of the control subjects. A single SNP in MMP20 genes (g.5066A > C) that changes lysine to threonine at position 18 was found in 10% controls as well. Our results for the first time demonstrates that mutations in MSX1 gene might play an important role in hypodontia cases involving pre-molars and is a risk factor for this ethnic population mainly of Arabs and is first report linking these mutations with tooth agenesis.

Tooth agenesis and tumor are two totally different diseases occurring at different ages. In the past 10 years, more and more evidences suggested there was a relationship between them. High prevalence of breast, colon, lung, and ovary tumor was observed in tooth agenesis patients. But it is still controversial. Therefore, to have a greater understanding of the possible association, a critical review on molecular association for genes involving tooth agenesis and tumorigenesis is necessary. In this current review, we summarized the reported cases of tooth agenesis with different kinds of tumors and the molecular relationship between these two diseases through causative genes. The results indicated tooth agenesis might be a prospective predictive marker for tumor. Through this review, we want to draw more attention on this topic and hope it will be an effective way to predict the risk of tumor.

Molar-incisor hypomineralization (MIH) is a condition that is defined based on its peculiar clinical presentation. Reports on the etiology of the condition and possible risk factors are inconclusive and the original suggestion that MIH is an idiopathic condition is often cited. Our group was the first to suggest MIH has a genetic component that involves genetic variation in genes expressed during dental enamel formation. In this report, we provide a rationale to explain the preferential affection of molars and incisors. We suggest that MIH is a genetic condition based on its prevalence, which varies depending on the geographic location, and the evidence that on occasion second primary molars, permanent canines, and premolars can show signs of hypomineralization of enamel when molars and incisors are affected.