Novel Approach of Mandibular Distraction to Avoid Tracheostomy in KAT6B-related Gene Disorders.

Previously, severe upper airway obstruction in patients with retrognathia and glossoptosis has been managed with tracheostomy. However, tracheostomy is associated with significant morbidity. In recent years, mandibular distraction has become an alternative management strategy in infants, but these applications have been limited to patient populations with retrognathia and glossoptosis. The authors present 2 unique cases of patients with KAT6B-related gene disorders, who present with a paradox of tongue-based airway obstruction in the absence of retrognathia. In both cases mandibular distraction osteogenesis with an obliquely oriented vector was successfully performed and both children avoided the need for tracheostomy.

p75NTR-/- mice exhibit an alveolar bone loss phenotype and inhibited PI3K/Akt/ß-catenin pathway.

OBJECTIVES: The aim of this study was to investigate the role of p75 neurotrophin receptor (p75NTR) in regulating the mouse alveolar bone development and the mineralization potential of murine ectomesenchymal stem cells (EMSCs). Moreover, we tried to explore the underlying mechanisms associated with the PI3K/Akt/ß-catenin pathway. MATERIALS AND METHODS: p75NTR knockout (p75NTR-/- ) mice and wild-type (WT) littermates were used. E12.5d p75NTR-/- and WT EMSCs were isolated in the same pregnant p75NTR-/+ mice from embryonic maxillofacial processes separately. Mouse alveolar bone mass was evaluated using micro-CT. Differential osteogenic differentiation pathways between p75NTR-/- and WT EMSCs were analysed by RNA-sequencing. The PI3K inhibitor LY294002 and PI3K agonist 740Y-P were used to regulate the PI3K/Akt pathway in EMSCs. p75NTR overexpression lentiviruses, p75NTR knock-down lentiviruses and recombined mouse NGF were used to transfect cells. RESULTS: The alveolar bone mass was found reduced in the p75NTR knockout mouse comparing to the WT mouse. During mineralization induction, p75NTR-/- EMSCs displayed decreased osteogenic capacity and downregulated PI3K/Akt/ß-catenin signalling. The PI3K/Akt/ß-catenin pathway positively regulates the potential of differential mineralization in EMSCs. The promotive effect of p75NTR overexpression can be attenuated by LY294002, while the inhibitory effect of p75NTR knock-down on Runx2 and Col1 expression can be reversed by 740Y-P. CONCLUSION: Deletion of p75NTR reduced alveolar bone mass in mice. P75NTR positively regulated the osteogenic differentiation of EMSCs via enhancing the PI3K/Akt/ß-catenin pathway.

Symptomatic Mandibular Fibrous Dysplasia With Concurrent Triple X- and Premutation Stage Fragile-X-Syndrome: Case Report With Short Literature Survey.

BACKGROUND: Certain constitutive chromosomal abnormalities of the human X chromosome are relatively common in conspicuous neuropsychiatric findings. Although tumors or tumor-like lesions are occasionally reported in diseases of the X chromosome, they are numerically negligible, for example, in aneuploidy such as the triple X syndrome (TXS). CASE REPORT: A 16-year-old female patient with a known TXS and premutation stage of fragile X syndrome was referred by her dentist for diagnosis and treatment of unilateral cheek swelling. The examination of the psychologically conspicuous patient revealed a unilateral mandibular tumor with dysesthesia of the mental nerve. Surgical removal of soft, crumbly spongiosa over the nerve canal resulted in sufficient pressure release of the constricted nerve and restoration of epicritic sensitivity. Imaging findings and histological and molecular genetic examination revealed monostotic craniofacial fibrous dysplasia. CONCLUSION: Although the data in the literature do not give reason to suppose an accumulation of neoplasms in TXS, a numb chin syndrome should be a reason for detailed diagnostics. Careful diagnosis allows for customized therapy. This is the first report on the coincidence of TXS, fragile X syndrome, and fibrous dysplasia in a single individual.

Primary aneurysmal bone cyst of the mandibular condyle with USP6-CDH11 fusion.

Primary aneurysmal bone cyst (ABC) is a cystic bone neoplasm characterized by disease-defining gene fusions involving the USP6/Tre2 gene. The literature describing gnathic ABC is limited. This case report describes a 27-year-old man presenting with a long-standing left-sided facial asymmetry. Multi-detector computed tomography imaging demonstrated a large expansile lesion positioned within the left condylar head. The lesion was biopsied and resected. The specimen showed a giant cell-rich cystic neoplasm, with fibrous tissue lined by multinucleated giant cells. Next-generation sequencing confirmed the presence of a USP6-CDH11 fusion gene, consistent with classification as a primary ABC, the first reported to be translocation-positive in the head of the mandibular condyle.

Bilateral Central Giant Cell Granuloma of the mandibular angle in three females from the same family.

In literature there are few reports about multiple CGCG. But this is the first report of bilateral CGCG of the mandibular angles in three females from the same family.This report describes three cases of females from the same family - a mother and two young daughters - with bilateral CGCG in their jaw angles. All the lesions were surgically removed and the histopathologic diagnosis was always identical: giant cell central granulomas, with patterns that were absolutely superimposable between them and with that of the mother.The hypothesis is that this presentation of CGCG may be defined as hereditary bilateral CGCG of the mandibular angles (or also, cherubism-like lesions).

BMAL1 deficiency promotes skeletal mandibular hypoplasia via OPG downregulation.

OBJECTIVES: Skeletal mandibular hypoplasia (SMH), a common type of developmental deformities, results in impaired aesthetics of facial profile, occlusal dysfunction and poor life quality. In this study, BMAL1 deficiency leads to SMH formation, and we aim to investigate the mechanism by which BMAL1 deficiency induces SMH. MATERIALS AND METHODS: Circadian rhythm-disordered mouse models were constructed by placing animals in a jet lag schedule of 6-h light advance every 7 days for 4 or 8 weeks. The OPG expression was evaluated by histomorphometry, immunohistochemistry and western blot analysis. The mechanism by which BMAL1 affects OPG expression was investigated by chromatin immunoprecipitation and luciferase reporter assays. The phenotypes caused by BMAL1 knockout can be rescued by exogenous supplementation with OPG. RESULTS: We demonstrate that the expressions of BMAL1 and OPG decreased in SMH patients. Circadian rhythm-disordered mice and Bmal1-/- mice exhibited decreased expression of OPG, reduced bone mass and bone size of mandibles. Our results revealed that BMAL1 bound directly to the Opg promoter and upregulated its expression, thus inhibiting osteoclast differentiation. BMAL1 deficiency increased osteoclast differentiation by downregulating OPG expression. In vitro, the enhancement effect of osteoclast differentiation caused by BMAL1 knockdown was significantly reversed by exogenous supplementation with OPG. Importantly, bone loss caused by BMAL1 knockout can be partially reversed by injecting OPG Intraperitoneally. CONCLUSIONS: These results indicate that the circadian clock plays a critical role in the growth and development of mandible by regulating OPG expression, and present a potential therapeutic strategy to prevent SMH.

Direct evidence for the age-dependent demise of GNAS-mutated cells in oral fibrous dysplasia.

OBJECTIVE: Fibrous dysplasia (FD) is a benign bone disease characterized by fibro-osseous lesions. FD is caused by somatic mutations in the gene, guanine nucleotide-binding protein, alpha stimulating activity polypeptide 1 (GNAS), which encodes the G protein subunit, Gsα. FD manifests early in life, but the growth of lesions usually ceases in adulthood. FD lesions often exhibit somatic mutation mosaicism. In this study, the relationship between lesion growth and mutation prevalence within a lesion was investigated. DESIGN: Lesions from five FD patients were characterized by radiographical, histological and immunohistochemical methods. To accurately calculate the prevalence of mutations within lesions, GNAS codon 201 in genomic DNA isolated from fresh surgical FD specimens was sequenced. RESULTS: Uniquely, a lesion in one 46-year-old patient was still growing, enabling simultaneous analysis of both stable-old and active-new FD lesions in the same patient. Immunohistochemical analysis indicated that a newer, proximal lesion was growing while an older, distal lesion was not. The mutation prevalence differed between these lesions; it was low in the old and high in the new lesion. Thus, the frequency of mutated cells had decreased in the older lesion. CONCLUSIONS: This is the first direct evidence for the age-dependent demise of mutated cells in FD, helping to explain why FD lesion growth generally ceases in adulthood.

BMAL1 Deficiency Contributes to Mandibular Dysplasia by Upregulating MMP3.

Skeletal mandibular hypoplasia (SMH), one of the common types of craniofacial deformities, seriously affects appearance, chewing, pronunciation, and breathing. Moreover, SMH is prone to inducing obstructive sleep apnea syndrome. We found that brain and muscle ARNT-like 1 (BMAL1), the core component of the molecular circadian oscillator, was significantly decreased in mandibles of juvenile SMH patients. Accordingly, SMH was observed in circadian-rhythm-disrupted or BMAL1-deficient mice. RNA sequencing and protein chip analyses suggested that matrix metallopeptidase 3 (MMP3) is the potential target of BMAL1. Interestingly, in juvenile SMH patients, we observed that MMP3 was obviously increased. Consistently, MMP3 was upregulated during the whole growth period of 3-10 weeks in Bmal1-/- mice. Given these findings, we set out to characterize the underlying mechanism and found BMAL1 deficiency enhanced Mmp3 transcription through activating p65 phosphorylation. Together, our results provide insight into the mechanism by which BMAL1 is implicated in the pathogenesis of SMH.

Intraosseous inflammatory myofibroblastic tumor of the mandible with a novel ATIC-ALK fusion mutation: a case report.

BACKGROUND: Inflammatory myofibroblastic tumor (IMT) is a rare low-grade malignant neoplasm with a predilection for children and young adults, and typically arises in the lung, abdominopelvic region, and retroperitoneum. IMTs in the maxillofacial region are extreme rare. Approximately 50% of IMT harbor rearrangements of the anaplastic lymphoma kinase (ALK) gene at 2p23 with various fusion partners. CASE PRESENTATION: We herein report a case of intraosseous IMT of the mandible with a novel ATIC-ALK fusion. Tooth 43 did not erupt after the loss of tooth 83 in an 11-year-old girl with no previous history of trauma. Panoramic tomography showed a unilocular radiolucent lesion in the right anterior mandible resorbing the root of tooth 42 and the medial side of the root of tooth 44. Computed tomography revealed a well- circumscribed 3-cm osteolytic lesion of the right anterior mandible eroding the buccal cortical plate. The entire lesion was curetted out. A histopathological examination revealed the proliferation of plump spindle cells with a storiform architecture and lymphocytes scattered around spindle cells. The spindle cells showed diffuse cytoplasmic staining for ALK by immunohistochemistry. A fluorescence in situ hybridization analysis revealed the translocation of a part of the ALK gene locus at chromosome 2p23. A rapid amplification of cDNA ends analysis confirmed the rearrangement of ALK and identified ATIC as a partner of this ALK fusion mutant. CONCLUSION: To the best of our knowledge, this is the first case of intraosseous IMT of the mandible with a novel ATIC-ALK fusion. We also herein reviewed similar tumors reported in the literature.

First case of bilateral coronoid hyperplasia in monozygotic twin sisters-a new aetiological perspective?

BACKGROUND: Mandibular coronoid hyperplasia is a rare condition associated with gradual reduction in mouth opening. Its aetiology is unknown but increased temporalis activity, endocrine stimulus, trauma and familial causes have been proposed. CASE REPORT: In this article, we present a case of bilateral coronoid hyperplasia presenting with limited mouth opening in 16-year-old Caucasian twin sisters. DISCUSSION: This report gives a new perspective to the aetiology of coronoid hyperplasia since it describes its occurrence in monozygotic twins and hence provides a strong argument in support of a genetic aetiology.

Recurrent multilocular mandibular giant cell granuloma in neurofibromatosis type 1: Evidence for second hit mutation of NF1 gene in the jaw lesion and treatment with curettage and bone substitute materials.

Giant cell granuloma (GCG) of the jaw is a rare, well-known feature of neurofibromatosis type 1 (NF1), an inborn multisystem disorder. Recently, the development of GCG in NF1 was attributed to second hit mutations in the NF1 gene. The treatment of GCG is pragmatic with a preference for local curettage of lytic osseous areas. This report describes the surgical therapy of an NF1-affected female with multilocular mandibular GCG and hypodontia who additionally suffered from a brain tumour and Hashimoto's thyroiditis. Although local recurrence of GCG was noted, augmentation of the curetted cavities with a bone substitute in successive interventions successfully restored the extensive periradicular local defects and stabilised the teeth. A meticulous in vitro study of the GCG specimen revealed a second hit mutation in the NF1 gene in the GCG spindle-cells. This study contributes to the increasing knowledge of the molecular basis for GCG in the jaw of NF1 patients, indicating that it is a neoplasm.

Targeting Atp6v1c1 Prevents Inflammation and Bone Erosion Caused by Periodontitis and Reveals Its Critical Function in Osteoimmunology.

Periodontal disease (Periodontitis) is a serious disease that affects a majority of adult Americans and is associated with other systemic diseases, including diabetes, rheumatoid arthritis, and other inflammatory diseases. While great efforts have been devoted toward understanding the pathogenesis of periodontitis, there remains a pressing need for developing potent therapeutic strategies for targeting this pervasive and destructive disease. In this study, we utilized novel adeno-associated virus (AAV)-mediated Atp6v1c1 knockdown gene therapy to treat bone erosion and inflammatory caused by periodontitis in mouse model. Atp6v1c1 is a subunit of the V-ATPase complex and regulator of the assembly of the V0 and V1 domains of the V-ATPase complex. We demonstrated previously that Atp6v1c1 has an essential function in osteoclast mediated bone resorption. We hypothesized that Atp6v1c1 may be an ideal target to prevent the bone erosion and inflammation caused by periodontitis. To test the hypothesis, we employed AAV RNAi knockdown of Atp6v1c1 gene expression to prevent bone erosion and gingival inflammation simultaneously. We found that lesion-specific injection of AAV-shRNA-Atp6v1c1 into the periodontal disease lesions protected against bone erosion (>85%) and gingival inflammation caused by P. gingivalis W50 infection. AAV-mediated Atp6v1c1 knockdown dramatically reduced osteoclast numbers and inhibited the infiltration of dendritic cells and macrophages in the bacteria-induced inflammatory lesions in periodontitis. Silencing of Atp6v1c1 expression also prevented the expressions of osteoclast-related genes and pro-inflammatory cytokine genes. Our data suggests that AAV-shRNA-Atp6v1c1 treatment can significantly attenuate the bone erosion and inflammation caused by periodontitis, indicating the dual function of AAV-shRNA-Atp6v1c1 as an inhibitor of bone erosion mediated by osteoclasts, and as an inhibitor of inflammation through down-regulation of pro-inflammatory cytokine expression. This study demonstrated that Atp6v1c1 RNAi knockdown gene therapy mediated by AAV-shRNA-Atp6v1c1 is a promising novel therapeutic approach for the treatment of bone erosion and inflammatory related diseases, such as periodontitis and rheumatoid arthritis.

Cytogenetics of central giant cell granuloma of the mandible.

PURPOSE: Central giant cell granuloma is a benign entity that commonly occurs in the mandible and maxilla. It is usually treated by surgical excision, varying from curettage to en bloc resection. Because the entity is more common in diseases such as neurofibromatosis, a genetic element may be involved in its pathogenesis. Cytogenetic studies of central giant cell granuloma affecting bone are rare, and to the authors' knowledge, there are none reported in the literature for central giant cell granuloma of the mandible. MATERIALS AND METHODS: The authors investigated the cytogenetic profile of a case occurring in the mandible. Fresh biopsy tissue was minced and cultured in RPMI-1640 medium. Cells were fixed and stained, and cytogenetic analysis was performed according to standard procedures. RESULTS: A clone with t(1;17;18) and other random numerical chromosomal changes was found. CONCLUSIONS: The significance of these findings in diagnosis and prognosis is currently unclear and further karyotyping studies are needed to more fully understand this tumor.

Gardner's syndrome: a clinical and genetic study of a family.

OBJECTIVE: Gardner syndrome (GS) is an autosomal dominant genetic disorder with almost complete penetrance (80%) and variable expression. GS is a variant of familial adenomatous polyposis and characterized by extracolonic manifestations including osteomas and soft tissue tumors (desmoid tumors, epidermoid cysts). We describe clinical and surgical approaches in a family in which the genetic disorder was diagnosed in 3 generations. STUDY DESIGN: The studied family underwent clinical history and instrumental and genomic studies. Two members of this family, affected with GS, underwent surgery for skeletal osteomas. RESULTS: The patients that we treated with clinical-instrumental monitoring for a period of 5 years had no major disturbances of the stomatognathic system and no clinical signs of pathology of the gastrointestinal tract, eyes, or endocrine systems. CONCLUSIONS: The orofacial complex disorders are exclusively functional and esthetic, concerning primarily the stomatognathic system. We had no cases of malignant transformation of osteomatosis lesions. Clinical sequelae are manly facial eumorphy and occlusion problems of the temporomandibular joint.

Dental abnormalities in a mouse model for craniometaphyseal dysplasia.

Mice carrying a knock-in mutation (Phe377del) in the Ank gene replicate many skeletal characteristics of human craniometaphyseal dysplasia, including hyperostotic mandibles. Ank (KI/KI) mice have normal morphology of erupted molars and incisors but excessive cementum deposition with increased numbers of Ibsp- and Dmp1-positive cells on root surfaces. The cervical loops of adult Ank (KI/KI) lower incisors are at the level of the third molars, while they are close to the mandibular foramen in Ank (+/+) mice. Furthermore, Ank (KI/KI) incisors show decreased eruption rates, decreased proliferation of odontoblast precursors, and increased cell apoptosis in the stellate reticulum. However, their capability for continuous elongation is not compromised. Quantification of TRAP-positive cells in the apical ends of Ank (KI/KI) incisors revealed decreased osteoclast numbers and osteoclast surfaces. Bisphosphonate injections in Ank (+/+) mice replicate the Ank (KI/KI) incisor phenotype. These results and a comparison with the dental phenotype of Ank loss-of-function mouse models suggest that increased cementum thickness may be caused by decreased extracellular PPi levels and that the incisor phenotype is likely due to hyperostosis of mandibles, which distinguishes Ank (KI/KI) mice from the other Ank mouse models.

p53 expression and mutation analysis of odontogenic cysts with and without dysplasia.

OBJECTIVE: Overexpression of p53 protein is well described in odontogenic cystic lesions (OCLs), including those with epithelial dysplasia; however, most p53 antibodies stain both wild-type and mutated p53 protein and may not reflect genotype. Direct sequencing of the p53 gene has not identified mutations in OCLs with dysplasia. The purpose of this study was to determine the molecular basis of p53 expression in several types of OCLs with and without dysplasia. METHODS: The study material comprised 13 OCLs: odontogenic keratocyst (n = 5), orthokeratinized odontogenic cyst (n = 5), dentigerous cyst (n = 2), lateral periodontal cyst (n = 1), and unspecified developmental odontogenic cyst (UDOC) (n = 1). Five of these had features of mild or moderate epithelial dysplasia. One intraosseous squamous cell carcinoma (SCC) that was believed to have arisen from an antecedent dysplastic orthokeratinized OC was also included. Immunohistochemistry was performed using the DO7 monoclonal antibody that recognizes wild-type and mutated p53. DNA was extracted from microdissected tissue for all samples and exons 4 to 8 of the p53 gene direct sequenced. RESULTS: In 4 of 5 OCLs with dysplasia there was strong nuclear staining of basal and suprabasal cells. In all cases without dysplasia, nuclear expression in basal cells was either negative or weak and was absent in suprabasal cell nuclei. A mutation in exon 6 of the p53 gene (E224D) was identified in both the dysplastic orthokeratinized OC and the subsequent intraosseous SCC. CONCLUSIONS: OCLs with features of dysplasia show increased expression of p53 protein that does not reflect p53 mutational status. One dysplastic OC shared the same p53 mutation with a subsequent intraosseous SCC, indicating that p53 mutation may be associated with malignant transformation in this case.

New approach to analyze genetic and clinical data in bisphosphonate-induced osteonecrosis of the jaw.

OBJECTIVES: Osteonecrosis of the jaw (ONJ) is a major complication associated with long-term use of bisphosphonates (BP). We aimed to investigate the effect of CYP2C8 rs1934951 SNP and its relationship to a number of clinical and biochemical factors in 46 Hungarian subjects with bisphosphonate-induced ONJ. METHODS: Blood samples were collected from each subject and genomic DNA was extracted. SNP analysis of CYP2C8 gene was carried out by predesigned TaqMan primer/probe sets. The genetic data together with clinical and biochemical variables were evaluated by chi-square test, logistic regression, and principal component analysis (PCA). RESULTS: The risk of mandibular localization of ONJ was 19.2-fold higher in subjects with AG genotype than in normal GG genotype. PCA revealed strong positive correlations between maxillar localization of ONJ and a group of variables including intravenous BP application and serum lipid markers. Mandibular localization of ONJ was correlated positively with serum calcium, 25-hydroxy-vitamin D and PTH levels, oral BP application, and the length of BP therapy. The degree of the disease and the number of recurrences were correlated with the application of hormone-deprivation therapy for breast cancer patients. CONCLUSION: The statistical approach applying PCA to our data may contribute to the better understanding of factors playing role in the development of bisphosphonate-induced ONJ.

Keratocystic odontogenic tumour (KCOT)--a cyst to a tumour.

PURPOSE: The World Health Organization (WHO) has reclassified 'odontogenic keratocyst' (OKC) to 'keratocystic odontogenic tumour' (KCOT) in 2005. Currently, this tumour is classified as a benign neoplasm of odontogenic origin and not as a cyst. This article reviews and discusses history, classification scheme, aetiology and pathogenesis, molecular and genetic basis, incidence, epidemiology and site, clinical features, imaging, histopathology, immunohistochemistry, treatment options, prognosis, recurrence and malignant transformation of KCOT, with emphasis on understanding the basis of reclassification as 'keratocystic odontogenic tumour'. METHODS: A systematic search and review of the literature was carried out in the online database of the United States National Library of Medicine to identify eligible titles for the study. RESULTS: Current evidence suggests that the scientific community still continues to use the term 'odontogenic keratocyst' more favourably than 'keratocystic odontogenic tumour'. CONCLUSION: The online database search indicates that the scientific community still continues to use the term 'odontogenic keratocyst' more favourably than 'keratocystic odontogenic tumour'. At this juncture, where the terminology has changed from a cyst to a tumour, a thorough review of literature on KCOT is presented.