Gingival fibromatosis: clinical, molecular and therapeutic issues

Idiopathic gingival fibromatosis and primary analysis of dominant bacteria in subgingival biofilm: a case report

Idiopathic gingival fibromatosis (IGF), a rare fibroproliferative disease of unknown etiology, affects gingival tissue and has substantial adverse effects on patients. Therefore, the pathogenesis of IGF requires more extensive and in-depth research. In this case, a patient with confirmed IGF underwent initial nonsurgical periodontal therapy and gingivectomy, and the prognosis was good. The patient had no loss of periodontal attachment but had a history of swelling and bleeding of the gingiva prior to fibrous enlargement, which prompted further investigation. We explored the patient's subgingival microbiome and found a high abundance of periodontal pathogens. Gingival tissue biopsy revealed abundant fibrous tissue containing multiple inflammatory cell infiltrates. These results suggest that gingival inflammation secondary to periodontal pathogens can contribute to IGF onset.

A recurrent KCNK4 variant in a dominant pedigree with hypertrichosis and gingival fibromatosis syndrome: Variable phenotypic expressivity and insights on patients' dental management

Abnormal hyperpolarization of the KCNK4 gene, expressed in the nervous system, brain, and periodontal ligament fibroblasts, leads to impaired neurotransmitter sensitivity, cardiac arrhythmias, and endocrine dysfunction, as well as, progressive cell proliferation. De novo gain of function variants in the KCNK4 gene were reported to cause a recognizable syndrome characterized by facial dysmorphism, hypertrichosis, epilepsy, intellectual/developmental delay, and gingival overgrowth (FHEIG, OMIM# 618381). FHEIG is extremely rare with only three reported cases in the literature. Herein, we describe the first inherited KCNK4 variant (c.730G>C, p.Ala244Pro) in an Egyptian boy and his mother. Variable phenotypic expressivity was noted as the patient presented with the full-blown picture of the syndrome while the mother presented only with hypertrichosis and gingival overgrowth without any neurological manifestations. The c.730G>C (p.Ala244Pro) variant was described before in a single patient and when comparing the phenotype with our patient, a phenotype-genotype correlation seems likely. Atrial fibrillation and joint laxity are new associated findings noted in our patient extending the clinical phenotype of the syndrome. Dental management was offered to the affected boy and a dramatic improvement was noted as the patient regained his smile, restored the mastication function, and resumed his psychological stability.

Identification of optimal feature genes in patients with thyroid associated ophthalmopathy and their relationship with immune infiltration: a bioinformatics analysis

Background

Thyroid associated ophthalmopathy (TAO) is an organ-specific autoimmune disease that has a significant impact on individuals and society. The etiology of TAO is complicated and poorly understood. Thus, the goal of this study was to use bioinformatics to look into the pathogenesis of TAO and to identify the optimum feature genes (OFGs) and immune infiltration patterns of TAO.

Methods

Firstly, the GSE58331 microarray data set was utilized to find 366 differentially expressed genes (DEGs). To find important modular genes, the dataset was evaluated using weighted gene coexpression network analysis (WGCNA). Then, the overlap genes of major module genes and DEGs were further assessed by applying three machine learning techniques to find the OFGs. The CIBERSORT approach was utilized to examine immune cell infiltration in normal and TAO samples, as well as the link between optimum characteristic genes and immune cells. Finally, the related pathways of the OFGs were predicted using single gene set enrichment analysis (ssGSEA).

Results

KLB, TBC1D2B, LINC01140, SGCG, TMEM37, and LINC01697 were the six best feature genes that were employed to create a nomogram with high predictive performance. The immune cell infiltration investigation revealed that the development of TAO may include memory B cells, T cell follicular helper cells, resting NK cells, macrophages of type M0, macrophages of type M1, resting dendritic cells, active mast cells, and neutrophils. In addition, ssGSEA results found that these characteristic genes were closely associated with lipid metabolism pathways.

Conclusion

In this research, we found that KLB, TBC1D2B, LINC01140, SGCG, TMEM37, and LINC01697 are intimately associated with the development and progression of TAO, as well as with lipid metabolism pathways.

Double heterozygous pathogenic mutations in KIF3C and ZNF513 cause hereditary gingival fibromatosis

Hereditary gingival fibromatosis (HGF) is a rare inherited condition with fibromatoid hyperplasia of the gingival tissue that exhibits great genetic heterogeneity. Five distinct loci related to non-syndromic HGF have been identified; however, only two disease-causing genes, SOS1 and REST, inducing HGF have been identified at two loci, GINGF1 and GINGF5, respectively. Here, based on a family pedigree with 26 members, including nine patients with HGF, we identified double heterozygous pathogenic mutations in the ZNF513 (c.C748T, p.R250W) and KIF3C (c.G1229A, p.R410H) genes within the GINGF3 locus related to HGF. Functional studies demonstrated that the ZNF513 p.R250W and KIF3C p.R410H variants significantly increased the expression of ZNF513 and KIF3C in vitro and in vivo. ZNF513, a transcription factor, binds to KIF3C exon 1 and participates in the positive regulation of KIF3C expression in gingival fibroblasts. Furthermore, a knock-in mouse model confirmed that heterozygous or homozygous mutations within Zfp513 (p.R250W) or Kif3c (p.R412H) alone do not led to clear phenotypes with gingival fibromatosis, whereas the double mutations led to gingival hyperplasia phenotypes. In addition, we found that ZNF513 binds to the SOS1 promoter and plays an important positive role in regulating the expression of SOS1. Moreover, the KIF3C p.R410H mutation could activate the PI3K and KCNQ1 potassium channels. ZNF513 combined with KIF3C regulates gingival fibroblast proliferation, migration, and fibrosis response via the PI3K/AKT/mTOR and Ras/Raf/MEK/ERK pathways. In summary, these results demonstrate ZNF513 + KIF3C as an important genetic combination in HGF manifestation and suggest that ZNF513 mutation may be a major risk factor for HGF.

Surgical treatment of hereditary gingival fibromatosis by diode laser: Report of five rare cases in the same family

The pathogenesis of hereditary gingival fibromatosis (HGF) is largely unknown; however, the removal of excess tissue may often be necessary as it often causes aesthetic and functional problems. Gingivectomy is usually a treatment option that can be performed using a scalpel, cryotherapy, electrosurgery, or laser. This paper aims to evaluate the results of HGF treatments using a diode laser of five people from the same family. Three members of a family of five (two females and three males; 9-36 years old) underwent gingivectomy with a 3 W 300-micron fiber-tipped diode laser (Doctor Smile, Vicenza, Italy) at 810 nm wavelength. While all teeth of one member were extracted, the other member refused treatment. Relapse occurred in three members due to poor oral hygiene. The diode laser was reapplied and oral hygiene instructions were repeated. Patients were followed during the postoperative period for up to two years. HGF is a rare condition that clinicians should pay attention to in the diagnosis, treatment, and follow-ups. Since recurrences are due to dental plaque, oral hygiene instructions are essential and compliance is mandatory. Although there are many treatment approaches, the diode laser is the most indicated method due to many advantages such as providing a bloodless and more sterile operation field, performing an atraumatic surgery, ensuring earlier and ideal recovery, and minimizing postoperative pain.

Drug-Induced Gingival Overgrowth—Molecular Aspects of Drug Actions

Drug-induced gingival overgrowth (DIGO) is one of the side effects produced by therapeutic agents, most commonly phenytoin, nifedipine and cyclosporin A. However, the precise mechanism of DIGO is not entirely understood. A literature search of the MEDLINE/PubMed databases was conducted to identify the mechanisms involved in DIGO. The available information suggests that the pathogenesis of DIGO is multifactorial, but common pathogenic sequelae of events emerge, i.e., sodium and calcium channel antagonism or disturbed intracellular handling of calcium, which finally lead to reductions in intracellular folic acid levels. Disturbed cellular functions, mainly in keratinocytes and fibroblasts, result in increased collagen and glycosaminoglycans accumulation in the extracellular matrix. Dysregulation of collagenase activity, as well as integrins and membrane receptors, are key mechanisms of reduced degradation or excessive synthesis of connective tissue components. This manuscript describes the cellular and molecular factors involved in the epithelial–mesenchymal transition and extracellular matrix remodeling triggered by agents producing DIGO.

The paradigm of miRNA and siRNA influence in Oral-biome

Short nucleotide sequences like miRNA and siRNA have attracted a lot of interest in Oral-biome investigations. miRNA is a small class of non-coding RNA that regulates gene expression to provide effective regulation of post-transcription. On contrary, siRNA is 21-25 nucleotide dsRNA impairing gene function post-transcriptionally through inhibition of mRNA for homologous dependent gene silencing. This review highlights the application of miRNA in oral biome including oral cancer, dental implants, periodontal diseases, gingival fibroblasts, oral submucous fibrosis, radiation-induced oral mucositis, dental Pulp, and oral lichenoid disease. Moreover, we have also discussed the application of siRNA against the aforementioned disease along with the impact of miRNA and siRNA to the various pathways and molecular effectors pertaining to the dental diseases. The influence of upregulation and downregulation of molecular effector post-treatment with miRNA and siRNA and their impact on the clinical setting has been elucidated. Thus, the mentioned details on application of miRNA and siRNA will provide a novel gateway to the scholars to not only mitigate the long-lasting issue in dentistry but also develop new theragnostic approaches.

Periodontitis and Intra-Oral Plasmacytosis in a Noonan's Syndrome Patient

A 13-year-old female patient with Noonan's syndrome, intra-oral periodontitis, and associated periodontal lesions is presented in this case report. The patient suffered early onset severe molar pattern periodontitis and recurrent intra-oral inflammatory lesions, pyogenic granuloma, and plasmacytosis, which were excised and controlled using a strict oral hygiene protocol based on long-term use of chlorhexidine-based products as auxiliary aid to regular home care and brushing.

Expression of TGF-β and MMP-2 in hereditary gingival fibromatosis epithelial cells. A possible contribution of the epithelium to its pathogenesis

Background

Although the molecular mechanisms that cause the development of hereditary gingival fibromatosis are not fully understood, multiple theories have been suggested to clarify its pathogenesis. However, the overlying keratinocytes' function is poorly comprehended. This work aimed to investigate the expression of TGF-β and MMP-2 in hereditary gingival fibromatosis epithelial cells compared to the normal gingival epithelium to give an insight into the mechanism of the development of this condition.

Methods

Biopsies were obtained from 20 hereditary gingival fibromatosis patients and 20 healthy controls. Biopsies were stained immunohistochemically and statistically analyzed for MMP-2 and TGF-β expression.

Results

Regarding MMP-2, The hereditary gingival fibromatosis group recorded a higher mean value compared to the normal gingiva, with a mean difference of 3.29 ± 0.34. This difference was statistically significant (p = 0.00). Regarding TGF-β, a higher mean value was recorded in the HGF group compared to the normal gingiva, with a mean difference of 15.88 ± 1.05 The difference was statistically significant (p = 0.00). A strong positive correlation was detected between MMP-2 and TGF-β (R = 0.534, p = 0.015).

Conclusions

In hereditary gingival fibromatosis, the epithelium expresses higher levels of TGF-β and MMP-2 than normal gingival tissue. There was an evident positive correlation between MMP-2 and TGF-β. Our data suggest that the expression of TGF-β and MMP2 by epithelial cells of HGF may play a role in the epithelial-mesenchymal transition pathogenic pathway.

Identifying the focuses of hereditary gingival fibromatosis with bioinformatics strategies

OBJECTIVE

The objective of this study was to detect the undiscovered bioinformatics information about hereditary gingival fibromatosis and find focuses from published datasets.

METHODS

Two published datasets containing gingival tissue expression profiles of HGF and healthy groups were collected from GEO database. GSE4250 was utilized for cardinality analysis, including the differentially expressed gene analysis, enrichment analyses, hierarchical clustering analysis, and protein-protein interaction network. Key genes were obtained from the protein interaction network plot. GSE58482 was utilized for validation.

RESULTS

Analysis of the expression profiling by array, there were 785 genes (380 upregulated genes, 405 downregulated genes) expressed differentially between HGF gingival tissue and healthy gingival tissue. KEGG and GO enrichment analyses obtained candidate pathways. Differentially expressed genes were associated with activated pathways like skin barrier pathway and cornified envelope pathway. Repressed pathways included ion homeostasis pathway, receptor ligand activity pathway, and cell population proliferation pathway. Key genes such as F2R, TGM7, and MMP13 were confirmed with differential expression by external validation.

CONCLUSION

By bioinformatics approaches, we found new discoveries including several pathways and key genes. These discoveries deserve attention and research in the future.

Recurrent Gingival Lesions in a Pediatric Patient

We present the case of a 13-year-old girl who developed numerous gingival masses that recurred after two prior resections. Following the initial resection as a child, she reported that there was a period of resolution for several years before recurrence as a teenager. After the second resection, the masses recurred after 4 months. The lesions obscured the majority of her dentition and interfered with speech, eating, and oral hygiene. The patient underwent staged resection of the masses, and the wounds were allowed to heal by secondary intention. The histopathologic findings of the specimens were consistent with a diagnosis of peripheral ossifying fibroma, which is unusual as these are generally solitary lesions. We believe that this case brings attention to an underrecognized and atypical presentation of peripheral ossifying fibroma, and it should be considered in the differential diagnosis of multicentric gingival masses.

Non-Plaque Induced Diffuse Gingival Overgrowth: An Overview

Non-plaque induced diffuse gingival overgrowth represents a broad class of conditions caused by several etiological factors. The aim of this review is to highlight the most recent updates and classifications of all the existent gingival overgrowths. In addition, we highlighted the diagnostic pathway that should be employed in patients affected by gingival overgrowth. Gingival overgrowth can be related to syndromic diseases including a wide spectrum of genetic and chromosomal alterations. However, thanks to scientific sharing and the availability of genetic panels it is possible to obtain an accurate phenotypic identification of well-known syndromes and also to identify new ones. This narrative review shows that through rigid, strict diagnostic protocols, the work of the clinician is greatly facilitated, despite the wide variety of pathologies considered. In conclusion, the exchange of specialists’ competencies and the multidisciplinary management of these patients, are crucial to reach diagnosis and the correct clinical-therapeutic management.

Hereditary Gingival Fibromatosis and Developmental Anomalies: A Case Report

Hereditary gingival fibromatosis is the most common genetic form of gingival fibromatosis that develops as a slow, progressive, benign, localized, or generalized enlargement of the keratinized gingiva. It is a genetically heterogeneous disorder transmitted as an autosomal dominant or autosomal recessive trait or appears sporadically. Here, we report a case of a male patient with generalized gingival hyperplasia with great tissue extension to the palatal region, bilateral mandibular torus, bilateral exostosis in the maxillary posterior region, anterior open bite, and diastema in anterior maxilla and mandible teeth. The mucous membranes were healthy and normal colored, with pale pink gums and firm teeth upon palpation. Computed tomography also revealed images suggestive of supernumerary teeth. The patient reported that his mother and a maternal aunt have the same gingival condition. Considering the gingival characteristic, the patient's family history, and the absence of other possible etiological factors of gingival hyperplasia, the diagnostic hypothesis was hereditary gingival fibromatosis. The surgical removal of the enlarged tissue through gingivectomy with internal bevel, osteoplasty, and removal of supernumerary teeth with a subsequent filling of the surgical sites with platelet and leukocyte-rich fibrin membranes in the same surgical time presented good functional and aesthetic results for the young patient with hereditary gingival fibromatosis. It is a viable possibility for clinical management of similar cases.

Hereditary Gingival Fibromatosis: A Report of a Severe Case

Hereditary gingival fibromatosis (HGF) is an uncommon condition characterized by a benign, local, or diffuse gingival overgrowth. It may cover the teeth partially or totally, causing essential aesthetic, phonetic, and masticatory disorders. In this report, we discuss a case of an 11-year-old boy who presented with severe gingival enlargement. The diagnosis of HGF was made based on clinical examination and family history, with two of the patient’s brothers and his paternal aunt being affected with the same disease. The patient was managed with electrosurgery under general anesthesia.

A novel gene ZNF862 causes hereditary gingival fibromatosis

Hereditary gingival fibromatosis (HGF) is the most common genetic form of gingival fibromatosis which is featured as a localized or generalized overgrowth of gingivae. Currently two genes (SOS1 and REST), as well as four loci (2p22.1, 2p23.3–p22.3, 5q13–q22, and 11p15), have been identified as associated with HGF in a dominant inheritance pattern. Here, we report 13 individuals with autosomal-dominant HGF from a four-generation Chinese family. Whole-exome sequencing followed by further genetic co-segregation analysis was performed for the family members across three generations. A novel heterozygous missense mutation (c.2812G > A) in zinc finger protein 862 gene (ZNF862) was identified, and it is absent among the population as per the Genome Aggregation Database. The functional study supports a biological role of ZNF862 for increasing the profibrotic factors particularly COL1A1 synthesis and hence resulting in HGF. Here, for the first time we identify the physiological role of ZNF862 for the association with the HGF.

Clinics and genetic background of hereditary gingival fibromatosis

BACKGROUND

Hereditary gingival fibromatosis (HGF) is a rare condition characterized by slowly progressive overgrowth of the gingiva. The severity of overgrowth may differ from mild causing phonetic and masticatory issues, to severe resulting in diastemas or malposition of teeth. Both, autosomal-dominant and autosomal-recessive forms of HGF are described. The aim of this review is a clinical overview, as well as a summary and discussion of the involvement of candidate chromosomal regions, pathogenic variants of genes, and candidate genes in the pathogenesis of HGF. The loci related to non-syndromic HGF have been identified on chromosome 2 (GINGF, GINGF3), chromosome 5 (GINGF2), chromosome 11 (GINGF4), and 4 (GINGF5). Of these loci, pathogenic variants of the SOS-1 and REST genes inducing HGF have been identified in the GINGF and the GINGF5, respectively. Furthermore, among the top 10 clusters of genes ranked by enrichment score, ATP binding, and fibronectin encoding genes were proposed as related to HGF.

CONCLUSION

The analysis of clinical reports as well as translational genetic studies published since the late'90s indicate the clinical and genetic heterogeneity of non-syndromic HGF and point out the importance of genetic studies and bioinformatics of more numerous unrelated families to identify novel pathogenic variants potentially inducing HGF. This strategy will help to unravel the molecular  mechanisms as well as uncover specific targets for novel and less invasive therapies of this rare, orphan condition.

Case Report: A Case of Hereditary Gingival Fibromatosis With a High Level of Human β Defensins in Gingival Epithelium

Hereditary gingival fibromatosis [HGF, (MIM 135300)], a rare benign oral condition, has several adverse consequences such as aesthetic changes, malocclusion, speech impediments, and abnormal dentition. However, relatively few studies have addressed the beneficial effects of thick gingival tissues in resisting external stimuli. In this report, we present a unique case of a family affected by HGF that manifests as a ‘healthy’ gingiva. Human β-defensins (hBDs) are known to play a pivotal role in the clearance and killing of various microbes, and contribute to maintaining a healthy oral environment, which is currently emerging research area. However, the expression pattern and localisation of hBDs in patients with HGF have not yet been reported. hBD-2 and hBD-3 in the pedigree we collected had relatively elevated expression. High hBD levels in the gingival tissue of patients from the family may be beneficial in protecting oral tissue from external stimuli and promoting periodontal regeneration, but their role and the mechanisms underlying HGF need to be clarified.

Pathogenesis of Enamel-Renal Syndrome Associated Gingival Fibromatosis: A Proteomic Approach

The enamel renal syndrome (ERS) is a rare disorder featured by amelogenesis imperfecta, gingival fibromatosis and nephrocalcinosis. ERS is caused by bi-allelic mutations in the secretory pathway pseudokinase FAM20A. How mutations in FAM20A may modify the gingival connective tissue homeostasis and cause fibromatosis is currently unknown. We here analyzed conditioned media of gingival fibroblasts (GFs) obtained from four unrelated ERS patients carrying distinct mutations and control subjects. Secretomic analysis identified 109 dysregulated proteins whose abundance had increased (69 proteins) or decreased (40 proteins) at least 1.5-fold compared to control GFs. Proteins over-represented were mainly involved in extracellular matrix organization, collagen fibril assembly, and biomineralization whereas those under-represented were extracellular matrix-associated proteins. More specifically, transforming growth factor-beta 2, a member of the TGFβ family involved in both mineralization and fibrosis was strongly increased in samples from GFs of ERS patients and so were various known targets of the TGFβ signaling pathway including Collagens, Matrix metallopeptidase 2 and Fibronectin. For the over-expressed proteins quantitative RT-PCR analysis showed increased transcript levels, suggesting increased synthesis and this was further confirmed at the tissue level. Additional immunohistochemical and western blot analyses showed activation and nuclear localization of the classical TGFβ effector phospho-Smad3 in both ERS gingival tissue and ERS GFs. Exposure of the mutant cells to TGFB1 further upregulated the expression of TGFβ targets suggesting that this pathway could be a central player in the pathogenesis of the ERS gingival fibromatosis. In conclusion our data strongly suggest that TGFβ -induced modifications of the extracellular matrix contribute to the pathogenesis of ERS. To our knowledge this is the first proteomic-based analysis of FAM20A-associated modifications.

Beyond oral hygiene, are capacity-altering, biologically based interventions within the moral domain of dentistry?

Oral diseases such as dental caries (DC) and periodontitis are widely prevalent, and existing approaches to managing these conditions have only a limited effect. Accordingly, there is growing interest in the development of novel biological interventions (including, among others, CRISPR-Cas9) that might, in the future, be used to prevent the development of or cure these conditions. However, in addition to familiar concerns about using biological interventions in children who cannot provide valid consent, it is not clear whether the provision of these interventions would fall within the proper domain of dentistry. In this opinion paper, we defend the view that the provision of reasonably safe and effective novel biological interventions aimed at preventing DC and periodontitis should be understood to fall within the proper domain of dentistry. To do so, we first argue that their use would be consistent with existing practice in dentistry. We then argue that: i) they may substantially increase the recipient's wellbeing and future autonomy; and ii) that their use could constitute a form of indirect preventative medicine by addressing a threat to systemic health.

Hereditary Gingival Fibromatosis: A Report of a Rare Case in Siblings and Its Management Using Diode Laser

Hereditary gingival fibromatosis (HGF) is a proliferative fibrous lesion causing severe gingival enlargement, affecting the esthetics, as well as posing various periodontal problems. This case report addresses the diagnosis and treatment of one such rare case of HGF where the patient presented with generalized diffuse gingival enlargement involving the maxillary and mandibular arches extending on the buccal and lingual/palatal surfaces and covering the incisal/occlusal third of the tooth, resulting in altered esthetics, difficulty in speech, and mastication. Gingivectomy was carried out in all the four quadrants using diode laser. The healing was uneventful; the patient was satisfied with her esthetics and was able to resume her oral hygiene practices. Even though recurrence cannot be predicted, the risk of recurrence can be outweighed with the psychological and functional benefits. Long-term follow-up will be required to evaluate the predictability of the different surgical techniques.

Novel REST Truncation Mutations Causing Hereditary Gingival Fibromatosis

Hereditary gingival fibromatosis (HGF) is a rare genetic disorder featured by nonsyndromic pathological overgrowth of gingiva. The excessive gingival tissues can cause dental, masticatory, and phonetic problems, which impose severe functional and esthetic burdens on affected individuals. Due to its high recurrent rate, patients with HGF have to undergo repeated surgical procedures of gingival resection, from childhood to adulthood, which significantly compromises their quality of life. Unraveling the genetic etiology and molecular pathogenesis of HGF not only gains insight into gingival physiology and homeostasis but also opens avenues for developing potential therapeutic strategies for this disorder. Recently, mutations in REST (OMIM *600571), encoding a transcription repressor, were reported to cause HGF (GINGF5; OMIM #617626) in 3 Turkish families. However, the functions of REST in gingival homeostasis and pathogenesis of REST-associated HGF remain largely unknown. In this study, we characterized 2 HGF families and identified 2 novel REST mutations, c.2449C>T (p.Arg817*) and c.2771_2793dup (p.Glu932Lysfs*3). All 5 mutations reported to date are nonsenses or frameshifts in the last exon of REST and would presumably truncate the protein. In vitro reporter gene assays demonstrated a partial or complete loss of repressor activity for these truncated RESTs. When coexpressed with the full-length protein, the truncated RESTs impaired the repressive ability of wild-type REST, suggesting a dominant negative effect. Immunofluorescent studies showed nuclear localization of overexpressed wild-type and truncated RESTs in vitro, indicating preservation of the nuclear localization signal in shortened proteins. Immunohistochemistry demonstrated a comparable pattern of ubiquitous REST expression in both epithelium and lamina propria of normal and HGF gingival tissues despite a reduced reactivity in HGF gingiva. Results of this study confirm the pathogenicity of REST truncation mutations occurring in the last exon causing HGF and suggest the pathosis is caused by an antimorphic (dominant negative) disease mechanism.

Activated KCNQ1 channel promotes fibrogenic response in hereditary gingival fibromatosis via clustering and activation of Ras

BACKGROUND AND OBJECTIVE

Activated potassium channels were found to be strongly correlated with gingival overgrowth (GO) phenotype as we reviewed syndromic hereditary gingival fibromatosis (HGF). Nevertheless, the functional roles of potassium channels in gingival fibrosis or gingival overgrowth remained uncovered. The aim of the present study was to explore the pathogenic role of aberrantly activated potassium channel in Hereditary Gingival Fibromatosis (HGF).

METHODS

Gingival tissues were collected from 9 HGF patients and 15 normal controls. Expression of KCNQ1 was detected by immunohistochemistry. Gingival fibroblasts were isolated, and outward K⁺ currents were detected by whole-cell patch-clamp analysis, transmembrane potential was determined by flow cytometry. Normal human gingival fibroblasts (NHGFs) were transfected with KCNQ1 adenovirus or treated with KCNQ1 selective agonist ML277 and antagonist chromanol 293B. Accumulation of Extracellular Matrix (ECM) was measured by Western blotting and Sircol Soluble Collagen Assay. Content of secreted TGF-β1 was measured by ELISA. Active RAS pull-down assay and cell immunofluorescence were utilized to verify RAS activation.

RESULTS

KCNQ1 was upregulated in gingival tissues derived from HGF patients and HGF gingival fibroblasts presented increased outward K⁺ currents than NHGFs. Overexpression of KCNQ1, or KCNQ1 agonist ML277, promoted fibrotic responses of NHGFs. TGF-β1 and KCNQ1 channels formed a positive feed-back loop. ML277 generated lateral clustering and activation of Ras on plasma membrane, followed by augmented MAPK/AP-1 signaling pathway output. JNK or ERK1/2 inhibitors suppressed ML277-induced AP-1 and ECM upregulation.

CONCLUSION

Activation of KCNQ1 potassium channel promoted fibrogenic responses in NHGFs via Ras/MAPK/AP-1 signaling.

Hereditary gingival fibromatosis associated with the missense mutation of the KCNK4 gene

Hereditary gingival fibromatosis (HGF) is a rare oral condition that may appear as an isolated entity or as part of a genetic disease or syndrome. Molecular and biochemical mechanisms that trigger this pathologic process are not completely understood. In this article, we present a rare case of hereditary gingival fibromatosis in conjunction with a syndromic phenotype, associated with a rare missense mutation of the KCNK4 gene. This mutation induces a change in the structure of the TRAAK channel belonging to the 2-pore potassium channels. The gain of function promoted by the mutation could represent the pathogenetic basis of gingival fibromatosis.

Drug-Induced Gingival Overgrowth: The Effect of Cyclosporin A and Mycophenolate Mophetil on Human Gingival Fibroblasts

Drug-induced gingival overgrowth may occur after a chronic administration of three classes of systemic drugs: Anticonvulsants, immunosuppressants, and calcium channel blockers. This study aimed to investigate how cyclosporin A and mycophenolate mophetil (immunosuppressive drugs) could interfere with human gingival fibroblasts functions, leading to gingival enlargement. Human gingival fibroblasts derived from the tissue of a 60-year-old female were cultured in a DMEME medium. A stock solution with 1 mg/mL of mycophenolate and 1 mg/mL of cyclosporine were prepared and dissolved in a DMEM medium to prepare a serial dilution at the concentrations of 5000, 2000, 1000, 500, and 100 ng/mL, for both treatments. Cell viability was measured using the PrestoBlue™ Reagent Protocol. Quantitative real-time RT-PCR was performed in order to analyze the expression of 57 genes coding for gingival fibroblasts "Extracellular Matrix and Adhesion Molecules". Mycophenolate and cyclosporine had no effect on fibroblast cell viability at 1000 ng/mL. Both the treatments showed similar effects on the expression profiling of treated cells: Downregulation of most extracellular matrix metalloproteases genes (MMP8, MMP11, MMP15, MMP16, MMP24) was assessed, while CDH1, ITGA2, ITGA7, LAMB3, MMP12, and MMP13 were recorded to be upregulated in fibroblasts treated with immunosuppressive drugs. It has been demonstrated that gingival overgrowth can be caused by the chronic administration of cyclosporin A and mycophenolate mophetil. However, given the contrasting data of literature, further investigations are needed, making clear the possible effects of immunosuppressive drugs on fibroblasts.

Biallelic loss-of-function variants in TBC1D2B cause a neurodevelopmental disorder with seizures and gingival overgrowth

The family of Tre2-Bub2-Cdc16 (TBC)-domain containing GTPase activating proteins (RABGAPs) is not only known as key regulatorof RAB GTPase activity but also has GAP-independent functions. Rab GTPases are implicated in membrane trafficking pathways, such as vesicular trafficking. We report biallelic loss-of-function variants in TBC1D2B, encoding a member of the TBC/RABGAP family with yet unknown function, as the underlying cause of cognitive impairment, seizures, and/or gingival overgrowth in three individuals from unrelated families. TBC1D2B messenger RNA amount was drastically reduced, and the protein was absent in fibroblasts of two patients. In immunofluorescence analysis, ectopically expressed TBC1D2B colocalized with vesicles positive for RAB5, a small GTPase orchestrating early endocytic vesicle trafficking. In two independent TBC1D2B CRISPR/Cas9 knockout HeLa cell lines that serve as cellular model of TBC1D2B deficiency, epidermal growth factor internalization was significantly reduced compared with the parental HeLa cell line suggesting a role of TBC1D2B in early endocytosis. Serum deprivation of TBC1D2B-deficient HeLa cell lines caused a decrease in cell viability and an increase in apoptosis. Our data reveal that loss of TBC1D2B causes a neurodevelopmental disorder with gingival overgrowth, possibly by deficits in vesicle trafficking and/or cell survival.

Syndromes with gingival fibromatosis: A systematic review

OBJECTIVE

The aim of systematic review was to describe the phenotypes and molecular profiles of syndromes with gingival fibromatosis (GF).

METHODS

A comprehensive search of PubMed, LILACS, Livivo, Scopus, and Web of Science was conducted using key terms relevant to the research questions and supplemented by a gray literature search. The Methodological Quality and Synthesis of Case Series and Case Reports in association with the Case Series and Prevalence Studies from the Joanna Briggs Institute critical appraisal tools were used for the risk of bias. We followed the PRISMA checklist guidelines.

RESULTS

Eighty-four studies reporting GF as an oral manifestation of a syndrome were identified in this review. Enamel renal syndrome was the most frequently reported syndrome with GF, represented by 54 individuals in 19 studies, followed by Zimmermann-Laband syndrome with 24 individuals in 15 studies and Costello syndrome, which was presented in a case series study with 41 individuals. Among reported cases, other clinical manifestations such as hypertrichosis, ectopic gingival calcification, and cherubism were described.

CONCLUSIONS

The results emphasize the need of systematic oro-dental-facial phenotyping for future descriptions as well as further molecular analysis in order to better understand the occurrence of syndromic GF.

Nonsyndromic hereditary gingival fibromatosis: Characterization of a family and review of genetic etiology

Our aim is to describe a family with a nonsyndromic form of hereditary gingival fibromatosis (HGF) and discuss genetic characteristics of this rare disease by reviewing reported cases. A mother and three descendants were diagnosed with HGF. There was marked variable expressivity: from severe generalized gingival overgrowth in a 16-year-old boy (the proband) to minimal manifestations in the mother. The proband was submitted to gingivectomy and gingivoplasty. In younger siblings, the disease remained stable for 5 years, suggesting that clinical surveillance is a good option. The diagnosis was supported by histopathological examination. Analysis of this family and literature-reported cases supports that HGF most frequently shows an autosomal dominant inheritance with high penetrance and variable expressivity. Neomutations and gonadal mosaicism do not seem to be a rare event. Although five loci have been mapped by linkage analysis, only two genes, SOS1 and REST, were identified in four families.

Unusual clinical and histologic findings in a child with mixed dentition with hereditary gingival fibromatosis: a case report

Hereditary gingival fibromatosis (HGF) is characterized by an accumulation of extracellular matrix resulting in a fibrotic enlargement of keratinized gingiva. The goal of this article is to describe one kindred affected with HGF and discuss the diagnosis, treatment, recurrence risk and histopathology features of the proband with mixed dentition. An 8-year-old boy reported with a chief complaint of gingival enlargement. A series of examinations were performed to make a diagnosis and family histories of the patient were recorded. Surgical therapy included gingivectomy and gingivoplasty technique were performed for the proband to remove excess gingiva. Collagen bundles in the permanent incisors area were prevalently significantly bulkier than that of the deciduous teeth area and the arrangement was much more regular. Microscopic evaluation revealed that epithelial hyperplasia was severe in tissue with intense inflammation, whereas tissue with mild inflammation showed only long and deep epithelial papillae. The patient was placed on a 3-month recall schedule and didn't demonstrate any recurrence of gingival overgrowth over a 1-year follow-up period. The study revealed that the eruption of permanent teeth played an important role in accelerating gingival hyperplasia. For the first time, it was confirmed from histological perspective that inflammation in gingival tissue was crucial to the gingival overgrowth of HGF.

Antifibrotic Potential of MiR-335-3p in Hereditary Gingival Fibromatosis

Hereditary gingival fibromatosis (HGF) is a highly genetically heterogeneous disease, and current therapeutic method is limited to surgical resection with a high recurrence rate. MicroRNAs (miRNAs) are able to fine-tune large-scale target genes. Here we established a simple but effective computational strategy based on available miRNA target prediction algorithms to pinpoint the most potent miRNA that could negatively regulate a group of functional genes. Based on this rationale, miR-335-3p was top ranked by putatively targeting 85 verified profibrotic genes and 79 upregulated genes in HGF patients. Experimentally, downregulation of miR-355-3p was demonstrated in HGF-derived gingival fibroblasts as well as in transforming growth factor β–stimulated normal human gingival fibroblasts (NHGFs) compared to normal control. Ectopic miR-335-3p attenuated, whereas knockdown of miR-335-3p promoted, the fibrogenic activity of human gingival fibroblasts. Mechanically, miR-335-3p directly targeted SOS1, SMAD2/3, and CTNNB1 by canonical and noncanonical base paring. In particular, different portfolios of fibrotic markers were suppressed by silencing SOS1, SMAD2/3, or CTNNB1, respectively. Thus, our study first proposes a novel miRNA screening approach targeting a functionally related gene set and identifies miR-335-3p as a novel target for HGF treatment. Mechanically, miR-335-3p suppresses the fibrogenic activity of human gingival fibroblasts by repressing multiple core molecules in profibrotic networks. Our strategy provides a new paradigm in the treatment for HGF as well as other diseases.

Fibroblasts Collagen Production and Histological Alterations in Hereditary Gingival Fibromatosis

Hereditary gingival fibromatosis is a disorder for which the etiology remains unknown. We aimed to evaluate the fibroblasts and histological alterations to give new clues. A father and a daughter of a family showing gingival hereditary fibromatosis were treated, and gingival biopsies were obtained. A histological study revealed dense fibrous tissue, basal lamina disruption, and epithelial cell migration into the connective tissue. Fibroblasts were cultured from the father and daughter and compared with those from a healthy control patient. The results of the biochemical analysis showed increased collagen synthesis, reduced antioxidant CoQ₁₀ content, and high levels of lipid peroxidation. Additionally, fibroblasts culture incubation with the oxidant H₂O₂ increased collagen levels that have been reduced by the addition of the antioxidant CoQ₁₀. We conclude that some fibroblasts metabolic alterations play a significant role in initiating and maintaining persistent fibrotic tissue. Oxidative stress influences the fibroblasts collagen production and could play a particular role in the pathogenesis of hereditary gingival fibromatosis.

Oral Health Status of Kidney Transplant Patients

Drug-induced immunosuppression can predispose kidney transplant patients to different complications including chronic infections and oral lesions. We surveyed oral hygiene habits and conducted detailed periodontal examinations for status assessment. Appropriate oral hygiene and regular professional control can reduce number and severity of complications, which might be preventive for transplant rejection.

Rare Diseases with Periodontal Manifestations

Background: The object of this paper was to provide an overview of rare diseases (RDs) with periodontal manifestations and allocate them to relevant categories. Methods: In ROMSE, a database for “Rare Diseases with Orofacial Involvement”, all 541 entities were analyzed with respect to manifestations of periodontal relevance. Inclusion criteria were periodontally relevant changes to the oral cavity, in accordance with the 2018 version of the Classification of Periodontal and Peri-Implant Diseases and Conditions. Rare diseases were recorded, using the methodology described, and subsequently compared with the Orphanet Classification of Rare Diseases. Results: A total of 76 RDs with periodontal involvement were recorded and allocated in accordance with the Classification of Periodontal and Peri-Implant Diseases and Conditions. Of the 541 RDs analyzed as having known orofacial manifestations, almost 14 percent indicated a periodontally compromised dentition. Conclusions: Around 14 percent of RDs with an orofacial involvement showed periodontally relevant manifestations, which present not only as a result of gingivitis and periodontitis, but also gingival hyperplasia in connection with an underlying disease. Thus, dentists play an important role in therapy and early diagnoses of underlying diseases based on periodontally relevant manifestations.

Lumps and Bumps of the Gingiva: A Pathological Miscellany

Lesions of the gingivae are amongst the commonest lesions seen in patients and the vast majority are reactive hyperplasias, related to a number of chronic irritant stimuli. However, there are a number of entities that have a predilection for the gingivae, which are much less common in other parts of the oral cavity. The purpose of this paper is to discuss the clinical and histological differential diagnoses when presented with a lump on the gingivae, including the approach to diagnosis and diagnostic pitfalls.

Fibroblasts from recurrent fibrotic overgrowths reveal high rate of proliferation in vitro - findings from the study of hereditary and idiopathic gingival fibromatosis

PURPOSE

Investigate the content of fibrotic fibrils in gingival tissue and the proliferation of fibroblasts collected from recurrent and non-recurrent hereditary gingival fibromatosis (HGF) and idiopathic gingival fibromatosis (IGF).

METHODS

Gingival biopsies were collected from HGF (n = 3) and IGF (n = 3) donors with recurrent and non-recurrent gingival overgrowths and from a control group (Ctrl, n = 3). Hematoxylin staining was performed to evaluate the histomorphology of gingival tissue. Heidenhain's AZAN trichrome staining served for visualization of fibrotic fibrils in gingiva. Quantitative analysis of the content of fibrotic fibrils in gingival tissue was performed using a polarized light microscope. Proliferation was evaluated at 24 h, 48 h, and 72 h in fibroblast cultures using a cell proliferation ELISA assay based on 5-bromo-2'-deoxyuridine (BrdU).

RESULTS

Numerous blood vessels and fibroblasts were observed in recurrent overgrowths, whereas moderate blood vessels and moderate to scanty fibroblasts were detected in non-recurrent overgrowths. Heidenhain's staining revealed numerous collagen fibers in both recurrent and non-recurrent overgrowths. Quantitative analysis in a polarizing microscope showed significant accumulation of fibrotic fibrils exclusively in the overgrowths with the recurrence. In all time-points, increased proliferation of cells from all recurrent overgrowths was observed, but not from overgrowths which do not reoccur.

CONCLUSIONS

The study revealed that recurrent gingival overgrowths consist of highly fibrotic and dense connective tissue with numerous blood vessels and abundant fibroblasts. We also demonstrated that unlike fibroblasts derived from overgrowths, which did not present recurrence, fibroblasts derived from highly fibrotic and recurrent overgrowths maintain high rate of proliferation in vitro.

Main Oral Manifestations in Immune-Mediated and Inflammatory Rheumatic Diseases

Oral manifestations are frequent in patients with rheumatic diseases. The aim of this review is to offer readers practical advice concerning the onset, diagnosis and treatment of the main oral manifestations encountered in rheumatological and dental clinics. Signs and symptoms such as oral hyposalivation, xerostomia, temporomandibular joint disorders, periodontal disease, and dysphagia may be the first expression of a number of rheumatic diseases. Some of these manifestations are aspecific and very frequent, such as oral aphthosis, which can be the first manifestation in patients with systemic lupus erythematosus; some are potentially dangerous, such as jaw claudication during the course of giant cell arteritis; and some are very rare but peculiar, such as strawberry-like gingivitis in patients with granulomatosis with polyangiitis. Other oral manifestations are due to adverse reactions to disease-modifying anti-rheumatic drugs. Oral alterations in rheumatic diseases are frequently overlooked in clinical practice, but their prompt recognition not only allows the local lesions to be appropriately treated, but also makes it possible to identify an underlying systemic disease.

Hereditary Gingival Fibromatosis: a Case Report with Seven-Year Follow-up

Introduction

Hereditary gingival fibromatosis (HGF) is a rare disease characterized by gingival enlargement, normal color with benign and firm consistency. This growth may be exacerbated by use of drugs and plaque build-up. The treatment for this clinical condition is surgical excision of the enlarged gingival tissue or the extraction of all teeth.

Case Report

A 20-year-old Brazilian female handicapped patient with a chief complaint of exaggerated gingival enlargement who had been prescribed Carbamazepine and Gardenal was referred to our center. According to the clinical presentation and family history, the final diagnosis of gingival enlargement was HGF. Full dental treatment was performed, including basic periodontal treatment, restorations, sealants, and gingivoplasty with internal bevel. Special care was taken to ensure that there was no change in patient’s anticonvulsant medication. The patient has been monitored for seven years without signs of recurrence of gingival hyperplasia due to constant professional and home control of plaque.

TIMP-1 association with collagen type I overproduction in hereditary gingival fibromatosis

OBJECTIVES

To investigate the processes associated with the excessive production of collagen I in hereditary gingival fibromatosis (HGF).

MATERIALS AND METHODS

Three HGF subjects and five controls were enrolled in the study. Histomorphological and immunohistological analyses were performed on gingival tissues. The expression of heat-shock protein 47 (HSP47), collagen I, transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF), matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) by gingival fibroblasts isolated from HGF and controls was analysed using qRT-PCR, Western blotting and ELISA.

RESULTS

Considerable accumulation of fibrotic fibrils and increased synthesis of HSP47 were noted in HGF gingival tissues. The synthesis of collagen I, HSP47, TGF-β1, CTGF and TIMP-1 was significantly elevated in HGF gingival fibroblasts compared with controls, while the production of MMP-1 was decreased.

CONCLUSIONS

We report that fibrosis in HGF gingival tissues is associated with increased synthesis of HSP47. This finding was confirmed by an in vitro study, where excessive production of collagen I was associated with increased synthesis of HSP47, TGF-β1 and CTGF by HGF gingival fibroblasts. Moreover, the shift in the TIMP-1/MMP-1 ratio identifies increased synthesis of TIMP-1 as one of the processes associated with collagen I overproduction in HGF fibroblasts.

Change of TGF-β1 Gene Expression and TGF-β1 Protein Level in Gingival Crevicular Fluid and Identification of Plaque Bacteria in a Patient with Recurrent Localized Gingival Enlargement before and after Gingivectomy

This case report highlights the change of TGF-β1 gene expressions and TGF-β1 protein level in gingival crevicular fluid (GCF) and identification of plaque bacteria in a patient with recurrent localized gingival enlargement before and after gingivectomy treatment. A 26-year-old woman came to AG Dental Care Clinic, South Sulawesi, Indonesia, in October 2015 with a chief complaint that her gingiva often bled spontaneously and she felt pain on her gingiva and felt less comfortable and no self-confidence with her anterior and posterior gingival condition on the right maxilla region which is slightly larger than normal. She often felt that her gingiva could bleed spontaneously when she was talking or remains silent though. The patient is disturbed by the malodor she felt. At that moment, the patient sought for gingivectomy treatment. Three years afterward, the patient came back with the same complaint. Gingival crevicular fluid has been taken from the gingival sulcus before and after gingivectomy. Clinical and GCF follow-up examination was performed one week and three weeks after gingivectomy, and successful results on biological, functional, and aesthetic parameters were observed.

Gene expression profiling and bioinformatics analysis of hereditary gingival fibromatosis

Hereditary gingival fibromatosis (HGF) is a benign, non-hemorrhagic and fibrous gingival overgrowth that may cover all or part of the teeth. It typically interferes with speech, lip closure and chewing, and can also be a psychological burden that affects the self-esteem of patients. Owing to high genetic heterogeneity, genetic testing to confirm diagnosis is not justified. It is therefore important to identify key signature genes and to understand the molecular mechanisms underlying HGF. The aim of the present study was to determine HGF-related genes and to analyze these genes through bioinformatics methods. A total of 249 differentially expressed genes (DEGs), consisting of 65 upregulated and 184 downregulated genes, were identified in the GSE4250 dataset of Gene Expression Omnibus (GEO) when comparing with the gums of HGF patients with those of healthy controls using the affy and limma packages in R. Subsequently, 28 enriched gene ontology terms were obtained from the Database for Annotation, Visualization and Integrated Discovery, and a protein-protein interaction (PPI) network was constructed and analyzed using STRING and Cytoscape. There were 99 nodes and 118 edges in the PPI network of these DEGs obtained through STRING. Among these nodes, 12 core genes were identified, of which the highest degree node was the gene for POTE ankyrin domain family member I. Collectively the results indicate that bioinformatics methods may provide effective strategies for predicting HGF-related genes and for understanding the molecular mechanisms of HGF.

Autoimmune swallowing disorders

PURPOSE OF REVIEW

Dysphagia can be the presenting symptom of autoimmune disease. The otolaryngologist should be familiar with and consider these disorders when assessing the patient with swallowing difficulties.

RECENT FINDINGS

The present review gives a brief overview of Sjogren's syndrome, granulomatosis with polyangiitis, pemphigus and pemphigoid, rheumatoid arthritis, systemic lupus erythematosus, scleroderma and inflammatory myopathies, and how they affect swallowing. Diagnosis of these diseases is generally based off of clinical presentation, serology, and/or biopsy. Corticosteroids in combination with other immune modulators and symptomatic therapy are the mainstays of treatment. Treatment should be coordinated with a rheumatologist.

SUMMARY

The otolaryngologist should be able to recognize when a systemic disease may be the cause of a patient's dysphagia and guide appropriate evaluation. Furthermore, the otolaryngologist can help localize the specific nature of the swallowing problem and guide or provide treatment.

Expression of CD163 in hereditary gingival fibromatosis: A possible association with TGF-β1

BACKGROUND

Although several studies have discussed some of the molecular and cellular changes associated with hereditary gingival fibromatosis (HGF), its pathogenesis is still largely unclear. This study was directed to detect and outline the degree of relationship between the immunophenotyped macrophages (M2) expressing CD163 and TGF-β1 in patients with gingival overgrowth due to HGF.

METHODS

Biopsies from 20 patients suffering from HGF and 20 normal control subjects were harvested, histologically and immunohistochemically stained then, analyzed and statistically compared and correlated for CD163 immunoexpression and TGF-β1.

RESULTS

All HGF specimens expressed TGF-β1 by most of the connective tissue fibroblasts, with statistically high significant mean of area % (2.61 ± 0.41) compared to normal controls (0.11 ± 0.06; P = .001). All control specimens revealed negligible CD163 immunostaining of the few inflammatory cells found with a mean area of % (0.69 ± 0.12), while the specimens of HGF cases showed statistically significant higher CD163 expression (3.39 ± 0.75) at (P = .007). A statistically significant higher mean % of M2 cells expressing CD163 in relation to the total number of the inflammatory cells was revealed in HGF (34.46 ± 2.04) compared to the control group (16.36 ± 2.39; P-value ≤ .05). Moderate correlation between CD163 and TGF-β1 was detected in HGF (r = .451; P-value < .05).

CONCLUSIONS

CD163 and TGF-β1 were clearly expressed in HGF cases compared to healthy control patients, with significant correlation. In HGF, the increase in CD 163-positive cells was specific and not dependent on the chronic gingival inflammation.

REST Final-Exon-Truncating Mutations Cause Hereditary Gingival Fibromatosis

Hereditary gingival fibromatosis (HGF) is the most common genetic form of gingival fibromatosis that develops as a slowly progressive, benign, localized or generalized enlargement of keratinized gingiva. HGF is a genetically heterogeneous disorder and can be transmitted either as an autosomal-dominant or autosomal-recessive trait or appear sporadically. To date, four loci (2p22.1, 2p23.3-p22.3, 5q13-q22, and 11p15) have been mapped to autosomes and one gene (SOS1) has been associated with the HGF trait observed to segregate in a dominant inheritance pattern. Here we report 11 individuals with HGF from three unrelated families. Whole-exome sequencing (WES) revealed three different truncating mutations including two frameshifts and one nonsense variant in RE1-silencing transcription factor (REST) in the probands from all families and further genetic and genomic analyses confirmed the WES-identified findings. REST is a transcriptional repressor that is expressed throughout the body; it has different roles in different cellular contexts, such as oncogenic and tumor-suppressor functions and hematopoietic and cardiac differentiation. Here we show the consequences of germline final-exon-truncating mutations in REST for organismal development and the association with the HGF phenotype.

Analysis of mutations in the SOS-1 gene in two Polish families with hereditary gingival fibromatosis

OBJECTIVES

To establish whether two families from Malopolska and Mazovia provinces in Poland are affected by hereditary gingival fibromatosis type 1, caused by a single-cytosine insertion in exon 21 of the Son-of-Sevenless-1 gene.

MATERIAL AND METHODS

Six subjects with hereditary gingival fibromatosis and five healthy subjects were enrolled in the study. Gingival biopsies were collected during gingivectomy or tooth extraction and used for histopathological evaluation. Total RNA and genomic DNA were purified from cultured gingival fibroblasts followed by cDNA and genomic DNA sequencing and analysis.

RESULTS

Hereditary gingival fibromatosis was confirmed by periodontal examination, X-ray, and laboratory tests. Histopathological evaluation showed hyperplastic epithelium, numerous collagen bundles, and abundant-to-moderate fibroblasts in subepithelial and connective tissue. Sequencing of exons 19-22 of the Son-of-Sevenless-1 gene did not reveal a single-cytosine insertion nor other mutations.

CONCLUSIONS

Patients from two Polish families under study had not been affected by hereditary gingival fibromatosis type 1, caused by a single-cytosine insertion in exon 21 of the Son-of-Sevenless-1 gene. Further studies of the remaining regions of this gene as well as of other genes are needed to identify disease-related mutations in these patients. This will help to unravel the pathogenic mechanism of gingival overgrowth.

Gingival Fibromatosis with Significant De Novo Formation of Fibrotic Tissue and a High Rate of Recurrence

Patient: Female, 11

Final Diagnosis: Hereditary gingival fibromatosis

Symptoms: Gingival overgrowth

Medication: —

Clinical Procedure: Surgery

Specialty: Dentistry