Individualized digitally designed surgical template for guided soft tissue surgery in cases with severe gingival enlargement: A clinical application in hereditary gingival fibromatosis.

AIM: The purpose of this study was to present the use of computer-assisted periodontal surgery utilizing a novel surgical guide for cases with severe gingival enlargement through a clinical application in a patient with hereditary gingival fibromatosis. MATERIALS AND METHODS: The treatment plan included nonsurgical periodontal therapy, surgical periodontal treatment, and regular periodontal maintenance before the initiation of orthodontic treatment. Due to the increased soft tissue thickness, a surgical guide with a novel design was fabricated to facilitate the periodontal surgery since most of the patient's teeth were malpositioned and underexposed due to fibromatosis. For this purpose, the patient's intraoral scan was merged with a CBCT image in order to plan surgical excisions based on the anatomy of the teeth and the bone contour. RESULTS: The customized surgical guide facilitated the gingivectomy by controlling not only the shape of the initial incisions but also their orientation toward the level of the cementoenamel junction, improving the efficiency of the clinical time compared with freehand surgery and assisting in the verification of the final soft tissue shape, based on the treatment plan. CONCLUSION: Digital technology through the superimposition of multiple data sets can assist in the diagnosis and multidisciplinary management of cases with gingival fibromatosis. The proposed design of the surgical guide can facilitate soft tissue surgery based on the digital treatment plan, leading to more predictable management of the soft tissue, especially in patients with severe gingival enlargement, as in cases with hereditary gingival fibromatosis or drug-induced gingival overgrowth.

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.

Zimmermann-Laband syndrome and infantile systemic hyalinosis: an enigma with two separate terms with overlapping features: a case report.

BACKGROUND: Zimmermann-Laband Syndrome (ZLS) and infantile systemic hyalinosis (ISH) are rare genetic disorders. They are characterized by various spectrum manifestations. In spite of other case reports, this case with features of both syndromes was reported by oral medicine specialists and oral and maxillofacial surgeons. CASE PRESENTATION: In this study, we reported an 18-months old female patient with gingival overgrowth. This phenomenon completely embedded all the erupted teeth. In this case, the presence of multiple papulonodular cutaneous lesions is a newly observed aspect that has rarely been reported in the existing literature. Gingival overgrowth was excised under general anesthesia. At six months of follow-up after surgery, mastication and breathing problems were improved. Aesthetic aspects were ameliorated in terms of gingival appearance. CONCLUSIONS: To date, due to the ambiguous presentations, both syndromes remain an enigma for specialists. A timely diagnosis could be crucial for prognosis and preventing severe further surcharge. Dentists could play an important role in the diagnosis of rare disorders.

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.

New evidence of genetic heterogeneity causing hereditary gingival fibromatosis and ALK and CD36 as new candidate genes.

BACKGROUND: Hereditary gingival fibromatosis (HGF) is an uncommon genetic condition characterized by slow but progressive fibrous, non-hemorrhagic, and painless growth of the gingival tissues due to the increased deposition of collagen and other macromolecules of the extracellular matrix. HGF occurs in approximately 1:750,000 individuals and can exhibit dominant or recessive inheritance. To date, five loci (2p21-p22, 2p22.3-p23.3, 4q12, 5q13-q22, and 11p15) and three genes [REST (RE1-silencing transcription factor), SOS1 (Son-of-Sevenless-1), and ZNF862 (zinc finger protein 862 gene)] have been associated with HGF. Here, our study aimed to identify genetic variants associated with HGF by applying whole-exome sequencing (WES) and bioinformatics analyses. METHODS: Thirteen Brazilian individuals with HGF and nine relatives without HGF from four unrelated families were chosen for our investigation. Blood collected from the patients and their relatives were used for WES. Five Web-available tools, namely, CADD, PolyPhen, SIFT, Mutation Taster, and Franklin's algorithms, were used to predict protein damage. RESULTS: WES revealed pathogenic variants affecting the known HGF genes REST (c.1491_1492delAG) and SOS1 (c.3265_3266insTAAC) in two families. Additionally, potentially pathogenic variants segregating in the other two families were mapped to ALK receptor tyrosine kinase gene (ALK) (c.361C > T) and to collagen type I receptor and thrombospondin receptor gene (CD36) (c.1133G > T). CONCLUSION: Our findings reinforce the high genetic heterogeneity of HGF, identifying new variants in HGF known genes (REST and SOS1) and ALK and CD36 as new genes that cause HGF.

Pathogenic REST variant causing Jones syndrome and a review of the literature.

Jones syndrome is a rare dominantly inherited syndrome characterized by gingival fibromatosis and progressive sensorineural hearing loss becoming symptomatic in the second decade of life. Here, we report a father and his two daughters presenting with a typical Jones syndrome (OMIM %135550) phenotype. Exome sequencing identified a repressor element 1-silencing transcription factor (REST, OMIM *600571) (NM_005612.5) c.2670_2673del p.(Glu891Profs*6) heterozygous variant segregating with Jones syndrome in the family. We review the clinical data from all previously published patients with Jones syndrome and previously published patients with pathogenic REST variants associated with gingival fibromatosis or sensorineural hearing loss. This study suggests that pathogenic REST variants cause Jones syndrome.

Modified gingivoplasty for hereditary gingival fibromatosis: two case reports.

BACKGROUND: Hereditary gingival fibromatosis (HGF) is characterized by sub-epithelial fibromatosis of keratinized gingiva resulting in a fibrotic enlargement of keratinized gingiva. The treatment choice is gingivectomy, which can be performed with an internal or external bevel incision conventionally. However, both techniques can hardly resume the natural status of gingiva, and have a certain recurrence rate, especially in the cases which have limited width of attached gingiva. CASE DESCRIPTION: Two cases of HGF with the chief complaint of difficulty in mastication, pronunciation, and poor esthetics were presented. After the initial periodontal therapy, a novel gingivoplasty modified with a crevicular incision was applied. A full thickness flap above the mucogingival junction and a split flap below the junction were raised. Then, fibrotic connective tissue was completely eliminated and keratinized gingival epithelium was preserved. The fibrotic alveolar bone was shaped by handpiece and bur. Finally, the flap was apically repositioned and sutured. Twelve months after surgery, the gingiva recovered with normal color, contour and consistency. CONCLUSIONS: Compared to traditional gingivectomy, modified gingivoplasty which focuses on eliminating pathological fibrotic connective tissue can completely resume the natural appearance of gingiva and demonstrate no tendency of recurrence.

A 15-year Follow-Up of a Gingivectomy Procedure for Idiopathic Gingival Fibromatosis: A Case Report and Literature Review.

Few long-term reports exist concerning the treatment of idiopathic gingival fibromatosis, which is a rare autosomal dominant genetic disorder associated with non-inflammatory, benign, and chronic fibrous gingival proliferation and which causes serious esthetic problems. The aim of this study was to report a case of idiopathic gingival fibromatosis treated with a gingivectomy using an inverse bevel flap method and comprehensively followed up for 15 years. A female patient visited a pediatric dentist at 7 years of age; however, a gingivectomy was not performed until the age of 20 years because of an uncertain prognosis. Now, more than 15 years after the gingivectomy, there has been no significant recurrence and the disease is well managed. Treatment by gingivectomy with an inverse bevel flap approach may provide long-term prevention of recurrence of gingival fibromatosis into adulthood. The aim of this study was to obtain new findings on the pathogenesis and prognosis of this rare disease and to review the case reports previously published.

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.

Zimmermann-Laband syndrome in monozygotic twins with a mild neurobehavioral phenotype lacking gingival overgrowth-A case report of a novel KCNN3 gene variant.

Zimmermann-Laband syndrome is a rare, heterogeneous disorder characterized by gingival hypertrophy or fibromatosis, aplastic/hypoplastic nails, hypoplasia of the distal phalanges, hypertrichosis, various degrees of intellectual disability, and distinctive facial features. Three genes are considered causative for ZLS: KCNH1, KCNN3, and ATP6V1B2. We report on a pair of female concordant monozygotic twins, both carrying a novel pathogenic variant in the KCNN3 gene, identified using exome sequencing. Only six ZLS patients with the KCNN3 pathogenic variant have been reported so far. The twins show facial dysmorphism, hypoplastic distal phalanges, aplasia or hypoplasia of nails, and hypertrichosis. During infancy, they showed mild developmental delays, mainly speech. They successfully completed secondary school education and are socio-economically independent. Gingival overgrowth is absent in both individuals. Our patients exhibited an unusually mild phenotype compared to published cases, which is an important diagnostic finding for proper genetic counseling for Zimmermann-Laband syndrome patients and their families.

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.

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 TGFß 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 TGFß 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 TGFß effector phospho-Smad3 in both ERS gingival tissue and ERS GFs. Exposure of the mutant cells to TGFB1 further upregulated the expression of TGFß 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 TGFß -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.

Hyaline fibromatosis syndrome: a case presenting with gingival enlargement as the only clinical manifestation and a report of two new mutations in the ANTXR2 gene.

BACKGROUND: Hyaline fibromatosis syndrome (HFS) is a rare autosomal recessive disorder caused by mutations in the gene for anthrax toxin receptor-2 (ANTXR2). The clinical features of HFS include skin thickening with nodules, papules and plaques, gingival enlargement, joint stiffness and contractures, and systemic manifestations. Notably, in all patients with HFS reported in the literature, gingival enlargement has never occurred alone. CASE PRESENTATION: A case of a child with gingival enlargement as the only clinical manifestation, who was later diagnosed with HFS, is described. In this case, the absence of skin and joint lesions and other characteristic clinical presentations gave rise to a diagnostic problem. This uncommon condition was clinically indistinguishable from other diseases or conditions that presented with diffuse gingival enlargement. A definitive diagnosis of HFS was reached through genetic analysis. Trio whole exome sequencing revealed compound heterozygous mutations of ANTXR2 in this patient and two new mutations were reported. CONCLUSIONS: The findings of this case serve as an important reminder to clinicians. When dental practitioners encounter gingival manifestations of HFS without accompanied skin or joint involvement, there is a need to pay attention to the differential diagnosis and increase awareness of HFS.

Seven-year follow-up of a patient with hereditary gingival fibromatosis treated with a multidisciplinary approach: case report.

BACKGROUND: Hereditary gingival fibromatosis (HGF) is rare in clinical practice, and the long-term results of the combined orthodontic-periodontal treatment of HGF are rarely reported. CASE PRESENTATION: This study reports for the first time the results of seven years of follow-up in a seven-year-old girl with HGF. The diagnosis was confirmed by clinical signs, family history and histopathological examination. First, periodontal scaling and oral hygiene reinforcement were performed regularly in the mixed dentition stage. Next, gingivoplasty was performed on the permanent dentition. Two months after the surgery, treatment with fixed orthodontic appliances was conducted. The teeth were polished on a monthly basis, and oral hygiene was reinforced to control gingival enlargement. Gingival hypertrophy recurred slightly, and gingivectomies were performed in the months following the start of orthodontic treatment. Follow-up was performed for 24 months with orthodontic retention, and gingival enlargement remained stable after the combined treatment. CONCLUSIONS: The risk of gingival hyperplasia recurrence during and after orthodontic treatment is high, but satisfying long-term outcomes can be achieved with gingivectomy, malocclusion correction, and regular follow-up maintenance.

Hereditary gingival fibromatosis: a case report / Fibromatosis gingival hereditaria: informe de caso

Introduction: Hereditary gingival fibromatosis is a rare disorder with a genetic component that may appear during tooth replacement. This condition can cause functional and aesthetic problems such as malocclusions, diastemas, pain when chewing, dental caries, periodontal disease, delayed eruption, among others. Objective: To report the multidisciplinary treatment provided to a patient with hereditary gingival fibromatosis. Case Report: This report describes the treatment carried out in a thirteen-year-old male patient presenting generalized increase in gingival volume associated with functional and aesthetic compromise and delayed eruption of permanent teeth. After diagnosis, a multidisciplinary intervention was proposed, involving periodontal and pediatric dentistry procedures, which improved the quality of life of the patient both functionally and aesthetically. Conclusion: Hereditary gingival fibromatosis not only affects the dental eruption process, but also causes aesthetic and emotional alterations in the patient. The periodontal procedures significantly improved the appearance, function, and the psychological state of the patient.

Introducción: La fibromatosis gingival hereditaria es una altera-ción poco común, asociada a un componente genético que en ocasiones se hace evidente en el recambio dentario. Este padecimiento puede generar problemas funcionales y estéticos como maloclusiones, diastemas, dolor al masticar, caries, enfermedad periodontal, erupción tardía, entre otros. Objetivo: Reportar el caso clínico con manejo interdisciplinario en un paciente con fibromatosis gingival hereditaria. Reporte de Caso: Se expone el tratamiento realizado en un paciente de trece años, sexo masculino, con aumento de volumen gingival generalizado con compromiso funcional y estético, conjugado con retraso en la erupción de dientes permanentes. Tras diagnóstico se plantea la intervención multidisciplinaria, integrando áreas como periodoncia y odontopediatría; los procedimientos ejecutados permitieron mejorar la calidad de vida desde el punto de vista funcional y estético. Conclusión: La fibromatosis gingival hereditaria no solo desencadena alteración en proceso eruptivo dental, sino también alteraciones estéticas y emocionales en el paciente que la padece. Los procedimientos perio-dontales realizados permitieron de forma categórica la mejora de la estética, función y estado psicológico del paciente.

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.

Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K+ channelopathies.

Decreased or increased activity of potassium channels caused by loss-of-function and gain-of-function (GOF) variants in the corresponding genes, respectively, underlies a broad spectrum of human disorders affecting the central nervous system, heart, kidney, and other organs. While the association of epilepsy and intellectual disability (ID) with variants affecting function in genes encoding potassium channels is well known, GOF missense variants in K+ channel encoding genes in individuals with syndromic developmental disorders have only recently been recognized. These syndromic phenotypes include Zimmermann-Laband and Temple-Baraitser syndromes, caused by dominant variants in KCNH1, FHEIG syndrome due to dominant variants in KCNK4, and the clinical picture associated with dominant variants in KCNN3. Here we review the presentation of these individuals, including five newly reported with variants in KCNH1 and three additional individuals with KCNN3 variants, all variants likely affecting function. There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis. We suggest to combine the phenotypes and define a new subgroup of potassium channelopathies caused by increased K+ conductance, referred to as syndromic neurodevelopmental K+ channelopathies due to dominant variants in KCNH1, KCNK4, or KCNN3.

Association of mutation in PTPN14 gene and gingival fibromatosis with distinctive facies: a novel finding in whole exome sequencing.

Gingival fibromatosis with distinctive facies presents a rare clinical picture. It is characterized by gingival fibromatosis in conjunction with some craniofacial dysmorphic features such as relative macrocephaly, bushy eyebrows, synophrys, hypertelorism, downslanting palpebral fissures, flattened nasal bridge, hypoplastic nares, cupid-bow mouth and a high palate. Autosomal recessive inheritance has been suggested. However, to date, no causative gene has been reported. Herein, we report a case presenting with the typical findings of this rare genetic syndrome. A homozygous c.1855C>T (p.Gln619Ter) mutation in the PTPN14 gene was identified.