Genetic heterogeneity of gingival fibromatosis on chromosome 2p.
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Gingival fibromatosis (GF) occurs in several genetic forms as a simple Mendelian trait, in malformation syndromes, and in some chromosomal disorders. Specific genes responsible for GF have not been identified. An autosomal dominant form of hereditary gingival fibromatosis (HGF, MIM 135300) was recently mapped to chromosome 2p21 in a large Brazilian family and there was an earlier report of GF in a boy with a cytogenetic duplication involving 2p13-->p21. We thus hypothesised that a common gene locus may be responsible for GF in both the Brazilian family and the boy with the chromosome 2p duplication. We performed additional genetic linkage studies on the Brazilian family and molecular cytogenetic studies on the patient with the cytogenetic duplication to correlate more precisely the genetic interval of the HGF phenotype with the duplicated 2p interval. Additional linkage analysis of new family members resulted in refinement of the candidate region for HGF to an 8 Mb region. Molecular cytogenetic analysis of the 2p13-->p21 duplication associated with GF showed that the duplicated region was proximal to the candidate interval for HGF. Thus, our results support the presence of two different gene loci on chromosome 2p that are involved in GF. (+info)
A mutation in the SOS1 gene causes hereditary gingival fibromatosis type 1.
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Hereditary gingival fibromatosis (HGF) is a rare, autosomal dominant form of gingival overgrowth. Affected individuals have a benign, slowly progressive, nonhemorrhagic, fibrous enlargement of the oral masticatory mucosa. Genetic loci for autosomal dominant forms of HGF have been localized to chromosome 2p21-p22 (HGF1) and chromosome 5q13-q22 (HGF2). To identify the gene responsible for HGF1, we extended genetic linkage studies to refine the chromosome 2p21-p22 candidate interval to approximately 2.3 Mb. Development of an integrated physical and genetic map of the interval identified 16 genes. Sequencing of these genes, in affected and unaffected HGF1 family members, identified a mutation in the Son of sevenless-1 (SOS1) gene in affected individuals. In this report, we describe the genomic structure of the SOS1 gene and present evidence that insertion of a cytosine between nucleotides 126,142 and 126,143 in codon 1083 of the SOS1 gene is responsible for HGF1. This insertion mutation, which segregates in a dominant manner over four generations, introduces a frameshift and creates a premature stop codon, abolishing four functionally important proline-rich SH3 binding domains normally present in the carboxyl-terminal region of the SOS1 protein. The resultant protein chimera contains the wild-type SOS1 protein for the N-terminal amino acids 1-1083 fused to a novel 22-amino acid carboxyl terminus. Similar SOS1 deletion constructs are functional in animal models, and a transgenic mouse construct with a comparable SOS1 chimera produces a phenotype with skin hypertrophy. Clarification of the functional role of this SOS1 mutant has implications for understanding other forms of gingival fibromatosis and corrective gingival-tissue management. (+info)
Treatment and long-term follow-up of a patient with hereditary gingival fibromatosis: a case report.
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This report addresses the complex nature of oral diagnosis, treatment and long-term case management in the hereditary form of recurrent gingival fibromatosis. Case management is discussed in relation to a 13-year-old girl who presented with recurrent, progressive gingival enlargement requiring consecutive periodontal and orthodontic treatment. The initial course of treatment included 4-quadrant gingivectomy with reverse bevel incisions, followed by orthodontics. Microscopic examination of the gingivectomy specimens supported the clinical diagnosis. Three years later, recurrence of the condition was observed in all quadrants. To facilitate orthodontic tooth movement and to achieve optimal esthetics, another full-mouth gingivectomy was performed. There was no recurrence of the condition a year later. It is recommended that patients with this condition be monitored closely after gingivectomy, so that the treatment requirements of localized areas can be addressed as needed. (+info)
Idiopathic gingival hyperplasia and orthodontic treatment: a case report.
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There are many reasons for gingival hyperplasia. Mostly, proper oral hygiene is sufficient to achieve normal healthy gingiva. In some situations, however, gingival hyperplasia is drug-induced or can be a manifestation of a genetic disorder. In the latter, it may exist as an isolated abnormality or as part of a syndrome. If orthodontic treatment is needed in patients with gingival hyperplasia, both orthodontic and periodontal aspects need to be considered. Extreme hereditary gingival fibromatosis was periodontally treated, by removal of all gingival excess using flaps and gingivectomies. After a follow-up period, the orthodontic treatment started with fixed appliances. Monthly periodontal check-ups (scaling and polishing) were scheduled to control the gingival inflammation. After the orthodontic treatment, permanent retention was applied, once more followed by a complete gingivectomy in both maxilla and mandible. One of the most important keys to successful treatment of hyperplasia patients is the cooperation between the periodontist and the orthodontist. (+info)
Removal of hyperplastic lesions of the oral cavity. A retrospective study of 128 cases.
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AIMS: Based on our accumulated experience, the present study evaluates and discusses the indications, advantages and inconveniences of oral cavity epulis resection using the carbon dioxide laser (CO2) versus the Erbium:YAG laser (Er:YAG), diode laser and surgical scalpel. MATERIAL AND METHODS: A retrospective study has been made of 120 patients involving the removal of 128 epulis lesions with the CO2 laser, Er:YAG laser, diode laser and surgical scalpel. Postoperative controls were carried out after 7, 15 and 30 days to evaluate healing and wound evolution, and after 3, 6 and 12 months to assess possible relapse. RESULTS: Two groups were defined, based on the clinical and etiopathogenic characteristics of the excised lesions: gingival hyperplastic lesions (77 cases) and fibromatous hyperplasia (51 cases). The lower jaw was the most frequent location of gingival hyperplasia (51.9%). Fibrous hyperplasia was the most common histological diagnosis (49 cases; 63.6%). Percentage relapse following removal was 9.1%, of which 5 cases corresponded to fibrous hyperplasia. Only one malignancy was identified, corresponding to infiltrating squamous cell carcinoma. On the other hand, of the 51 treated cases of fibromatous hyperplasia, 58.8% were located in the upper jaw. These were histologically confirmed to be fibrous hyperplasia, with relapse in 19.6% of the cases. CONCLUSIONS: Although the different surgical techniques used for removal of epulis of the oral cavity are appropriate, we consider the CO2 laser to be the treatment of choice, since it offers a number of both intra- and postoperative advantages. On the other hand, all oral lesions require histological study to establish a firm diagnosis. (+info)
CCN2, connective tissue growth factor, stimulates collagen deposition by gingival fibroblasts via module 3 and alpha6- and beta1 integrins.
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CCN2, (connective tissue growth factor, CTGF) is a matricellular factor associated with fibrosis that plays an important role in the production and maintenance of fibrotic lesions. Increased collagen deposition and accumulation is a common feature of fibrotic tissues. The mechanisms by which CCN2/CTGF contributes to fibrosis are not well understood. Previous studies suggest that CTGF exerts some of its biological effects at least in part by integrin binding, though this mechanism has not been previously shown to contribute to fibrosis. Utilizing full length CCN2/CTGF, CCN2/CTGF fragments, and integrin neutralizing antibodies, we provide evidence that the effects of CCN2/CTGF to stimulate extracellular matrix deposition by gingival fibroblasts are mediated by the C-terminal half of CCN2/CTGF, and by alpha6 and beta1 integrins. In addition, a synthetic peptide corresponding to a region of CCN2/CTGF domain 3 that binds alpha6beta1 inhibits the collagen-deposition assay. These studies employed a new and relatively rapid assay for CCN2/CTGF-stimulated collagen deposition based on Sirius Red staining of cell layers. Data obtained support a pathway in which CCN2/CTGF could bind to alpha6beta1 integrin and stimulate collagen deposition. These findings provide new experimental methodologies applicable to uncovering the mechanism and signal transduction pathways of CCN2/CTGF-mediated collagen deposition, and may provide insights into potential therapeutic strategies to treat gingival fibrosis and other fibrotic conditions. (+info)
Epithelial and connective tissue cell CTGF/CCN2 expression in gingival fibrosis.
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Gingival overgrowth is a side effect of certain medications and occurs in non-drug-induced forms either as inherited (human gingival fibromatosis) or idiopathic gingival overgrowth. The most fibrotic drug-induced lesions develop in response to therapy with phenytoin; the least fibrotic lesions are caused by cyclosporin A; and intermediate fibrosis occurs in nifedipine-induced gingival overgrowth. Connective tissue growth factor (CTGF/CCN2) expression is positively related to the degree of fibrosis in these tissues. The present study has investigated the hypothesis that CTGF/CCN2 is expressed in human gingival fibromatosis tissues and contributes to this form of non-drug-induced gingival overgrowth. Histopathology/immunohistochemistry studies showed that human gingival fibromatosis lesions are highly fibrotic, similar to phenytoin-induced lesions. Connective tissue CTGF/CCN2 levels were equivalent to the expression in phenytoin-induced gingival overgrowth. The additional novel observation was made that CTGF/CCN2 is highly expressed in the epithelium of fibrotic gingival tissues. This finding was confirmed by in situ hybridization. Real-time polymerase chain reaction (PCR) analyses of RNA extracted from drug-induced gingival overgrowth tissues for CTGF/CCN2 were fully consistent with these findings. Finally, normal primary gingival epithelial cell cultures were analysed for basal and transforming growth factor beta1 (TGF-beta1) or lysophosphatidic acid-stimulated CTGF/CCN2 expression at protein and RNA levels. These data indicate that fibrotic human gingival tissues express CTGF/CCN2 in both the epithelium and connective tissues; that cultured gingival epithelial cells express CTGF/CCN2; and that lysophosphatidic acid further stimulates CTGF/CCN2 expression. These findings suggest that interactions between epithelial and connective tissues could contribute to gingival fibrosis. (+info)
Characterization of fibroblasts with Son of Sevenless-1 mutation.
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Although non-syndromic hereditary gingival fibromatosis (HGF) is genetically heterogeneous, etiologic mutations have been identified only in the Son of Sevenless-1 gene (SOS1). To test evidence of increased cell proliferation, we studied histological, morphological, and proliferation characteristics in monolayer and three-dimensional cultures of fibroblasts with the SOS1 g.126,142-126,143insC mutation. Histological assessment of HGF gingiva indicated increased numbers of fibroblasts (30%) and increased collagen (10%). Cell proliferation studies demonstrated increased growth rates and 5-bromo-2-deoxyuridine incorporation for HGF fibroblasts. Flow cytometry showed greater proportions of HGF fibroblasts in the G2/M phase. Attachment of HGF fibroblasts to different extracellular matrix surfaces demonstrated increased formation of protrusions with lamellipodia. HGF fibroblasts in three-dimensional culture showed greater cell proliferation, higher cell density, and alteration of surrounding collagen matrix. These findings revealed that increased fibroblast numbers and collagen matrix changes are associated with mutation of the SOS1 gene in vitro and in vivo. (+info)