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

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.

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.

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.