Heterogeneity in the gingival fibromatoses

Area of Science:

• Genetics
• Oral Pathology
• Histology

Background:

• Gingival fibromatosis is a rare oral condition characterized by excessive fibrous tissue growth in the gums.
• It can be inherited (familial) or occur without a known cause (idiopathic).
• Genetic and histologic heterogeneity contribute to the varied presentations of gingival fibromatosis.

Purpose of the Study:

• To review and analyze cases of isolated familial and idiopathic gingival fibromatoses.
• To investigate the genetic heterogeneity and inheritance patterns.
• To compare the clinical features and age of onset in different forms of gingival fibromatosis.

Main Methods:

• Review of 49 cases of isolated familial and idiopathic gingival fibromatoses (12 familial, 37 idiopathic).
• Analysis of pedigrees from five families to determine inheritance patterns (autosomal dominant/recessive).
• Ultrastructural examination of lesions to identify cell types (fibroblast-like, myofibroblast-like).
• Compilation and analysis of 267 total cases from authors' data and literature (Japanese and non-Japanese).

Main Results:

• Pedigrees suggested variable penetrance and genetic heterogeneity, including autosomal dominant and recessive inheritance.
• Ultrastructural analysis revealed fibroblast-like cells as the predominant type in lesions.
• Isolated gingival fibromatosis occurred more frequently after age 12.
• Gingival fibromatosis associated with hypertrichosis, mental retardation, and/or epilepsy often occurred before age 12.

Conclusions:

• Gingival fibromatosis is a heterogeneous condition, with genetic and histologic variations.
• Inheritance patterns can be autosomal dominant or recessive.
• Age of onset differs between isolated gingival fibromatosis and forms associated with systemic disorders.