A study of the ultrastructure and gene location of hereditary gingival fibromatosis.

OBJECTIVE: To ascertain histology changes of hereditary gingival fibromatosis (HGF) and the location of HGF gene. METHODS: A pedigree analyses of HGF; and the ultrastructure of gingival overgrowth tissue was observed with electron microscopy. The overgrowth of the HGF gene was defined with microsatellite markers. RESULTS: The connective tissue of HGF consisted of coarse collagen bundles and several kinds of cells arranged abnormally, such as: epithelial cells, smooth muscle cells and so on; the HGF locus had been mapped to chromosome 5q13-q22. CONCLUSIONS: The gingival pathologic changes resemble "hamartoma"; the findings has implications for identification of the underlying genetic basis of HGF.