Histochemical and biochemical study of hereditary fibrous hyperplasia of the gingiva.

Four patients with hereditary hyperplasia of the gingiva were studied. Biopsy samples of gingival tissue contained subepithelial loose connective tissue with thick rounded fibroblasts or dense collagen-rich connective tissue with thin fibroblasts, which appeared to be inactive. These two types of fibroblasts differed in electron microscopy. Alcian blue-staining of intercellular material in various MgCl2 concentrations was similar in hyperplastic and control samples. Collagen from the hyperplastic gingiva appeared to be more mature than normal, based on the presence of stable, nonreducible cross lines. An investigation of growth hormone secretion and a treatment trial suggested that the growth retardation observed in earlier studies was due to normal variation in growth rates or (in one patient) to hypopituitarism associated with birth in breech presentation.