Ultrastructural aspects of connective tissue in hereditary gingival fibromatosis

Objective. The purpose of this study was to analyze the ultrastructure of g ingival connective tissue from patients in one family affected by hereditar y gingival fibromatosis (HGF). Study design. Electron microscopic examination was performed with gingival tissue from 10 patients from a Brazilian family with 132 members. Fifty of 96 persons at risk for this disorder were affected, which is consistent wit h an autosomal dominant pattern of inheritance. Results. The extracellular matrix showed flocculent material and collagen f ibrils with structural abnormalities and variation in diameter. Increased n umbers of oxytalan fibers were identified; however, elastic fibers were rar e in the analyzed areas. Conclusions. The structural alterations found in HGF appear similar to thos e described in certain other heritable collagen disorders, suggesting that HGF should be included in the group of hereditary diseases in which connect ive tissue alterations have a distinct pattern, in contrast to reactive fib rotic gingival enlargements with no genetic component.