Hereditary gingival fibromatosis is frequently an isolated condition of little consequence apart from a cosmetic problem and occasional associations with hypertrichosis and/or epilepsy. There are, however, several uncommon or rare eponymous syndromes described in which gingival fibromatosis can be a feature: these include the Zimmermann-Laband, Murray-Puretic-Drescher, Rutherfurd, Cowden and Cross syndromes. This paper describes two siblings with features of the rare Zimmermann-Laband syndrome and discusses the major aspects of this and other eponymous syndromes that may be associated with hereditary gingival fibromatosis.