Presumed drusen of optic nerve head in siblings with Usher syndrome.

Two siblings with Usher syndrome had optic disc mulberry tumors that were photographically documented over a 5-year period. During this period, growth of these tumors was demonstrated. These lesions were reported histologically to be drusen. The existence of presumed optic disc drusen in siblings with Usher syndrome may be related to similar pathogenetic mechanisms rather than genetic implications.