Clinical and genetic problems in familial in-intestinal polyposis.

The history of a family suffering from familial intestinal polyposis is presented, showing how a delayed onset of symptoms together with a lack of knowledge of affected relatives may obscure the familial nature of the disease. The necessity of examining all accessible relatives, irrespective of their advancing years, is stressed. Further, it is shown that in the absence of any familial incidence the proper diagnosis of an isolated case of polyposis is that the disease is the result of a fresh mutation.The possibility of a non-familial form of this disease cannot be proved at present and will require a special genetic investigation. It is emphasized that the diagnosis of non-familial polyposis should not be made, as this will lead to a relaxation of the vigil that should be kept on the descendants of all patients with polyposis.