Genetics of Retinoblastoma

IT HAS been recognized for many years that the distribution of the malignant ocular neoplasm most commonly termed retinoblastoma is not at random in human populations. Although the great majority of persons with this disease are not known to have any relative similarly affected, there has been observed, considering the rarity of the neoplasm, a disproportionate frequency of both "horizontal" and "vertical" constellations. By the term "horizontal" we refer to the occurrence of two or more affected children in a single sibship, both parents being normal in this respect; by the term "vertical" we refer to an affected parent with one or more affected children. The extensive literature documenting this point has been adequately reviewed elsewhere.¹The currently accepted genetic explanation of these findings is largely derived from the papers of Weller,1bGriffith and Sorsby,1cFranceschetti and Bischler,1eand Falls.²In brief, it is postulated