Turcot's syndrome and its mode of inheritance

Two sisters with Turcot's syndrome, in which malignant cerebral neoplasms are associated with colonic polyposis, are presented. Cases reported in the literature, including some familial cases, have also been analysed. In familial cases, sex was unrelated to the occurrence of this disease and it was found only among siblings of the same parents and not in other members of the family. There was consanguinity in the parents of the patients in two out of three families. We therefore concluded that the mode of inheritance in this condition is autosomal recessive and that it is genetically distinct from the ordinary form of familial polyposis coli. Support is lent to the absence of an association between the two disorders by a difference in the number, size, and distribution of the colonic polyps found in Turcot's syndrome as compared with familial polyposis coli.