Abstract
Tetraploidy was increased in skin fibroblast cultures derived from three probands with the Gardner syndrome and nine affected members of one family as compared to that occurring in cultures from five unaffected family members as well as from six relatives by marriage and 15 normals grown in the laboratory at the same time under the same conditions. Tetraploidy was present at the first subculture (2 weeks after the initial biopsy was cultured) and for each line studied the percentage of dividing cells showing tetraploidy remained constant. Increased occurrence of tetraploidy was not observed in skin fibroblast cultures from patients with the genetic disorders familial polyposis coli, familial osteomas, and familial fibromatosis (neurofibromatosis), each of which show one of the four abnormal tissue growths observed in the Gardner syndrome. The relationship of the observed tetraploidy to the increased risk of such patients to develop abnormal growths and cancer has not been established. The increased tetraploidy should be of value in identifying the presence of the gene for the Gardner syndrome in high risk families.