Familial leukemia and inherited chromosomal aberration.

This communication contributes a family with 12 cases of cancer and two cases of leukemia. Chromosomal analysis was performed on three occasions, 9 months apart. In unaffected first-degree relatives, we have demonstrated high frequency of tetraradial figures: in parents, 1:243 mitoses, and in all first degree relatives, 1:328 mitoses. The rate of chromosomal breakage was moderately elevated in comparison with carefully matched controls, mainly in father (6.17), mother (4.01) and one sister (4.07). G-banded and C-banded karyotypes revealed no structural chromosomal abnormality in relatives of leukemic children. This family is one of five leukemic families investigated. Analogous methods of chromosomal analysis have been employed in all, but chromatid exchange figures and elevated chromosomal breakage were detected only in the presently reported pedigree. It has been postulated that in this family there exists a possible relation between increased incidence of chromatid exchange figures and increased tendency to leukemia.