Technical Report No. 21-88
Cytogenetic study of the offspring of atomic bomb survivors, Hiroshima and Nagasaki
Awa AA, Honda T, Neriishi S, Sofuni T, Shimba H, Ohtaki K, Nakano M, Kodama Y, Itoh M, Hamilton HBSummary
This paper describes the results of a cytogenetic study on 8,322 children born to atomic bomb survivors (4,716 in Hiroshima and 3,606 in Nagasaki) and 7,976 controls (5,112 in Hiroshima and 2,864 in Nagasaki). Because no child was examined before age 12, the data may not be considered valid for the occurrence of chromosomal abnormalities that impose a high risk of early death. Thus, we will restrict our comparison to the sex-chromosome aneuploids and autosomal structural rearrangements of the balanced type, although other abnormalities encountered in this survey will be enumerated.
Among the children born to exposed parents, 19 individuals (0.23%) exhibited sex chromosome abnormalities and 23 (0.28%) exhibited autosomal structural rearrangements, whereas among children born to unexposed parents, 24 (0.30%) and 27 (0.34%), respectively, were observed to exhibit these abnormalities. Only one child with a karyotype of 47,XY,+21 was found in the Hiroshima exposed group. Thus, there was no statistically significant difference in the overall frequencies of cytogenetically abnormal cases between the exposed (0.52%) and control (0.64%) populations. In Hiroshima, frequencies of chromosome abnormalities were similar between exposed and control groups (0.64% vs 0.65%). However, the value observed in the exposed group in Nagasaki was slightly lower (0.36%)–though not statistically significant–than the value observed in the control group (0.63%). This value of the Nagasaki control group was similar to that in Hiroshima.
Family studies on probands with chromosome abnormalities revealed that the majority of cases (about 90%) with autosomal structural rearrangements of the balanced type were inherited from one or the other parent. The mutation rates for these rearrangements were similar between the exposed and control groups, being 0.98 x 10-4 per gamete per generation.
This paper describes the results of a cytogenetic study on 8,322 children born to atomic bomb survivors (4,716 in Hiroshima and 3,606 in Nagasaki) and 7,976 controls (5,112 in Hiroshima and 2,864 in Nagasaki). Because no child was examined before age 12, the data may not be considered valid for the occurrence of chromosomal abnormalities that impose a high risk of early death. Thus, we will restrict our comparison to the sex-chromosome aneuploids and autosomal structural rearrangements of the balanced type, although other abnormalities encountered in this survey will be enumerated.
Among the children born to exposed parents, 19 individuals (0.23%) exhibited sex chromosome abnormalities and 23 (0.28%) exhibited autosomal structural rearrangements, whereas among children born to unexposed parents, 24 (0.30%) and 27 (0.34%), respectively, were observed to exhibit these abnormalities. Only one child with a karyotype of 47,XY,+21 was found in the Hiroshima exposed group. Thus, there was no statistically significant difference in the overall frequencies of cytogenetically abnormal cases between the exposed (0.52%) and control (0.64%) populations. In Hiroshima, frequencies of chromosome abnormalities were similar between exposed and control groups (0.64% vs 0.65%). However, the value observed in the exposed group in Nagasaki was slightly lower (0.36%)–though not statistically significant–than the value observed in the control group (0.63%). This value of the Nagasaki control group was similar to that in Hiroshima.
Family studies on probands with chromosome abnormalities revealed that the majority of cases (about 90%) with autosomal structural rearrangements of the balanced type were inherited from one or the other parent. The mutation rates for these rearrangements were similar between the exposed and control groups, being 0.98 x 10-4 per gamete per generation.