Extensive chromosome analyses have been done in F1 offspring of A-bomb survivors to determine if radiation-induced stable aberrations in parental germ cells (reciprocal translocations and inversions). No evidence was found to suggest increased F1 aberrations.

Studies compared 8,322 persons with one or both parents within 2,000 meters of the hypocenters (estimated doses of 0.01 Gy or more) and 7,976 persons with parents beyond 2,500 meters (doses less than 0.005 Gy) or not in the cities ATB. Eighteen persons in the exposed group and 25 controls carried stable aberrations (Table). Tests of parents and siblings showed that most aberrations were pre-existing and inherited from one parent. Only one from each group had a newly arisen aberration. The origin of aberrations in 16 cases could not be determined because parents had either died or did not wish to participate in the study. Dose distributions, however, were similar in tested and untested parents.

Table. Stable chromosome aberrations in children of A-bomb survivors

*Mean dose 0.60 Gy

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