Commentary and Review Series 5-92
Report of a workshop on the application of molecular genetics to the study of mutation in the children of atomic-bomb survivors
Neel JV, Satoh C, Myers RMutat Res 291:1-20, 1993
Summary
Following are the recommendations of the workshop.
1. The workshop recognized that the traits used as indicators of genetic damage in the previous studies on the genetic effects of A-bomb radiation all ultimately trace back to variation at the DNA level, some more directly than others, and expressed the opinion that it would be useful to attempt to estimate the amount of F1 DNA that had in effect already been screened for mutational damage.
2. The workshop, in view of the recent molecular characterization of many of the genes responsible for “sentinel phenotypes” and the resulting possibility of specifying the total amount of DNA being screened by a consideration of these phenotypes, raised the possibility of further medical examinations of the F1, with particular reference to the occurrence of “sentinel phenotypes.” The sentinel phenotypes should include microdeletion syndromes and an assessment of mental retardation. Given the increased knowledge of genetic diseases, particularly polygenic/multifactor diseases, further, medical evaluations of the F1 cohort (or review of health records) should be considered.
3. The workshop agreed that it would be appropriate to initiate at this time a major pilot study employing the DNA methodologies discussed by C. Satoh, including denaturing-gradient-gel electrophoresis and Southern-blot analysis to look for insertions/deletions/rearrangements and possibly high-resolution electrophoresis for microsatellite loci. The precise efficiencies achieved with the various techniques discussed will need to be evaluated after several years of experience.
4. With respect to the choice of loci for this pilot study, basically two alternatives were recognized: to study a relatively few loci in the entire material or to study in a subsample of the material more loci (perhaps 10-15); the latter would be selected to be representative of various components of the genome. Genes mentioned in the course of the discussion include the loci encoding for the HLA, immunoglobulin, FMR-1, factors VIII and IX, globin genes, several VNTRs, and microsatellite loci. The p53 gene might be a valuable gene to study for comparing the accumulated data on the somatic-mutation analysis of this important human tumor-suppressor gene with any germinal-mutation-spectrum data. It was suggested that the appropriate selection of loci be studied in approximately 50 of the family constellations available for the exposed population and another 50 from the controls.
A minority of the panel expressed the view that it might be desirable to base the initial studies on genes sensitive to radiation mutagenesis, with the thought that if these showed no damage, the study would not be carried further. However, it was agreed that current knowledge did not permit the selection of such genes.
5. The workshop recognized the large body of data on population variation that would result from this study and the complexity of the resulting data base. It therefore recommended that work be initiated on the design of an appropriate data base, which, in view of the desirability of data exchange, should be compatible with the data bases of various national genome projects.
6. In view of the magnitude of the program, and the desirability of collaborative arrangements that would supplement the efforts of RERF staff, guidelines for such collaboration should be developed. Three initial issues with respect to the guidelines were the following: a) Because of local sensitivities in the cities of Hiroshima and Nagasaki, collaborative projects should, if possible, be carried out at RERF. To send such samples abroad for analysis might be construed as a breach of the agreement under which the samples were obtained. b) Collaborative projects initiated by outside investigators should be fully funded by these investigators. c) Any collaborative projects directed at a particular gene should require the study of the full material pertaining to that gene; ie, investigators should not be encouraged to study a subsample of what is available for a particular sequence in a way that might satisfy the investigators’ needs but not those of RERF.
7. Through this discussion the workshop participants recognized that there was a dearth of data on the mutagenic effects of radiation at the molecular level to guide the proposed studies, and participants encouraged the collection of such data under whatever auspices seemed most appropriate.
8. An effort was suggested, if feasible, to collect surgical and autopsy samples from the members of the study cohort for possible future studies, as well as to complete the project to establish lymphoblastoid cell lines.
Following are the recommendations of the workshop.
1. The workshop recognized that the traits used as indicators of genetic damage in the previous studies on the genetic effects of A-bomb radiation all ultimately trace back to variation at the DNA level, some more directly than others, and expressed the opinion that it would be useful to attempt to estimate the amount of F1 DNA that had in effect already been screened for mutational damage.
2. The workshop, in view of the recent molecular characterization of many of the genes responsible for “sentinel phenotypes” and the resulting possibility of specifying the total amount of DNA being screened by a consideration of these phenotypes, raised the possibility of further medical examinations of the F1, with particular reference to the occurrence of “sentinel phenotypes.” The sentinel phenotypes should include microdeletion syndromes and an assessment of mental retardation. Given the increased knowledge of genetic diseases, particularly polygenic/multifactor diseases, further, medical evaluations of the F1 cohort (or review of health records) should be considered.
3. The workshop agreed that it would be appropriate to initiate at this time a major pilot study employing the DNA methodologies discussed by C. Satoh, including denaturing-gradient-gel electrophoresis and Southern-blot analysis to look for insertions/deletions/rearrangements and possibly high-resolution electrophoresis for microsatellite loci. The precise efficiencies achieved with the various techniques discussed will need to be evaluated after several years of experience.
4. With respect to the choice of loci for this pilot study, basically two alternatives were recognized: to study a relatively few loci in the entire material or to study in a subsample of the material more loci (perhaps 10-15); the latter would be selected to be representative of various components of the genome. Genes mentioned in the course of the discussion include the loci encoding for the HLA, immunoglobulin, FMR-1, factors VIII and IX, globin genes, several VNTRs, and microsatellite loci. The p53 gene might be a valuable gene to study for comparing the accumulated data on the somatic-mutation analysis of this important human tumor-suppressor gene with any germinal-mutation-spectrum data. It was suggested that the appropriate selection of loci be studied in approximately 50 of the family constellations available for the exposed population and another 50 from the controls.
A minority of the panel expressed the view that it might be desirable to base the initial studies on genes sensitive to radiation mutagenesis, with the thought that if these showed no damage, the study would not be carried further. However, it was agreed that current knowledge did not permit the selection of such genes.
5. The workshop recognized the large body of data on population variation that would result from this study and the complexity of the resulting data base. It therefore recommended that work be initiated on the design of an appropriate data base, which, in view of the desirability of data exchange, should be compatible with the data bases of various national genome projects.
6. In view of the magnitude of the program, and the desirability of collaborative arrangements that would supplement the efforts of RERF staff, guidelines for such collaboration should be developed. Three initial issues with respect to the guidelines were the following: a) Because of local sensitivities in the cities of Hiroshima and Nagasaki, collaborative projects should, if possible, be carried out at RERF. To send such samples abroad for analysis might be construed as a breach of the agreement under which the samples were obtained. b) Collaborative projects initiated by outside investigators should be fully funded by these investigators. c) Any collaborative projects directed at a particular gene should require the study of the full material pertaining to that gene; ie, investigators should not be encouraged to study a subsample of what is available for a particular sequence in a way that might satisfy the investigators’ needs but not those of RERF.
7. Through this discussion the workshop participants recognized that there was a dearth of data on the mutagenic effects of radiation at the molecular level to guide the proposed studies, and participants encouraged the collection of such data under whatever auspices seemed most appropriate.
8. An effort was suggested, if feasible, to collect surgical and autopsy samples from the members of the study cohort for possible future studies, as well as to complete the project to establish lymphoblastoid cell lines.