Heritable effects of pre-conceptual radiation exposure

 

What are we doing?

We are analysing the chromosomes of the descendants of nuclear test veterans in order to identify any constitutional chromosome aberrations. Constitutional aberrations relate to the genetic constitution you were born with and occur rarely in the general population. If any abnormalities are found then these will be correlated with known clinical chromosomal disorders.

Why are we doing this?

The British Government undertook a series of atmospheric nuclear weapons tests at various sites in Australia and the South Pacific between 1952 and 1958. Associated with these tests was an experimental programme in which radioactivity was dispersed into the environment. This programme ended in 1963 although operations continued through to 1967. Additionally, UK personnel participated in a series of American tests based at Christmas Island in 1962. It is estimated that over 20,000 UK servicemen participated in at least one of these British and American tests.

An ongoing concern within the nuclear test community has been whether veterans of these programmes could have received sufficient radiation exposure to cause genetic damage in them. This concern extends to whether they might also have passed on genetic alterations to their children, thereby potentially affecting their family’s health. Genetic damage can increase the risk of developing various diseases such as cancer, however of the studies carried out to date, no clear link between participation at nuclear test sites and increased mortality (death) or cancer occurrence relative to control populations, has been found (Muirhead et al. 2004, Darby et al. 1988b, Darby et al. 1993, Kendall et al. 2004). Reports of an increased incidence of miscarriage and genetic disorders in children of nuclear test veterans are largely anecdotal.

This question of adverse health effects in the children of radiation-exposed parents remains outstanding. The consensus from international epidemiology (principally human population studies of Japanese A-bomb survivors) is that presently no conclusive evidence exists, yet this is tempered by some evidence from cellular and animal studies that support the presence of detrimental outcomes in offspring as a result of parental exposure to radiation. Accordingly further research is justified.

What does this research involve?

Blood samples of nuclear test veteran’s descendants are being collected and cytogenetic analysis performed. This involves culturing peripheral blood lymphocytes (growing blood cells) under different conditions for chromosome analysis.

Constitutional abnormalities (i.e. the same chromosome aberration is present in every blood cell of a person) will be identified if present, using a technique for analysing chromosomes called G-banding. If any abnormalities are found then these will be correlated with known clinical chromosomal disorders.

If a chromosomal disorder is identified then this could be a consequence of a newly arising change in the germline or due to an inherited mutation passed from either their father or the mother. Accordingly, further investigations to ascertain the parental origin would take place.

What can we learn from this study?

This study will determine whether the amount of chromosome aberrations in children is similar or different between test veteran and control veteran groups. This will provide important new information on likelihood that any exposure in a test veteran parent could be associated with changes to the genome of their children.

Changes to the genome may:

  • have no effect on the health of the individual
  • have an effect which is clinically-recognised
  • increase the risk or likelihood of a clinical effect

What this study cannot tell us

Our study will not provide any direct information that could be used to relate any medical condition in an individual or individual family to exposure to ionising radiation.

References

Muirhead CR, Kendall GM, Darby SC, Doll R, Haylock RG, O’Hagan JA, Berridge GL, Phillipson MA, Hunter N. (2004) Epidemiological studies of UK test veterans: II. Mortality and cancer incidence. Journal of Radiological Protection 24(3):219-41. Doi: https://iopscience.iop.org/article/10.1088/0952-4746/24/3/002

Kendall, G M, Muirhead, C R, Darby, S C, Doll, R, Arnold, L, & O’Hagan, J A (2004). Epidemiological studies of UK test veterans: I General description. Journal of Radiological Protection, 24(3): 199-217. Doi: https://iopscience.iop.org/article/10.1088/0952-4746/24/3/001

Darby SC, Kendall GM, Fell TP, O’Hagan JA, Muirhead CR, Ennis JR, Ball AM, Dennis JA, Doll R. (1988) A summary of mortality and incidence of cancer in men from the United Kingdom who participated in the United Kingdom’s atmospheric nuclear weapon tests and experimental programmes. Br Med J (Clin Res Ed). 30; 296-332. doi: https://doi.org/10.1136/bmj.296.6618.332

Muirhead CR, Bingham D, Haylock RGE, et al.  (2003) Follow up of mortality and incidence of cancer 1952–98 in men from the UK who participated in the UK’s atmospheric nuclear weapon tests and experimental programmes. Occupational and Environmental Medicine, 60:165-172.doi: 10.1136/oem.60.3.165