Radiation cancer risks passed on, new study suggests

Parental exposure to radiation can cause genetic mutations in the next generation, changes that could lead to diseases such as cancer, according to a new research study.

The work supports earlier findings in Ireland and Britain which suggested that children might experience more illness due to their fathers having been exposed to radiation.

The new study, published in the journal Nature, was carried out by scientists from the University of Leicester and the Vavilov Institute of General Genetics, Moscow.

They found that male mice exposed to non-lethal radiation doses were much more likely to have offspring with detectable genetic mutations, which the researchers said, "confer a predisposition to cancer".

Only male mice were exposed and these were mated with non-exposed females. Resultant male offspring had a six-fold increase in their rate of genetic mutations and female offspring had a 3.5-fold rise in genetic mutations.

"These findings have potential implications for risk evaluation in humans," the Nature authors write. While most radiation risk assessment had focused on the directly exposed individual, "the persistence of instability into the germ line of unexposed offspring of irradiated mice raises the issue of delayed genetic risk".

This new study strongly supports earlier findings by Dr Carmel Mothersill and Dr Colin Seymour of the Radiation and Environmental Science Centre at the Dublin Institute of Technology, Kevin Street. Dr Mothersill, who heads the centre, has been studying "genomic instability" caused by radiation and other stresses since 1982.

A key finding of her work was that radiation-induced instability occurred at any radiation dose, even at the low doses used in diagnostic X-rays.

"Nobody understands why or what mechanism could explain it," Dr Mothersill said yesterday. "It is always the offspring of a father that has been exposed."

Radiation, chemicals and heavy metals have all been shown to induce transgenerational genomic instability, she said.

When the genetic material in offspring becomes unstable, mutations can occur that either kill off the cell line or induce illnesses such as cancer. Dr Mothersill believes many disorders could be attributed to chemical or radiation-induced genomic instability.

"We firmly believe some of the neurodegenerative disorders such as Alzheimer's and Parkinson's diseases are part of the same phenomenon," she said.