Possible teratogenic effect of low doses of ionizing radiation

(G.I.Lazjuk, I.O Zatsepin, R.D Kkmel, I.L Babicheva) Belarus Institute for Hereditary Diseases, Republic of Belarus

The following conclusions were made using the dataof long-term of possible genetic effects of the Chernobyl accident among Belaruspopulation including over 40 000 of newborns and fetuses with congenital malformations and basing on the data of study of embryonic development failures including more than 43 000 of medical abortions with ~ 3 000 of those from the areas heavily contaminated by radionuclides originating the Chernobyl NPP fallout.

Radiation exposure of the married couples and fetuses included in the study generally could be considered as low dose radiation. An increase of prevalence of embryonic development failures, firstly observed in 1987 continues as in contaminated, as in control areas. The reasons of this increasing trend might be multifactorial and deserves further investigations.

Relative risk of “ mandatory registration” congénital malformations in the area with 137 Cs contamination exceeding 555 kBq/m2 increased from 1.02 (95% CI :0.85 to 1.24) in pre-Chernobyl period to 1.41 (95% CI :1.19 to 1.66) in 1987-1990)

Teratogenic effect due to de novo mutations found for Down’s syndrome cluster registered in January of 1987 and for significant increase of the prevalence at birth of dominant mutations ( multiple congenital malformations, reduction defects of limbs and polydactily)observed within the first 4 years after the accident in the areas with contamination level over 555 kBq/2.

Direct teratogenic effect of the radiation exposure of fetuses due to the Chernobyl release was shown using the data of Belarus registry for anencephaly and delay of head grows confirmated by head circumference deficiency found among 4,1% of newborns with the period of fetal development spent in heavily contaminated regions of Gomel and Mogilev regions of Belarus.