Your DNA is continually damaged by sources both inside and outside your body. One especially severe form of damage called a double-strand break involves the severing of both strands of the DNA double helix.
Double-strand breaks are among the most difficult forms of DNA damage for cells to repair because they disrupt the continuity of DNA and leave no intact template to base new strands on. If misrepaired, these breaks can lead to other mutations that make the genome unstable and increase the risk of many diseases, including cancer, neurodegeneration and immunodeficiency.
