Flaws in the genetic code carried in the DNA of our cells are a source of many disease states. These flaws are introduced by a number mechanisms including gamma rays, x-rays, radiation damage, chemical damage, poor fidelity in cell duplication or invasively by retro-viruses. These genetic mutations, when they are not fatal because they damage vital proteins, propagate to successive generations and accumulate over time.
Mutations are not a mechanism for creating new genetic information as evolutionists fancifully envision, or as portrayed in fiction like the Marvel X-men universe. Mutations are a source of degradation of the critical information needed to create proteins, the complex machinery of life. Scientists have divised a gene therapy technology that has the promise to revolutionize treatment of disease called CRISPR. It can be used to recognize known faulty DNA sequences in cells and snip them out facillitating their replacement with corrected DNA.
This short video does a nice job of explaining how it works.
This advancement has enormous medical potential, but also will pose serious ethical questions for those who will inevitably be tempted to redesign organisms. Jurassic Park is one step closer.
Atheist to Elder 