According to editorials in August of 2012 from Sayer Ji of GreenMedInfo, and Elizabeth Renter of NaturalSociety, it has been estimated that less than 1% of all diseases are caused by flawed genes! Because the influence of our environment on genes (epigenetics) usually determines the expression of our genes, our lifestyle becomes very important in determining our health. Food, exercise, thoughts, and environmental exposures are all powerful modifyers of genetic expression. We even know that GMO foods can silence certain genes.
In the case of cystic fibrosis, we know that the abnormal folding of DNA can be corrected by a diet that includes cayenne, soy, and turmeric!