Well, if its in your genetic code, there is a high chance you will have the disease. However, its not a 100%. Genes can be turned on and off. The environment can certainly turn on a gene and in this case a the disease. Living in a healthy place, with a healthy lifestyle will certainly lower your risk of having the disease. If you are really interested in this, you should go to this site, it has all the recent news about all fields of science. Perhaps you will find some new discovery about how genes turn on and off
http://www.sciencenewsnmore.synthasite.com
