The genome found in every cell of our body contains over 20 thousand genes and over 3 billion letters of DNA that sustains life, shapes who we are and determines our risks of having a disease. CRISPR/Cas (clustered regularly interspaced palindromic repeats) is a recently discovered antiviral defence system in bacteria that has become the favorite set of tools to edit and correct any diseased genome and change any sequence of DNA in precisely chosen genomic location performed not in a test tube but within the nucleus of our living cell.