The human genome project closed at the end of the year 2000 has provided with the complete list of all genes present in our genome and that contribute to the organization of a complex organism such as the human being. This immense knowledge will have only a limited impact on human health unless we can acquire deep knowledge on the functional role of each specific gene. At the moment, in fact, only approximately 10% of total genes have a known function, while the remaining 90% is identified on the basis of the DNA sequence, but their function is totally unknown. As matter of fact, the post genomic era started in this millennium has the challenge to decipher the function of all human genes and establish their role in physiopathology.