A single nucleotide polymorphism (SNP pronounced "snip") is a DNA polymorphisms at the level of a single nucleotide, a single base mutation in DNA. SNPs are ‘conserved’ across the genome and represent the most simple form and most common source of genetic polymorphism in the human genome: 90% of all human DNA polymorphisms are associated with SNPs and variation frequency is about 1 every 1000bp in the human genome (Sachidanandam et al.,2001).

The SNPs in the genome can affect gene functions, protein structure or expression and for these reasons they are used as markers in genetic disease studies (Kim & Mishra, 2007).

It’s sometimes possible to correlate a SNP with a particular trait or disease: susceptibility to disease may also be described as an ‘unfortunate trait’ that can be assessed checking if the mutated (unfortunate) polymorphism is carried in both alleles.

SNPs testing can be applied to:

• Diagnostics / risk profiling
• Drug response prediction
• Gene function identification

Several SNPs have been associated to genetic susceptibility to different diseases and disorders like for example:

·         Hypertension

·         Fibrinolysis

·         Myocardial infarction

·         Ischemic stroke

·         Cancer

·         Metabolic disorders