What is a genetic polymorphism or SNP?

A genetic polymorphism or SNP is a variation at a specific position in the DNA that is present in a significant proportion of the population, at least 1%. These variations consist of a change of one nucleotide (adenine, guanine, cytosine or thymine) to a different one within the genome.

A polymorphism may have no effect, but some, usually located in coding or regulatory regions of the genome, may have consequences on the phenotype. The phenotype is understood as the expression of the genotype that can be observed (not only externally, but also e.g. biochemically) and is partly determined by the environment. These polymorphisms affect, for example, our susceptibility to certain diseases or drug metabolism, which is the basis of the tellmeGen study.

By consensus, each of these variants is assigned an rs code (Reference SNP cluster ID or rsID) used in research and reference databases (such as dbSNP). This code can be found in the technical details of each of the items.

Genome-wide association studies (GWAS) are an approach used in genetic research to associate specific genetic variations with certain diseases or conditions. This method involves analysing the genomes of a large number of different people and looking for markers predictive of a certain condition.