A single nucleotide polymorphism, often called SNP (pronounced “snip”) for short, is a single change in the smallest portion of our DNA - chemicals called nucleotides that bond together to form the ‘ladder’ of the double helix shape. Genetic and genomic testing use these SNPs to help locate places in a person’s genetic code that could cause them to be more susceptible to certain health conditions.
SNPs are common in human DNA, occurring about once every 1,000 nucleotides. This means there are roughly 4 to 5 million SNPs in the average person’s genome. Most of these genetic variations have no direct relation to disease risk and instead reflect the uniqueness of human diversity, however when a SNP occurs in an area of the genome associated with disease, it can have a direct role in affecting a person’s risk of developing a given condition.