rs8176719

ABO blood group rs8176719 represents a site in the ABO gene, often referred to as either c.261delG or, less commonly, c.260_262insG, and it is a key SNP in determining blood group type O status. An allele that encodes either a blood group type A or type B will have a (G) at this SNP site, i.e. such an allele will be rs8176719(G). If a one-base deletion has occured at this site, removing this nucleotide all together, the corresponding allele is considered to be rs8176719(-) and encodes the most common blood group type O allele. However, an individual will typically only be blood group type O if they are carry two copies of (are homozygous) for this deletion, in other words, if their genotype is rs8176719(-;-). If they carry one copy, they could be blood type A, or blood type B (but are unlikely to be type O). A person who is rs8176719(G;G) is likely to be of blood type A, B, or AB, but due to the existence of (rare) nonfunctional O alleles brought about by (nondeletional) mutations at other positions than rs8176719, they could at least theoretically still be phenotyped as type O. The determination of blood group types A, B, and AB through SNP analysis is reflected in the appropriate genosets.