rs6591536

rs6591536, also known as N183D or Asn183Asp, is a SNP in the olfactory receptor, family 5, subfamily A, member 1 OR5A1 gene. The rs6591536(A) allele encodes the asparagine (N). Individuals vary in their ability to smell various odors, largely due to variations in their olfactory receptors. Carriers of one or two rs6591536(G) alleles can detect a particular compound, β-ionone, at levels two orders of magnitude lower than rs6591536(A;A) individuals. In fact, this study reports that 96% of the observed phenotypic variation is determined by this single SNP, making it nearly a completely Mendelian trait. People with high or low β-ionone sensitivity are found in all populations, and based on this SNP, variability was seen even in Neanderthal populations. Since rs6591536 determines β-ionone odor sensitivity, generally described as "floral", preferences may depend on genotypes at this SNP. The same study cited above found that on average, high-sensitivity individuals were more likely to prefer fragrances and household products containing β-ionone than low-sensitivity individuals, whereas when in food products such as beverages and chocolates, high-sensitivity individuals rated them lower than low-sensitivity individuals. In general, low-sensitivity individuals, i.e. rs6591536(A;A) individuals, were less likely to perceive the β-ionone for good (in scented household products) or for bad (in foods). β-ionone has anti-cancer properties, however it is unknown whether differences in β-ionone flavor sensitivity affect cancer risk by changing the amount of β-ionone people consume.