Twin pairs and their siblings rated the intensity of the odorants amyl acetate, 
androstenone, eugenol, Galaxolide, mercaptans, and rose (N = 1573). Heritability 
was established for ratings of androstenone (h (2) = 0.30) and Galaxolide (h(2) 
= 0.34) but not for the other odorants. Genome-wide association analysis using 
2.3 million single nucleotide polymorphisms indicated that the most significant 
association was between androstenone and a region without known olfactory 
receptor genes (rs10966900, P = 1.2 × 10(-7)). A previously reported association 
between the olfactory receptor OR7D4 and the androstenone was not detected until 
we specifically typed this gene (P = 1.1 × 10(-4)). We also tested these 2 
associations in a second independent sample of subjects and replicated the 
results either fully (OR7D4, P = 0.00002) or partially (rs10966900, P = 0.010; N 
= 266). These findings suggest that 1) the perceived intensity of some but not 
all odorants is a heritable trait, 2) use of a current genome-wide marker panel 
did not detect a known olfactory genotype-phenotype association, and 3) 
person-to-person differences in androstenone perception are influenced by OR7D4 
genotype and perhaps by variants of other genes.