Hyperosmia is an increased olfactory acuity (heightened sense of smell), usually caused by a lower threshold for odor.
A study by Menashe et al. has found that individuals with a single nucleotide polymorphism variant in the OR11H7P pseudogene have a lower receptor activation threshold for isovaleric acid.
Another study by Keller et al. has found that people with the intact human odorant receptor OR7D4 are more sensitive to androstenone and androstadienone and thus find them unpleasant (individuals with the semi-functional OR7D4 have two non-synonymous single nucleotide polymorphisms in the OR7D4 pseudogene, resulting in two amino acid substitutions).
[5] It has been observed that the inhalation of hydrocarbons can cause hyperosmia, most likely due to the destruction of dopaminergic neurons in the olfactory bulb.
[6] Dopamine antagonists such as butyrophenones or thioridazine hydrochloride were used to treat hyperosmia, but were later discontinued due to undesirable side effects.