Genetics 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. These individuals are<unk>  for this single odorant. 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). There has not yet been extensive research into the genetic background of those with general<unk> , rather than for just a single odorant. Environmental There has not been extensive research into environmental causes of<unk> , but there are some theories of some possible causes. In a study by Atianjoh et al., it has been found that amphetamines decrease levels of dopamine in the olfactory bulbs of rodents. On this basis, it has been hypothesized that amphetamine use may cause<unk>  in rodents and humans, but further research is still needed. Anecdotal support for the belief that amphetamines may cause<unk>  comes from Oliver Sacks's account of a patient (who he later revealed to be himself) with a heightened sense of smell after taking amphetamines. It has been observed that the inhalation of hydrocarbons can cause<unk> , most likely due to the destruction of dopaminergic neurons in the olfactory bulb. Methotrexate, administered in the treatment of psoriasis, has been known to cause<unk> , and may be more likely to do so in patients with a history of migraines. However, this is only an observation and not part of a study; therefore, it is yet to be verified.
Hyperosmia
Anosmia
Polydipsia
Hypohidrosis
Dysosmia
Nocturia
Hyperhidrosis
Adipsia