How do our genes influence our sense of smell?

The sense of smell is the least researched of our senses – despite the fact that olfactory disorders can significantly impair quality of life and may provide important clues to underlying illnesses. The study analysed the genetic basis of the sense of smell in over 21,000 people of European descent. Particular attention was paid to potential differences between women and men. To this end, researchers used so-called genome-wide association studies, in which the genetic material of large numbers of individuals is compared.

Links between the sense of smell, Alzheimer’s and hormones

“We identified ten genetic regions associated with the ability to detect specific odours – seven of these are new discoveries. Three of the regions also show sex-specific effects, meaning they function differently in men and women,” explains Professor Markus Scholz, lead researcher of the study from the Institute for Medical Informatics, Statistics and Epidemiology at Leipzig University. The findings help to explain why women, for example, perceive smells differently during their menstrual cycle or pregnancy. They could also support efforts to tailor medical diagnoses more closely to biological sex.

Another key finding of the study: “There is a link between the risk of Alzheimer’s disease and the ability to detect odours. This strengthens the evidence that the sense of smell, sex hormones and neurodegenerative diseases are interconnected,” says Franz Förster, first author of the study and an early career researcher at the Faculty of Medicine. The genetic effects identified in the current analysis were each limited to individual odours – there was no single “universal genetic locus” that influenced the perception of multiple smells.

Identifying everyday smells using scent pens

In the Leipzig LIFE Adult Study and other partner studies, participants were asked to identify twelve different everyday smells presented using special scent pens. Their responses were compared with genetic data and analysed in a large-scale meta-analysis led by the Institute for Medical Informatics, Statistics and Epidemiology.

An even larger study is currently under way as part of the German National Cohort (NAKO Gesundheitsstudie), in which Leipzig University is also involved. Around 200,000 people are taking part. Researchers at the Institute for Medical Informatics, Statistics and Epidemiology hope this will soon allow them to examine genetic and sex-specific differences in the sense of smell in even greater detail.