Key Questions Answered
Q: What did the study discover about the genetics of smell?
A: Researchers identified 10 genetic regions tied to the ability to detect specific odors, seven of which were previously unknown.
Q: How do sex differences play a role in smell perception?
A: Three of the genetic regions showed sex-specific effects, potentially explaining why smell sensitivity changes during menstruation or pregnancy.
Q: What’s the connection between smell and Alzheimer’s?
A: The study found a genetic link between odor detection and Alzheimer’s risk, suggesting that the sense of smell may be an early indicator of neurodegeneration.
Summary: A major genetic study of over 21,000 Europeans has identified 10 regions in the genome linked to how we perceive specific odors—seven of which are newly discovered. Three of these genetic regions function differently in men and women, helping explain hormone-driven changes in smell sensitivity.
The research also uncovered a genetic connection between odor perception and Alzheimer’s risk, further linking olfaction to brain health. These findings could inform sex-specific diagnostics and early screening for neurodegenerative disease.
Key Facts
- New Genetic Links: 10 genetic regions tied to smell perception were identified, 7 of them newly discovered.
- Sex-Specific Effects: Three regions differed in activity between men and women, likely influenced by hormonal factors.
- Alzheimer’s Insight: A genetic association was found between odor detection and Alzheimer’s risk.
Source: University of Leipzig
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.
About this genetics and olfaction research news
Author: Anne Grimm
Source: University of Leipzig
Contact: Anne Grimm – University of Leipzig
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Genome-wide association meta analysis of human olfactory identification discovers sex-specific and sex-differential genetic variants” by Markus Scholz et al. Nature Communications
Abstract
Genome-wide association meta analysis of human olfactory identification discovers sex-specific and sex-differential genetic variants
Smelling is a human sense, expressing strong sexual dimorphisms. We aim to improve the knowledge of the genetics of human olfactory perception by performing an exploratory genome-wide association meta-analysis of up to 21,495 individuals of European ancestry.
By sex-stratified and overall analysis of the identification of twelve odours and an identification score, we discovered ten independent loci, seven of them novel, with trait-wise genome-wide significance (p < 5 × 10−8) involving five odours.
Seven of these loci, including four novel ones, are also significant using a stricter study-wide significance threshold (p < 3.85 × 10−9). Loci were predominantly located within clusters of olfactory receptors.
Two loci were female-specific while one was sex-differential with respective candidate genes containing androgen response elements. Two-sample Mendelian randomization was applied to search for causal relationships between sex hormones, odour identification and neurodegenerative diseases.
A causal negative effect was detected for Alzheimer’s disease on the identification score.
These findings deepen our understanding of the genetic basis of olfactory perception and its interaction with sex, prioritizing mechanisms for further molecular research.
