Wednesday March 2 2016
A genetic marker that turns hair grey has been found by scientists
"A cure to dye for … the end of grey hair is in sight," says The Daily Telegraph.
Several other media outlets have also reported enthusiastically about the discovery of a gene for grey hair, and how this could pave the way for new treatments to prevent – or reverse – greying.
The stories are a based on a study that analysed the DNA sequence of more than 6,000 people from Latin America to try to identify genetic markers associated with hair features, such as greying and balding.
The researchers found 18 genetic markers associated with facial or head hair, 10 of which had not previously been linked to hair traits.
However, though these markers were associated with the colour, texture, density and distribution of hair, we don't know whether they have a direct influence on these traits.
It is likely that many different genetic markers and associated genes affect our hair, and it is too early to herald a cure for grey hair based on the findings of this study alone.
Right now there's nothing we can do to alter the genetic make-up of our hair. Even if the genetics were fully understood, other factors, such as age, contribute to hair turning grey
Where did the story come from?
The study was carried out by researchers from the University of London, Universidad de Oviedo in Spain, and other international institutions.
It was funded by the Leverhulme Trust, Universidad de Antioquia in Colombia, Ministerio de Economia y Competitividad and Instituto de Salud Carlos III in Spain, and Banco Santander, through its Santander Universities Global Division.
The study was published in the peer-reviewed scientific journal, Nature Communications. It's available to read online for free.
The media gave wide and varying coverage of this research. Most of the reporting focused on the discovery of a gene for grey hair and the possibility of new products being developed to halt greying.
The study's other findings – for example, on facial hair density and distribution – were mostly mentioned in passing, if at all.
What kind of research was this?
This was a genome-wide association study, a type of case control study. It aimed to look at the genetic variations associated with head and facial hair features, such as greyness and balding.
Genome-wide association (GWA) studies involve using genetic material collected from large numbers of people.
Researchers can then scan specific single letter variations in the DNA to try to identify those associated with particular diseases or characteristics.
It is well known there is great variation among humans in the colour and distribution of their body hair. Head hair appearance is highly heritable and shows distinct geographic variation between populations.
For example, variation in hair colour is mostly a feature of western European populations, and straight hair is not found in most African populations.
This study aimed to further our understanding of the genetic basis of this variation.
What did the research involve?
The study involved identifying genetic associations for hair characteristics in a Latin American population.
The researchers included a sample of 6,630 men and women from Brazil, Colombia, Chile, Mexico, and Peru.
They recorded the scalp hair features of the participants, such as hair colour, curliness and balding. They also looked at facial hair characteristics, such as beard, eyebrow and monobrow thickness.
They then analysed the genetic material obtained from blood samples, looking at around 700,000 single letter variations in the DNA sequence, called single nucleotide polymorphisms (SNPs).
The researchers looked at which hair traits were associated with each other, as well as age, gender and ancestry. They then identified those DNA variations with the most association with different hair traits.
They looked at the position of these DNA variations and what genes were nearby, as these genes might be responsible for the links seen.
They also looked at what the genes did to see how they might be able to affect hair. They estimated European, African and Native American ancestry in the study population.
What were the basic results?
The researchers found links between certain pairs of traits:
- beard density and eyebrow density – including having a monobrow
- beard density and balding
- beard density and hair greying
- hair greying and balding
Looking at the effect of age and gender, age was significantly associated with hair greying – this link was particularly strong – as well as balding, beard distribution and eyebrow thickness, as might be expected.
Gender was found to be linked with both hair colour and balding. European ancestry was linked with hair colour.
The researchers identified 18 single letter variations in the DNA sequence associated with hair features, including 10 that had not been linked to these traits before.
The newly identified DNA variations included some for greying hair, facial hair distribution and density, and the position and distribution of scalp hair.
The DNA variation associated with hair greying was previously found to be linked to pigmentation of the skin, hair and eyes.
It lies within a gene called IRF4 in a region that does not include instructions for making protein, but the variant might influence how active the gene is.
In particular, one of the DNA variations associated with scalp hair shape was found to lie in the PRSS53 gene and was predicted to affect the enzyme this gene produces. The enzyme is found in the outer root sheath of the hair follicle.
The presence of the DNA variation altered the way the cells processed and secreted it. This suggests this DNA variation could have a direct influence on the shape and distribution of hair on the scalp.
How did the researchers interpret the results?
The researchers concluded that, "The analyses presented here have enabled us to expand substantially the set of gene regions known to impact on variation in human head hair appearance."
This study identified 18 DNA variations associated with hair characteristics like greying and beard and scalp hair density in a large Latin American sample.
These types of studies are valuable in being able to examine the DNA sequence of thousands of people, and identify sites within DNA that may be associated with the presence of diseases or other characteristics.
This approach is generally used where many different genes – as well as environmental factors – are thought to contribute to a trait.
However, though many DNA variations may be associated with a trait, they don't always have a direct effect on gene activity. As such, each individual study is unlikely to provide the whole answer.
There may be other DNA variations associated with hair characteristics this study hasn't identified. In particular, given that this study looked at a Latin American population, studies of other populations may find other DNA variations and associated genes.
There is nothing we can do to alter our hair trait genetics at present. Much more research is needed for researchers to fully understand the genetics of hair greying, and possibly start to develop treatments based on this.
Don't forget, our age plays a huge part in hair greying, and any potential treatments may not be able to combat this factor.
While the research is of interest in understanding the genetics of hair, it has no current practical implications for anyone wanting to banish their grey hair. A cure for grey hair is not yet in sight.