After a scanning the human genome for tiny DNA differences, researchers say they've uncovered clues to several genes involved in alopecia areata, in which patches of hair -- or all hair -- are lost from the scalp or full body.
Yes, yes, we hear you yawn, another day, another whole-genome scan, reporting genes-linked-to-something-we-already-knew-had-a-heritable-component. But to find out what's going wrong, one needs to know what biological processes are involved; so gene studies are very useful, even though practical returns may seem like they take forever to come.
A few things of interest in this one, gleaned from reading the paper and related materials:
1) Some of the implicated genes are involved in various parts of the immune system and include ones suspected or known to be involved in other autoimmune diseases such as Type 1 diabetes and rheumatoid arthritis. The authors note that therapies are already underway targeting biochemical pathways those genes are involved in. So maybe they'd be helpful for people with alopecia as well.
2) The genes didn't seem linked to ones involved in the skin condition psoriasis, explaining why anti-psoriasis therapies that had been tried didn't work very well.
3) Among the identified genes, one -- called ULBP3 -- is normally turned on in the hair follicle (the skin structure from which hair sprouts). But in people with alopecia areata, the activity of this gene was abnormally high.The scientists hypothesize that this up-regulation might act as a signal to immune cells to swoop in for the attack: They note that the protein made by the ULBP3 gene is known to activate certain cells in the immune system -- cytotoxic T cells.
Some alopecia areata facts:
It affects an estimated 5.3 million people -- male and female, various ethnicities -- there's a 2% risk of someone developing it during their lifetime.
When it happens, all kinds of immune cells move into the hair follicle, as if the body has started viewing the area as foreign. But since the stem cells that give rise to hair are not harmed, hair can regrow.
It's been noted that people undergoing trauma or grief can develop whitened hair quite suddenly. Some scientists believe this could be due to the sudden onset of alopecia.
The study, published this week in the journal Nature, reached its conclusion after comparing DNA from 1,054 people with alopecia ariata and 3,278 people without it. It was conducted by a team of scientists at a slew of institutions in the U.S. as well as the United Kingdom and Germany and led by researchers at Columbia University Medical Center.
You'll notice that the link above takes you only to the abstract of the Nature paper: If you want to read more you'll have to cough up. You might like looking at the supplemental information about alopecia and the study that also was posted with the paper. Along with technical details, there is interesting medical background -- for instance, that the condition was described in a 4,000-year-old document from Egypt and that the name was coined by the ancient Greek physician Hippocrates. He called it by the Greek word "alopekia," from the Greek word "alopex," meaning fox (probably because they shed their fur each season or get mange).
For more information about alopecia, visit the website for the National Alopecia Areata Foundation.
-- Rosie Mestel