US researchers have found a gene mutation that causes a progressive type of hair loss known as hereditary hypotrichosis simplex and say their discovery is likely to affect research and improve treatments for different types of hair loss, including male pattern baldness.
A paper on the discovery, by investigators from Columbia, Rockefeller and Stanford Universities in the US, and research centers in Italy and Switzerland, was published online in the 15 April issue of Nature.
The progressive hair loss of hereditary hypotrichosis simplex begins in childhood through a process called hair follicle miniaturization, which also occurs in male pattern baldness or androgenetic alopecia. The process causes hair follicles to shrink so the hair they produce gradually becomes thinner and thinner, until a thick head of hair eventually becomes what is known as “peach fuzz”.
In this study, the researchers found that the gene APCDD1 causes hereditary hypotrichosis simplex and thus gives some insights into hair follicle miniaturization. But, they pointed out that this does not mean the same gene causes male pattern baldness, even though it also involves hair follicle miniaturization.
Lead author Dr Angela M. Christiano, professor of dermatology and genetics and development at Columbia University Medical Center, said in a statement:
“It is important to note that while these two conditions share the same physiologic process, the gene we discovered for hereditary hypotrichosis does not explain the complex process of male pattern baldness.”
For the study, Christiano and colleagues analyzed genetic data from families from Pakistan and Italy with hereditary hypotrichosis simplex and found they shared a particular mutation of APCDD1.
The gene occurs in a region of chromosome 18 that has already been linked to other forms of hair loss, including male pattern baldness or androgenetic alopecia and alopecia areata.
The researchers also found the gene blocks a signalling pathway called Wnt, which has been known for some time to control hair growth in mice, but until this study it was not clear if it had the same effect in humans.
They concluded that as APCDD1 is expressed in a broad repertoire of cell types, their discovery may imply that the gene is also involved in diverse other biological processes regulated by Wnt signalling.
Christiano said the discovery was highly significant because it is the first evidence that Wnt is is critical in human hair growth.
“Furthermore, these findings suggest that manipulating the Wnt pathway may have an effect on hair follicle growth – for the first time, in humans,” she added, explaining that unlike current treatments for hair loss that block hormone pathways:
“… treatments involving the Wnt pathway would be non-hormonal, which may enable many more people suffering from hair loss to receive such therapies,” said Christiano.
“APCDD1 is a novel Wnt inhibitor mutated in hereditary hypotrichosis simplex.”
Yutaka Shimomura, Dritan Agalliu, Alin Vonica, Victor Luria, Muhammad Wajid, Alessandra Baumer, Serena Belli, Lynn Petukhova, Albert Schinzel, Ali H. Brivanlou, Ben A. Barres and Angela M. Christiano.
Nature 464, 1043-1047, Published online 15 April 2010
Source: Columbia University Medical Center.
Written by: Catharine Paddock, PhD