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Wednesday, May 12, 2010

Hair Genetics and HairDX genetic test:

Hair Genetics and HairDX genetic test:           

Male or Female Patter Hair Loss aka Androgentic Alopecia (common Baldness) is genetic and has Poly genetic trait (that means there are more than one genes responsible for this condition) and there is an old wives’ tale that it is  inherited from Mother’s side but it is proven that it can be inherited also from father’s side although there is slightly higher chance of inheritance from Mother’s side. The genes that actually cause hair loss are still unknown however, there are two gene loci, recently identified, that appear to be associated with common baldness. The first is on the “Alteration in Androgen Receptor (AR) gene” carried on the x-chromosome and the second is a “non-sex chromosome 20p11” 

 

The variations result from small changes in the number or types of DNA building blocks (base pairs) that make up the AR gene. These genetic changes appear to be most frequent in men with hair loss that begins at an early age. Researchers believe that AR gene variations may increase the activity of androgen receptors in the scalp. Although androgenetic alopecia is related to the effects of androgens on hair growth, it remains unclear how changes in the AR gene increase the risk of patterned hair loss in men and women with this condition.

Since AR gene are on X chromosome – a sex linked chromosome (XX I females and XY in males) it is transmitted from Mother Side and the non sex linked 20p11 genes on 20th chromosome can be transmitted from both mother and father side.

If you have both the risk variants we discovered on chromosome 20 and the unrelated known variant on the X chromosome, your risk of becoming bald increases sevenfold."

"What's startling is that one in seven men have both of those risk variants. That's 14 per cent of the total population!"

  
What is the HairDX genetic test?


The HairDX (http://hairdx.com ) genetic test for Pattern Hair Loss (Androgenetic Alopecia) is a screening test for predicting hair loss. It allows diagnosis in an earlier or preclinical stage, so that treatment can be initiated at a time when intervention by medications and finasteride has a greater likelihood of success. Current diagnostic methods like videoscopy hair thinning is visible when you have probably lost about 50% of your hair in that area of your scalp. Because, the only FDA approved medications to combat hair loss, minoxidil and finasteride, are most effective at stabilizing hair loss rather then re-growth, the earlier you can predict Hair Loss, the more likely you are to save your hair. So early medical intervention prior to visible signs of hair loss, allowing you to retain your hair. 

 


The HairDX genetic test for Pattern Hair Loss is most appropriate for men and women 18 years of age or older who are concerned about hair loss esp when there is a familial history of hair loss.



Your genetic sample is collected using a cheek swab by your doctor and the sample is mailed for analysis to the HairDX laboratory. Once the genetic analysis is complete, your test results will be reported to your doctor.
 



The HairDX genetic test for Female Pattern Hair Loss provides women with a score, called the CAG repeat score. A smaller CAG test score is associated with a higher risk for significant hair loss (Ludwig grade II or III hair loss) while a larger test score is associated with a lower risk for hair loss. 

 



Women who have a smaller CAG test score should be advised that they are at a higher risk for significant hair loss (Ludwig grade II or III hair loss). According to scientists, the percentage of the female population with a CAG test score of 15 or less, NOT suffering from a Ludwig grade II or III hair loss was only a 2.3%.

These women may wish to consult with a physician specializing in hair restoration, who can develop a plan to monitor and treat early hair loss. For example, such women may be good candidates for minoxidil, especially if treatment is started early.

In contrast, women who have a larger CAG test score can be reassured that they are at low risk for significant hair loss. This avoids unnecessary concern or expense over premature hair loss. 




Interpretation for Men:


The HairDX genetic test for Male Pattern Hair Loss provides information on the presence of a specific variation in the androgen receptor gene (AR), found on the X chromosome. The variant AR causes changes in the hair follicle's response to dihydrotestosterone, leading to alterations in the hair growth cycle. 

 

  • The variant AR is found in more than 95 percent of bald men—60 percent of men who have the variant AR will develop baldness by age 40.
  • HairDX also provides information on a less common AR variant that predicts a very low risk of early-onset androgenetic alopecia—more than 85 percent of men who have this variant will not have hair loss by age 40.

Men who test positive for the variant AR should be advised that they are at a high risk of developing early-onset Male Pattern Hair Loss. These men may wish to consult with a physician specializing in hair restoration, who can develop a plan to monitor and treat early hair loss. For example, such men may be good candidates for finasteride (Propecia), especially if treatment is started early.

In contrast, men without the variant AR can be reassured that they are at low risk of early-onset Male Pattern Hair Loss. This avoids unnecessary concern or expense over premature hair loss.



Hair DX (hairdx.com), costs about $150.  It is important to realize that, at this point, there is just an association with this gene and hair loss; the cause and effect has not been proven and the association is not anywhere near 100%. A danger is that patients may overreact to the relatively incomplete information that the test provides. 



New Gene in Hair Loss APCDD1

A team of researchers lead by Dr.Angela M. Christiano, Ph.D., professor of dermatology and genetics & development at Columbia University Medical Center found that the gene, called APCDD1 ( located in a specific region on chromosome 18), which causes a progressive form of hair loss beginning in childhood (known as hereditary hypotrichosis simplex). The disease is caused by a phenomenon called hair follicle miniaturization -- the same key feature of male pattern baldness. When hair follicles go through this miniaturization process, they shrink or narrow, causing the thick hair on the head to be replaced by thin, fine hair, known as "peach fuzz."

The identification of this gene underlying hereditary hypotrichosis simplex has given an opportunity to gain insight into the process of hair follicle miniaturization, which is most commonly observed in male pattern hair loss or androgenetic alopecia It is important to note that while these two conditions share the same physiologic process, the gene discovered for hereditary hypotrichosis does not explain the complex process of male pattern baldness.

APCDD1 inhibits a signaling pathway known as the Wnt signaling pathway, to turn on or off hair growth in mice, but, until now, the pathway did not appear to be involved in human hair loss. This finding is significant because it provides evidence that hair growth patterns in humans and in mice are more similar than previously believed.

"We have at last made a connection between Wnt signaling and human hair disease that is highly significant," said Dr. Christiano. "We have years of beautiful data in our field about hair growth in mice, but this is the first inroad into showing that the same pathway is critical in human hair growth. This is the first mutation in a Wnt inhibitor that deregulates the pathway in a human hair disease."

These findings suggest that treatments involving manipulating the Wnt pathway would be non-hormonal, which may enable many more people suffering from hair loss to receive such therapies.



Gene That Regulates Hair Growth: Lhx2

Activation of the gene Lhx2 leads to increased hair growth. This is shown by Leif Carlsson's research team at Umeå University in Sweden. The transcription factor Lhx2 as an important regulator of hair formation. The Lhx2 gene is active during the hair follicle's growth phase and is turned off during the resting period. Lhx2 is expressed periodically, primarily in precursor cells that are distinct from the cells in the bulging region of the follicles. Hair follicles in which Lhx2 has been inactivated cannot produce hair. Moreover, the activation of the Lhx2 gene in hair follicles has been shown to activate the growth phase and hence the formation of hair. Thus, Lhx2 is a gene that is important for the regulation of hair growth.

In stark contrast to previously published research findings from other teams of scientists, Leif Carlsson and his colleagues found that Lhx2 is primarily expressed outside the so-called bulge region of the hair follicle, where the follicle's stem cells are found. The Umeå researchers have also shown that Lhx2 is necessary for the hair follicle's growth (anagen) phase to proceed and for the hair follicle's structuring. Moreover, transgenic expression (gene or genetic material that has been transferred naturally or by any of a number of genetic engineering techniques from one organism to another) of Lhx2 after birth is sufficient to activate the growth phase and stimulate hair growth.



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