Bernstein Medical - Center for Hair Restoration - Hair DX Genetic Test
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What are the chances that I will go bald? How bald will I be? Can I know for sure? These are among the most common questions we get from patients in our hair loss consultations. Despite extensive knowledge about the mechanisms and causes of androgenetic alopecia (common baldness), the answers to these questions have been a bit hazy. New research has sharpened the focus on the genetic mix that results in hair loss and has enabled more accurate predictions. A study published in February 2017 in the journal PLoS Genetics identified over 250 gene locations newly linked to hair loss. Using this information, researchers more accurately predicted severe balding compared to previous methods.

Background

We know that susceptibility to hair loss is driven by genetics. One in two men in their 50s experience some degree of balding, with that proportion increasing to over 60% of men aged 60 and over. We also know that one of the most important genes in hair loss, called the androgen receptor (AR) gene, is located on the X chromosome. Outside of that, knowledge of the precise genetic makeup resulting in baldness is sparse and there is wide variation in balding patterns. Some genetic tests, such as the HairDx test, have been developed to predict a patient’s risk of balding, but lack the ability to determine its severity. To date, the best method for predicting the extent of future hair loss is to have an experienced physician take a personal and family history and perform a physical examination that includes an assessment of miniaturization of scalp hair.

Developing a more thorough understanding of the complex genetic relationships that result in hair loss will be important in clinical practice as these relationships may help predict future hair loss and guide methods of treatment.

The Study

Researchers selected a pool of more than 52,000 men with male pattern baldness from UK Biobank. This is a massive database of over half a million people aged 40-69 years with information accumulated from 2006 to 2010. This pool was over four times the size of the previously largest hair loss study. Researchers applied a genome-wide association study (GWAS) to a cohort of about 40,000 men and identified 287 statistically important gene locations (loci) linked to varying degrees of baldness — more than 35 times the eight genetic signals found in the previous largest study.

Using this set of 247 loci on non-sex, or autosomal, chromosomes and 40 loci on the X chromosome, the researchers analyzed the remaining 12,000 men for predictive patterns. The results indicated that the predictive value of using this set of gene loci was 0.78 for severe hair loss, 0.68 for moderate hair loss, and 0.61 for slight hair loss. When the subject’s age was added, the predictive score improved to 0.79 for severe hair loss, 0.70 for moderate hair loss, and 0.61 for slight hair loss. Subjects whose individual scores, based on their genetic makeup, were below the mid-point of the range of scores were significantly more likely to have no hair loss than severe hair loss. By contrast, almost 60% of subjects whose individual scores were in the top 10% of the range of scores were moderate to severely bald.

While the predictions were not extraordinarily accurate – the authors characterized the accuracy as “still relatively crude” – they did show a distinct improvement in predictive accuracy over prior studies.

Summary

Hair loss is a serious concern for many people. Research shows that men with extensive hair loss may experience significant psychosocial impacts such as reduced self-image and reduced social interactions. Some studies have associated baldness with increased risk of prostate cancer and heart disease.

Understanding the complex factors that comprise the genetics of hair loss can help physicians potentially customize treatments based on a patient’s genetic profile and their risk of balding. Beyond that, diagnosing the potential severity of hair loss may help doctors get a head start on treating what could be related life-threatening conditions.

With large databases like UK Biobank, researchers can now drill down into this information and develop increasingly clear, highly granular data sets that can identify complex systems and potentially lead to improved treatments.

References

Hagenaars SP, Hill WD, Harris SE, Ritchie SJ, Davies G, Liewald DC, et al. (2017) Genetic prediction of male pattern baldness. PLoS Genet 13(2): e1006594. doi:10.1371/journal.pgen.1006594

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Q: Is it worth getting the genetic test for balding?

A: You’re referring to Hair DX (hairdx.com), which costs about $150 and came to market in January of 2008 as the first test for androgenetic alopecia, aka male pattern baldness.

The test screens for variations in the androgen receptor gene on the X chromosome, the gene that is associated with male pattern hair loss. The purpose of the test is to identify persons at increased risk of developing hair loss before it is clinically apparent – so that medical intervention can be started early, when it is most effective.

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. It is best to have the test performed under a doctor’s supervision, so that it can be put in the context of other information that the physician gleans through a careful history, physical and a densitometry hair evaluation. As of this posting, genetic testing for hair loss is not permitted in New York State.

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Most medical conditions can best be addressed with early diagnosis. Genetic hair loss is no different. A test now has the ability to identify whether or not you may be genetically predisposed to hereditary male pattern baldness (Androgenetic Alopecia).

The HairDX genetic test offers information that can aid you and your doctor in making an informed decision about the treatment of your hair loss.

This test is not a substitute for an examination by a physician experienced in the diagnosis and treatment of hair loss. It offers one more bit of information that, in the context of other data (such as hair loss pattern, scalp miniaturization and family history) can help guide you and your doctor to formulate an appropriate treatment plan.

How does this test work?

This new genetic test examines genetic variables (SNP) which are responsible for recognizing Androgen hormones in our bodies. These specific genetic variants of the X chromosome (the Androgen Receptor or AR gene) are found in 95-98% of bald men.

These genetic differences are associated with Male Pattern Baldness (MPB) and by identifying them; the onset of MPB might be better predicted. If a person is predisposed genetically to these chromosomal variations, they may be more likely to develop male pattern baldness prior to age forty.

The test consists of a simple swab of the inside of your mouth. The skin cells are then sent to the HairDX clinical laboratory for a confidential analysis.

How accurate is the test in predicting baldness?

HairDX tests for a genetic variant of a gene (the androgen receptor gene) found on the X-chromosome that is present in more than 95% of bald men. Sixty percent of patients with this variant experience male pattern baldness before the age of 40. Therefore, if a person has this gene, they would have an increased risk of significant pattern baldness.

Another, less common genetic variant of the same gene (present in about 1 in 6 men) indicates a greater then 85% likelihood that a person will not experience early onset pattern baldness. If a person is found to have this gene, they are unlikely to become very bald.

Why is the genetic test not 100%?

The androgen receptor gene identified thus far is only one of a number of genes that affect hair loss.

How does the test compare to information obtained from a history and physical exam by your physician?

An assessment of scalp miniaturization by an experienced physician using a densitometer, combined with a history and physical, appears to be a far more reliable way of predicting future hair loss. The genetic test can complement this information, but does not replace it.

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