Answers to frequently asked questions about hair loss genetics.
Q: There was a retrospective study by Lotufo et al. linking male pattern baldness to heart disease. Do you think there are other links like this for androgenetic alopecia?
A: Family studies revealed both the androgen receptor locus on the X chromosome, as well as a new locus on chromosome 3q26. Association studies performed in two independent groups revealed a locus on chromosome 20 (not near any known genes) as well as the androgen receptor on the X chromosome. Read on for the rest of the answer.
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.
The HairDX genetic test for hair loss offers information that can aid you and your doctor in making an informed decision about the treatment of your 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 it work? How accurate is the test? How does the test compare to information obtained from a history and physical exam by your physician? Dr. Bernstein answers these questions and more on the HairDX genetic test for hair loss.
Q: What are the genes that cause male pattern baldness?
A: At this time 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 Androgen Receptor (AR) gene carried on the x-chromosome and the second is a non-sex chromosome 20p11.
Q: Why do some people have a full head of hair into their seventies or eighties and others start to go bald in their late teens or early twenties?
A: The cause is genetic and this poly-genetic trait can be inherited from the mother’s side, the father’s side, or both.
There is an old wives’ tale that it is inherited only from the mother’s parents. Although the inheritance can come from either side, it is actually greater from the mother’s side – but only slightly.