How Genes Cause Hair Loss: An In Depth Look

Updated: Jul 9, 2020

Hair loss can be the result of many different factors including stress, thyroid issues, and nutritional deficiencies, but the most common cause of hair loss is androgenic alopecia.

Genes have been shown to play a large part in the development of androgenic alopecia, but there are a lot of misconceptions about how. Let’s dig deeper.

A quick summary of androgenic alopecia

Referred to as male or female pattern baldness, androgenic alopecia is a genetic condition.

The name derives from the way androgens interact with the body. Androgens are a type of hormone, and dihydrotestosterone (DHT) is a type of androgen. DHT, being a byproduct of testosterone, is the hormone responsible for causing hair to undergo the miniaturization process. Miniaturization is a term that essentially means the hair follicles are slowly dying.

Alopecia is defined by Oxford dictionary as “the partial or complete absence of hair from areas of the body where it normally grows; baldness.” Hence “androgenic alopecia”, or baldness caused by androgens.

We know for the most part how androgenic alopecia occurs, but we are still trying to discover why. Scientists, however, have been able to determine that genetics have a strong influence as to whether or not you will go bald.

The AR gene

Scientific studies (1,2) have most commonly found that a protein coding gene called the “AR” gene plays a role in androgenic alopecia.

The AR gene is responsible for instructing the body to make proteins called androgen receptors. The androgen receptors are responsible for making sure the body responds appropriately to different androgens, including DHT, and are present throughout the body and the hair follicles.

What does this have to do with hair loss?

Well, studies have shown that variations in the AR gene can result in increased activity of the androgen receptors in the hair follicles. One variation that has been linked to increased activity is a heightened sensitivity to DHT, essentially meaning being more prone to the damage that DHT can cause to your hair.

The AR gene is located on the X chromosome, which men always inherit from their mother. So that means that it should be easy to trace and predict the baldness gene, just look at the mothers X chromosome, right? Wrong.

Genetics are more complicated than that

There is a myth that has become commonplace in the hair loss community: you always look to your mother’s side of the family to determine whether or not you will go bald.

In retrospect, this idea makes sense given that the AR gene is located on the X chromosome. The idea tends to “stick” because so far AR is the only gene that scientists have been able to confirm plays a role in androgenic alopecia, but there is strong evidence that other genes play a role too.

Gene tests also play a role in feeding that myth. According to one study, gene tests can test the AR gene variations and predict with 70% accuracy whether or not male androgenic alopecia will develop.

But genetics are more complicated than that.

Just because one gene has been proven to play a role in androgenic alopecia does not mean that others don’t as well. In fact, the truth is that there are likely many more factors, most of which scientists do not understand, that play a role in the development of AA.

You see, hair loss genetics is a relatively new field and there are more and more discoveries being made daily. Scientists just recently discovered that there are many DNA variants that are located in or near the genes that are involved in the process of creating hair. This has many implications that go against the notion that hair loss only comes from your moms side.

In fact, it may come from your dad’s side as well. Multiple studies (1,2) that have looked at other genes apart from the AR gene, and found strong implications for baldness triggers on the Y chromosome (inherited from the father) as well. This makes sense because what has been found in family studies, as well if you just generally pay attention, is that there is often a strong resemblance in the pattern of hair loss between fathers and sons, which cannot be explained by the AR gene.

In conclusion, which one of my family members can I blame for my hair loss?

The truth is you can’t blame anyone for certain, it could be your mom or your dad.

Though there is some merit to the claim that the AR gene from your mothers X chromosome can predict your hair loss, it cannot predict it entirely and there is likely a lot more to the equation.

Since the field of genetics and hair loss is still relatively new, there is still much to be discovered. It seems that the further scientists delve into the field, the more confusing things become, and the closer we move to determining that hair loss can come from a variety of genes and gene variations from both your mothers and your fathers side of the family.

Lucky for us research will get better and better. What you should not do is let the results from a DNA test or having a bald grandpa cause you to worry about it. The best thing that you can do is to loosely pay attention to research in the field and cross your fingers that it doesn’t happen to you. If you do start to see symptoms, talk to your doctor and take action right away, the quicker you act the more hair you will save in the end.