How is baldness inherited ?

[Ventures]

There are lot of theories how exactly male pattern baldness is inherited. As far we can understand male pattern baldness is multifactorial and polygenic trait and it’s complicated to predict aggressiveness, pattern and when it will start . But regarding discoveries and analysis I think we can point up this two critical factors resulting in onset of baldness in individual.

1. The amount of 5-alpha-reductase ( which is required for conversion of T to more potent DHT ) in the scalp and other tissues – This is usually inherited from father, or other relatives (uncle etc.)
2. AR sensitivity of hair follicles to DHT and other androgens – This is always inherited from your maternal grandfather.

Baldness is a result of how much DHT is produced in your organism and in the same time how your hair follicles are sensitive. First you inherit mostly from your father and second from your maternal grandfather because the gene which is responsible for encoding the AR is located on the X chromosome (Wiki: In humans, the androgen receptor is encoded by the AR gene located on the X chromosome at Xq11-12.) . Both contribute to baldness.

It’s quite challenging to predict baldness. A brief report regarding my own family. Father has all the hair on his head , the hairline as a teenager , but has a prostate problem (BPH) which is also a result of increased levels of DHT. He is on Proscar (5 mg finasteride), and although all his life he had obviously increased levels of DHT, he haven’t lost any hair on his head because he inherited good genes from his mother’s side of family. Grandfather ( mother's side ) has hairline appropriate for his age. And obviously I have problem with hair loss, as I am member of this internet community forum. I obviously inherited the amount of hormones in the body from my father and level of AR sensitivity from maternal grandfather.
Fact that your grandfather has hair does not mean a lot, and doesn’t ensure you will be spared from male pattern baldness. You should check levels of androgens during his life. Some people have low levels of free T and other androgens including DHT all their life, and of course that doesn’t prove whether or not or not you have sensitive follicles.


I would like to hear comments of other posters how this model of inheritance is accurate or not. Maybe you can mention your own family history. Can we inherit a pattern that resembles more to your father then maternal grandfather ? Or distribution of AR in your scalp which results in pattern is directly linked to your grandfather. For instance, if your grandfather lost his hair only on vertex but not in frontal region, that means you will likely follow the same pattern ?

 

[GoldenMane]

Sounds very plausible, apart from inheriting 5 alpha reductase gene from an uncle of course!

Makes sense in my case, having a maternal grandfather who was NW4 in his early 20s and my father who has been receeding from the front at a much slower rate, now in his 40s he's approaching that island thing at the front, but his vertex is fine. Both me and bmy brother started losing our hair in our 20s, for me it's only become noticable at age 27, for my brother it became noticable at about 22 or 23, but he got on finasteride at about 24 and recovered remarkably well (not perfect, but very good). I myself was diffuse thinning and had some temporal recession (NW2) the diffuse thinning has completely recovered in 3-4 months, but the temples, while thickening to normal density, have not moved a millimeter!

But this also means that people with low alpha 5 reductase activity who are experiencing hairloss are particularly screwed, we can inhibit 5 alpha reductase, but we can't inhibit the receptor sites on the follicles yet as far as I'm aware. If there was some way to inhibit the actual follicle binding site for DHT then it would help low Testosterone people an dwork in tandem with finasteride for even better results in the rest of us.

 

[Ventures]

And one interesting fact I noticed is there are lot of people here from nothern countries (ireland, norway, sweeden, even germany, denmark or so ). It seems these people inherited very sensitive receptors, given that lab test usually show they have normal DHT levels, and they don't have body hair or other tipical signs of elevated androgen levels. That certainly shows that some nations and phenotypes (ginger and blue hair - In the same time I know male pattern baldness genes are not directly linked to hair color or texture) are more prone to onset of male pattern baldness regarding their genetic pool.

 

[GoldenMane]

I wouldn't put too much pass on that. It's not just Northern Europeans, baldness is very common among people of african descent, middle eastern Arabs, Israel has a very high frequency of baldness, and most Israelis are descended from Russian and Polish immigrants. I think it may be less common among asian and native american people, Spanish too, but anecdotally I've seen a lot of balding Itallians, though it tends to hit them more at middle age than in their 20s. I'm sure the prevalence of follicle sensitivity and 5 alpha reductase production does vary by region and ethnicity, probably northern Europeans , Arabs and African descent people do have a higher frequency of these alleles in their populations though.

 

[Ventures]

Yes, I am aware of fact that that it may vary by region and ethnicity but I've read a lot of threads of young guys from northern countries who started balding in their early 20s. Of course, there are lot of french guys here, and italians and spanish. But It seems to me that nothern people who have trouble with male pattern baldness often develop sparse or reduced body hair which would sugest they allready have low T and DHT levels and would support fact that these poeple do have a higher frequency of significant alleles in their AR gene.

What procent of males in your country @goldenmane have significant body hair and don't have male pattern baldness ?

 

[GoldenMane]

You studied genetics too Ventures?

Hmm that's quite difficult to say, being a cold country people wear a lot of clothes so it's hard to gauge the hairiness of the average man! Again, anecdotally, most men here do tend to have significant hairloss in their 40s and 50s, but hairloss in a man's 20s isn't super common.

Speaking for myself, my maternal grandfather who went bald in his 20s is quite hairy, but me, my brother and my dad are not. Oddly, I've noticed an increased hairness in myself since starting on the big three. My eyebrows are growing thicker and darker, my arm hair is too, and I'm starting to see hair growth between my eyebrows and temples too, so whatever finasteride (assuming it is working and minoxidil is not the sole cause of my recovery) is doing, it seems to be promoting body hair growth as well as hair growth. It's possible that increased body hair is due to higher systemic testosterone now that alpha 5 reductase is being inhibited...

Again, anecdotally, whenever I've been in France, I have noticed a very small proportion of young males with hairloss.

One theory is that in northern males, due to decreased sunlight, hairloss alleles became fixed in the populations because the exposed scalp allows for greater sun exposure and vitamin D production, but that doesn't explain the high prevalence in people of arab and african descent.

 

[TheHandsomeLurker]

A good start, but you don't always inherit your maternal grandfather's AR gene.

The AR gene is located on the X chromosome; your mother gets one from her father and one from her mother, so which one you get is a 50/50 shot.

As far as inheritance, we haven't fully worked that out yet. There are plenty of studies implicating maternal inheritance, but there are other genes which have been considered to put one at risk for androgenic alopecia (one is on chromosome 10, but that's basically all I remember).

 

[maher]

Baldness is not inherited, predisposition to balding is. Interesting study:

http://www.jle.com/e-docs/00/01/88/AE/article.phtml

"Almost all men who developed balding before the age of 30 had a balding father"

 

[TheHandsomeLurker]

Baldness is not inherited, predisposition to balding is. Interesting study:

http://www.jle.com/e-docs/00/01/88/AE/article.phtml

"Almost all men who developed balding before the age of 30 had a balding father"

Technically correct. The castrati of old didn't go bald because they didn't produce enough testosterone. Furthermore, a woman can have a lot of the associated genes and not go bald because her body doesn't produce testosterone in sufficient quantities (which would then be converted to DHT in sufficient quantities to bind to the androgen receptors on hair follicles).

I've seen studies that found men with balding fathers are 2.5 times more likely to go bald. However, that's not necessarily due to genetic inheritance from the father. It could be the case that women with the genes associated with androgenic alopecia are much more likely to reproduce with balding men.

 

[Ventures]

A good start, but you don't always inherit your maternal grandfather's AR gene.

The AR gene is located on the X chromosome; your mother gets one from her father and one from her mother, so which one you get is a 50/50 shot.

As far as inheritance, we haven't fully worked that out yet. There are plenty of studies implicating maternal inheritance, but there are other genes which have been considered to put one at risk for androgenic alopecia (one is on chromosome 10, but that's basically all I remember).

Yes I understand that, but why people tend to say that AR gene is directly inherited from your maternal grandfather ? Maybe your mom passes you X chromosome from her male parent not female ?

 

[TheHandsomeLurker]

Yes I understand that, but why people tend to say that AR gene is directly inherited from your maternal grandfather ? Maybe your mom passes you X chromosome from her male parent not female ?

Lol no, but I think I understand the error here. You're interpreting a predictor for a condition as if it meant you always get the condition. Or at the very least, you heard this from someone who misinterpreted it.

A lot of people say that your mother's father or brother can be good predictors of going bald, because that's true: if your mother's father is bald, that means it is very likely he has an X chromosome with the problematic AR gene, and if that is the case, then at least one of your mother's X chromosomes has the gene, ie you have at least a 50/50 chance that you will get the gene (which, as noted, predisposes you to androgenic alopecia -- it does not ensure you will go bald).

(And similarly with your mother's brother, his baldness would indicate a high likelihood that he has the bad AR gene, meaning that it's likely your mother has it, too, whether or not your mother's brother gets this gene from his father or his mother).

Some people mistake this indicator for saying something much stronger than it does. Baldness does not imply a bad AR gene in all cases, although it does seem to coincide with the vast majority of them. And even if we incorrectly assume that baldness always implies a bad AR gene, having a bald maternal grandfather only tells you about one of your mother's two X chromosomes. You could get lucky and get the good one, if there is one.

Does that make sense?

 

[Ventures]

Yes, this is perfectly clear... Mom's brother inherited X chromosome from his mother, not his father (your maternal grandfather ). So, let's imagine you have bald mom's brother and bald maternal grandfather -- in that scenario you are not lucky at all. Which means it doesn't matter which X you inherit, both have AR receptor alleles which cause baldness. But if your grandfather is only bald male on your mother side of family then you have 50/50 to inherit "good" X chromosome.

My second question is does AR gene also contribute to body hair. I mean, AR gene encodes sensitivity of all androgen receptors in cells and tisues. Therefore I would assume that same gene is important how your body hair reacts to androgen stimulus ?

And I want to distinguish number of androgen receptors (Num. of AR follicles posses) and sensitity of individaul AR. A this it’s crucial to point up this to parameters. AR gene (Xq 11-12) encodes sensitivity of individual androgen receptor. But I assume other genes determine how many of them are located in scalp follicles, body hair follicles and so on.
t his father (your maternal grandfather ). So, let's imagine you have bald mom's brother and bald maternal grandfather -- in that scenario you are not lucky at all. Which means it doesn't metter which X you inherit, both have AR receptor alleles which cause baldness. But if your grandfather is only bald male on your mother side of family then you have 50/50 to inherit "good" X chromosome.

My second question is does AR gene also contribute to body hair. I mean, AR gene encodes sensitivity of all androgen receptors in cells and tisues. Therefore I would assume that same gene is important how your body hair reacts to androgen stimulus ?

And I want to distinguish number of androgen receptors (Num. of AR follicles posses) and sensitity of individaul AR. A this it's crucial to point up this to paramaters. AR gene (Xq 11-12) encodes sensitivity of individual androgen receptor. But I assume other genes determine how many of them are located in scalp follicles, body hair follicles and so on.So in my opinion, as some scientist, researchers mentioned in their papers.

Term how sensitive hair follicle is to androgens covers both number of androgen receptors (No. of AR) and sensitivity of each receptor (AR sens.). This leads us to important equation:

Sensitivity_of_HairFollicle = (Num. of AR) x (Sensitivity of each AR);
​

What gene does determine how many AR there will be ?

 

[abcdefg]

You raise some questions, but you might be getting ahead of the science. Its not like male pattern baldness is all charted out in some book somewhere lots of questions are just not known right now. I completely agree about the importance of sensitivity and receptors that is very often overlooked. CB 03 01 and future treatments do target the receptors so hopefully that avenue is safer and more efficient that the current treatments
I doubt all the genes for receptors are all mapped out yet and its probably more complicated then we like to think. Could be combinations of genes along with hormone triggers or who knows what

 

[TheHandsomeLurker]

Yes, this is perfectly clear... Mom's brother inherited X chromosome from his mother, not his father (your maternal grandfather ). So, let's imagine you have bald mom's brother and bald maternal grandfather -- in that scenario you are not lucky at all. Which means it doesn't matter which X you inherit, both have AR receptor alleles which cause baldness. But if your grandfather is only bald male on your mother side of family then you have 50/50 to inherit "good" X chromosome.

My second question is does AR gene also contribute to body hair. I mean, AR gene encodes sensitivity of all androgen receptors in cells and tisues. Therefore I would assume that same gene is important how your body hair reacts to androgen stimulus ?

And I want to distinguish number of androgen receptors (Num. of AR follicles posses) and sensitity of individaul AR. A this it’s crucial to point up this to parameters. AR gene (Xq 11-12) encodes sensitivity of individual androgen receptor. But I assume other genes determine how many of them are located in scalp follicles, body hair follicles and so on.
t his father (your maternal grandfather ). So, let's imagine you have bald mom's brother and bald maternal grandfather -- in that scenario you are not lucky at all. Which means it doesn't metter which X you inherit, both have AR receptor alleles which cause baldness. But if your grandfather is only bald male on your mother side of family then you have 50/50 to inherit "good" X chromosome.

My second question is does AR gene also contribute to body hair. I mean, AR gene encodes sensitivity of all androgen receptors in cells and tisues. Therefore I would assume that same gene is important how your body hair reacts to androgen stimulus ?

And I want to distinguish number of androgen receptors (Num. of AR follicles posses) and sensitity of individaul AR. A this it's crucial to point up this to paramaters. AR gene (Xq 11-12) encodes sensitivity of individual androgen receptor. But I assume other genes determine how many of them are located in scalp follicles, body hair follicles and so on.So in my opinion, as some scientist, researchers mentioned in their papers.

Term how sensitive hair follicle is to androgens covers both number of androgen receptors (No. of AR) and sensitivity of each receptor (AR sens.). This leads us to important equation:

Sensitivity_of_HairFollicle = (Num. of AR) x (Sensitivity of each AR);
​

What gene does determine how many AR there will be ?

Almost correct, except every time you note a 50% chance, you should note at least a 50% chance since we're only looking at phenotype. The caveat is that the AR gene on the X chromosome isn't the only gene involved in male pattern baldness. We don't have any findings to suggest that getting an AR allele which coincides with androgenic alopecia will always lead to androgenic alopecia.

But let's examine a case in which the maternal uncle and grandfather are bald, and let's simplify to say that in men the AR gene on the X always leads to male pattern baldness. From the family data, we know the mother received one bad AR gene from her father, and that the maternal grandmother has at least one AR allele for male pattern baldness. That means there's at least 75% chance that you will inherit the male pattern baldness AR allele. But we can't conclude that bald uncle + bald grandpa = bald you.

As for precisely how the AR gene affects body hair and the other genes involved there, well that's beyond my knowledge, but I would assume it's a complex system, ie male pattern baldness and hirsuteness don't necessarily coincide.

 

[Ventures]

So, looking at Prince William and his brother Harry, we can assume Harry got "good" or at least better X chromose gene regarding he doesn' t have bald patch on head as his few years older brother ? (We can exclude he uses propecia or other topicals...)

 

[Ventures]

According to articles AR located on X chromosome plays huge role. http://www.sciencedaily.com/releases/2005/05/050520172151.htm
Of course there are other genes involved in male pattern baldness Gene on chromosome 20. 5ard gene and else.

Why people from northern Europe more tend to have certain alleles which leads to AR sensitivity ?

 

[Fena2000]

This is really interesting. Does it work the same for women? My maternal grandfather had a head full of thick hair, my maternal grandmother had thinning hair later in life, but I think it was more age related, my father is bald. So where did I get the bad gene from? Still can't figure it out.

 

[SayifDoit]

This is really interesting. Does it work the same for women? My maternal grandfather had a head full of thick hair, my maternal grandmother had thinning hair later in life, but I think it was more age related, my father is bald. So where did I get the bad gene from? Still can't figure it out.

From your dad lol!

People who honestly believe you don't inherit baldness from your dad are living in a dream world. I have seen countless guys (including myself) on these forums who've inherited the baldness gene from their dad, some even resent them for it lol!

 

[Fena2000]

From your dad lol!

People who honestly believe you don't inherit baldness from your dad are living in a dream world. I have seen countless guys (including myself) on these forums who've inherited the baldness gene from their dad, some even resent them for it lol!

Women too? Why am I the only lucky one to inherit this from my dad and I know soooo many women with balding dads who don't . Then again, I guess guys can say the same.
I don't resent my parents for it, but I'm very disappointed in the mental support I get. All I hear is , just get over it and move on. Wish it was that easy.

I think I inherited the AR receptor from my dad and the amount of DHT from my moms side. My maternal grandfather had a head full of hair, but he died from prostate cancer, so he must have had a lot of DHT but wasn't sensitive to it. On my dads side , almost all uncles are bald and dealt with acne and SD problems, which I think is the result of sensitive AR receptors. So I think it also works the opposite way.

 

[brent777]

I can't figure out how my older brother kept all his hair but I started losing mine in early 30s