Red_Dave said:
does anyone have/know a good source for any information the genetics of balding? Its something ive been trying to work out recently as most men on my fathers side of the family have gone bald. Ild assumed I wouldnt go bald as most people say that my hairs similar to the hair on my mums side of the family rather than my dads and no one on my mums side of the family has gone bald. For example the blokes on my dads side of the family tended to go blonde during the summer due to the heat buts thats never happend to me so i assumed i wouldnt go bald. Was i right in doing this or should i start worrying?
There is no link that discusses it in detail so I will provide a synopsis.
First of all , male pattern baldness, the most common cause of nonscarring alopecia (baldness) is inherited in a
polygenic fashion. or a trait inherited by either or both of the parents. It may be a sex limited due to incomplete expression and penetrance but not X linked inheritance like color blindness. Male pattern baldness is a classic example of how inheritance pattern for something as simple as balding cannot be explained by pure Mendelian genetics anymore. It can be inherited in a autosomal dominant manner but we now know it is inherited from both parents and can have
incomplete penetrance thus, have varying levels of expression in the person who carries the gene.
Ie: you can have the gene, but you don't go bald or you can look like Yul Brenner!
The hormonal environment has to be right therefore, men express it early due to high levels of testosterone and byproduct hormones. Women can express it early if they have untreated congential adrenal hyperplasia (where the adrenal glands overproduce male hormones) and carry the gene or a ovarian tumor that produces testosterone. The latter women are lucky to have the balding gene, since this is how the docs find out a young woman has an ovarian cancer (she startes balding at 30). The hormonal mileu of the women approaches that of men after menapause (higher ratio of testosterone to estrogen) (Remember, our adrenal glands continue to make testosterone until death) so some women who carry the gene will start expressing it then. Also overactive or underactive thyroid can cause hair loss.
Intersting there is a racial preferrance. Androgenic alopecia is responsible for male pattern baldness in fifty percent of white men and women over 40 but less so in blacks and Asians, thus the
coinheritance (say a racial gene inherited with the balding gene ) may also be important.
Some people may not have the gene and still have age related miniaturization of the hair follicles and it can look like incomplete balding. These people probably won't respond to Propecia (a 5-alpha reducatse inhibitor) but might respond to Rogaine (don't really know the mechanism of action of the latter).
Rember, there are other causes of "cue ball" like non scarring alopecia called alopecia areata, alopecia totalis etc. which are not genetic disorders so much as autoimmune conditions (like Lupus, Rheumatoid etc.)
Most of all, remember, we have yet to isolate the specific gene or set of genes exclusively responsible for male pattern baldness!!!!
Interesting, that some women exhibit the female pattern hair loss (diffusse thinning ) and some the M shaped male pattern of (early loss in temporal area etc.) Female pattern hair loss may be a different mechanism and responds to estrogen and or Rogaine but not to Propecia unlike male pattern hair loss where you can use the Propecia in these women. In addtion, it may be that women have the 5-HT enzyme expressed in a diffuse manner rahter than concentrated in the M distribution on the men. I would have to look into that.
If guys want to minimize their chance of going bald, you can get castrated (thus stopping the major source of testosterone production) but don't forget, you have to rip out your adrenal glands too.:mrgreen: