Baldness is a general term that describes unwanted hair loss. When the condition stems from genetic inheritance, it is called androgenetic alopecia. At one time, scientists believed that inherited baldness came from one particular side of your family tree. They now believe that you can inherit baldness from either side of your family.
Inherited Hair Loss Basics
Androgenetic alopecia is also known as male or female pattern baldness. In men, the condition causes a loss of the front hairline and the eventual development of a horseshoe-shaped pattern in the remaining hair on the scalp. If you have female pattern baldness, you typically will not lose your front hairline. Rather, you will experience a thinning of hair that begins at the crown of your head and eventually progresses throughout your scalp. Unlike men, women with inherited baldness do not usually go completely bald.
The AR Gene
Inherited baldness is substantially determined by the actions of a gene called the AR gene, according to U.S. National Library of Medicine's Genetics Home Reference. This gene helps determine how your hair follicles respond to the presence of a hormone called dihydrotestosterone, or DHT. Your body creates DHT in your scalp when the male hormone testosterone -- which is found in both men and women -- interacts with an enzyme called Type 2 5-alpha reductase, the American Hair Loss Association reports. Once formed, DHT alters the size of your hair follicles and decreases the viability of your hair strands. Individuals with certain changes in their AR genes have an increased susceptibility to DHT's damaging effects.
Both men and women can inherit DHT sensitivity from either side of their family, according to the New Zealand Dermatological Society. In addition to the AR gene, any number of other genetic factors may affect the way that baldness is expressed on your scalp. While men typically experience inherited baldness when they have significant elevations in their levels of DHT, women can develop hair loss even when their testosterone and DHT levels fall within normal parameters.
A number of environmental or hormonal factors may affect the real-world expression of inherited hair loss, Genetics Home Reference reports. If you are male, genetic baldness may also have an association with increased risks for prostate cancer or coronary artery disease. Genetic hair loss in women may have an association with increased risks for the development of polycystic ovary syndrome, or PCOS. Scientists do not know precisely how the AR gene or other genetic, environmental or hormonal factors trigger hair loss.
In addition to genetic and hormonal factors, female hair loss is also associated with advancing age, Medline Plus reports. Men can address genetic hair loss with the medications minoxidil, which stimulates the hair follicles, and finasteride, which limits DHT production. If you have female genetic hair loss, the only approved treatment for your condition is minoxidil. In some cases, your doctor may also prescribe an unapproved medication called spironolactone. Consult your doctor for more information on inherited hair loss.
- Genetics Home Reference -- U.S. National Library of Medicine: Androgenetic Alopecia
- The New Zealand Dermatological Society: Male Pattern Hair Loss
- The New Zealand Dermatological Society: Female Pattern Hair Loss
- Medline Plus: Male Pattern Baldness
- Medline Plus: Female Pattern Baldness
- American Hair Loss Association: Women's Hair Loss; Causes of Hair Loss