deCODE Complete

Male pattern baldness is in part, a genetically determined condition.

deCODEhealth analyzes your patients’ DNA and provides male customers of European descent with a personalized interpretation of their genetic risk for developing male pattern baldness.

At present, the necessary scientific information to interpret the genetic risk of hair loss in women or individuals of other ethnicities is not available for the genetic variants known to associate with male pattern baldness.

Male pattern baldness is usually inherited – deCODEhealth can help you find a genetic predisposition to this most common form of hair loss in men

Male pattern baldness is caused by a combination of hormones and genetics

Male pattern baldness is the most common form of hair loss in men and women. Doctors refer to this common cause of baldness as androgenic alopecia, an inherited sensitivity to the effects of androgens (male hormones) on scalp hair follicles which causes them to shrink and prevents them from producing hair normally.

Male pattern baldness causes hair loss in a well-defined pattern

Men affected by this condition lose their hair in a well-defined pattern, beginning above both temples. Over time, the hairline may either recede uniformly from the forehead (referred to here as frontal hair loss) or more commonly to form a characteristic "M" shape (referred to here as vertex hair loss) which also associates with hair loss at the crown of the head. Both patterns of hair loss often progress to partial baldness (forming a horseshoe pattern of hair around the sides of the head) or in some to complete baldness.

(Figure adapted from the Hamilton and Norwood scale, see Hamilton J.B. (1951))

Women can also develop this type of baldness. The pattern of female pattern baldness, however, tends to be different from men’s. Typically, women will notice diffuse hair loss throughout the mid scalp but retain the majority of their hairline.

Male pattern baldness is most common among men of European ancestry

Some degree of male pattern baldness affects roughly 50 percent of males of European descent during their lifetime. The proportion of affected males increases steadily with age. The incidence and the effects of male pattern baldness tend to be greatest in men of European ancestry, second highest in Asians and African Americans, and lowest in Native Americans and Eskimos.

A genetic variant on the X chromosome associates with male pattern baldness

Male pattern baldness is, in part, a genetically determined condition, associated with a genetic variant in the Androgen Receptor (AR) gene on the X chromosome, one of the so-called sex-chromosomes. Males have one X chromosome and one Y chromosome whereas females have two X chromosomes. Since sons always inherit their X chromosome from their mothers, the genetic variant in the AR gene associated with male pattern baldness is inherited maternally. Recently, scientists have discovered a second variant, on chromosome 20, which also associates with male pattern baldness. Most genetic studies define male-pattern baldness as the hair loss depicted as stages 5, 6 and 7 in the schematic figure above.

deCODEhealth analyzes your patients’ DNA and interprets their risk of male pattern baldness

The deCODE Complete Scan identifies the variants referred to above and uses them to provide male customers of European descent with a personalized interpretation of their genetic risk for developing male pattern baldness.

At present, the necessary scientific information to interpret the genetic risk of hair loss in women or individuals of other ethnicities is not available for these variants. This information will be added as soon as it becomes available and we are assured of its quality.

Risk factors for male pattern baldness

A variety of genetic and environmental factors are thought to play a role in the development of male pattern baldness. Some of these are listed below, but researchers suspect that many factors remain undiscovered:

• Gender: Male pattern baldness affects both men and women, but is a more frequent cause of hair loss in men. Male pattern baldness affects an estimated 35 million men in the United States.
• Age: More than 50 percent of men over the age of 50 have some degree of hair loss. Male pattern baldness in men can start as early as in the teens and risk increases with age. In women, hair loss due to androgenic alopecia is most likely after menopause.
• Family history: Male pattern baldness tends to cluster in families and having a close relative with patterned hair loss appears to be a risk factor for developing the condition.
• Genetics: Since sons always inherit their X chromosome from their mothers, the AR genetic variant is inherited maternally. Sons however also seem to take after their fathers when it comes to hair loss, so researchers suspect that several other genes inherited from both parents play a role. The recently found variant on chromosome 20, which also associates with male pattern baldness, supports this.

Treatments are available to slow the hair-thinning process

Male pattern baldness does not indicate a medical disorder. There is no known prevention for male pattern baldness and treatment is not necessary, unless people are uncomfortable with their appearance. Hair weaving, hairpieces, or change of hairstyle may disguise the hair loss. This is usually the least expensive and safest approach for hair-thinning and baldness. Hair loss is usually permanent, but there are medications available that can slow the hair-thinning process:

• Minoxidil – a solution applied directly to the scalp to stimulate the hair follicles and slow hair loss. It is most effective for people under 40 years of age whose hair loss is recent and has no effect on receding hairlines. The previous degree of hair loss returns when applications are stopped. Minoxidil is the only medication approved for hair loss in women.
• Finasteride – a prescription pill that is used alone or in combination with other medications to treat benign enlargement of the male prostate gland. Like minoxidil, the results are more likely to be slower hair loss than actual new hair growth. The previous degree of hair loss returns when people stop taking the drug.

More information about male pattern baldness

You can find out more information about male pattern baldness by talking to your doctor and visiting these Web sites:

• American Academy of Dermatology on hair-loss and baldness
• Medline Plus article on Male Pattern Baldness
• Medline Plus article on Female Pattern Baldness
• DermNet New Zealand article on Male Pattern Baldness

Scientific references

1. Ellis, J.A., Scurrah, K.J., Cobb, J.E., Zaloumis, S.G., Duncan, A.E., & Harrap, S.B. (2007). Baldness and the androgen receptor: the AR polyglycine repeat polymorphism does not confer susceptibility to androgenetic alopecia.Human Genetics, 121 (3-4), 451-457.
2. Ellis, J.A., Stebbing, M., & Harrap, S.B. (2001). Polymorphism of the androgen receptor gene is associated with male pattern baldness.Journal of Investigative Dermatology, 116 (3), 452-455.
3. Hamilton J.B. (1951). Patterned loss of hair in man; types and incidence.Annals of the New York Academy of Sciences, 53 (3), 708-28.
4. Hillmer, A.M., Hanneken, S., Ritzmann, S. et al. (2005). Genetic variation in the human androgen receptor gene is the major determinant of common early-onset androgenetic alopecia.American Journal of Human Genetics, 77 (1), 140-148.
5. Hillmer, A.M., Brockschmidt, F.F., Hanneken, S. et al. (2008). Susceptibility variants for male-pattern baldness on chromosome 20p11.Nature Genetics, 40 (11), 1279-1281.
6. Norwood, O.T. (1975). Male pattern baldness: classification and incidence.Southern Medical Journal, 68 (11),1359-1365.
7. Richards J.B., Yuan X., Geller F. et al. (2008). Male-pattern baldness susceptibility locus at 20p11.Nature Genetics, 40 (11), 1282-1284.

This content was last reviewed on March 02, 2011.