Hair Loss and Androgenic Alopecia

By Matthew James

Androgenic Alopecia is also known as male pattern baldness,hereditary balding, and androgenetic alopecia. It is the most common form of hair loss. It has a higher incidence in men than in women mainly due to sex hormones.

Androgenic Alopecia is described as thinning of the hair on the scalp as opposed to follicular hair loss. Male pattern hair loss usually doesn't present itself until after puberty when the male hormones are elevated. This is when someone with a genetic predisposition to balding will start to notice their hair thinning. Studies have shown that around half of all caucasian men over the age of 40 experience some form of hair loss. The occurence and severity in other cultures seems to be much lower, but still present.

Androgens, specifically testosterone and dihydrotestosterone or DHT, are necessary to activate the genes in the scalp to create hair loss.Genes are able to modify the way the scalp responds to circulating androgens in the blood.

Three key features of alopecia include: Follicular miniaturization. Hair follicles are full of androgen receptors and when androgens are present, genes that shorten the anagen phase are activated. Then the follicles may shrink or become miniaturized. Eventually the follicles shrink and nonpigmented vellus hairs replace pigmented terminal hairs. Males with alopecia have a reduction in terminal to vellus hair ratio and exhibit typical distribuion of hair loss. Areas of inflammation. It is widely believed that a variety of genetic and environmental factors contribute to androgenic alopecia. Even though researchers are hard at work studying the many possibilities, most of these remain unknown. Many scientists point to the maternal side of the equation for the link to the balding gene, but there seems to be conflicting evidence. There are other genes found to be involved with hair loss as well. In 2009, Japanese researchers identified a gene called Sox21, which they say is responsible for hair loss in people.

Scientists are just beginning to discover the complex map of the human genome. DNA is an enormous puzzle that will take decades, so evidence of the gene or genes responsible for hair loss won't be completely evident for many years to come. - 30305

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