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Up to 80 percent of the population has some degree of hair loss,
and each year more than $7 billion is spent on treatments and cures
for the problem.
The hair growth cycle is influenced by a number of factors, including
genetics, age and lifestyle, though genetics is responsible for
95 percent of hair loss cases.
There are many different types and causes of baldness, also called
alopecia. For example, patchy hair loss (alopecia areata), loss
of all hair on the head (alopecia totalis), and loss of all hair
on the body (alopecia universalis) are autoimmune disorders in which
the hair follicles are mistakenly attacked by the body’s immune
system.
Other factors can also cause hair loss including:
- Nutritional deficiencies such as too little protein, iron or
zinc in the diet
- Emotional stress
- Pregnancy or other hormonal shifts
- Medications such as chemotherapy drugs
- Tying hair too tightly, such as in corn rows
While drugs such as Propecia, which was originally used for prostate
cancer and helps prevent thinning hair, and Minoxidil (Rogaine),
which stimulates hair growth, can aid in hair loss problems, researchers
have discovered a "hairless" gene that may lead to a more
thorough understanding of the hair growth cycle and the development
of more effective treatments.
Androgenetic alopecia, a genetic condition known as male pattern
baldness, affects more than 50 percent of men over 50 years of age,
along with about 20 percent of women in the same age group. In this
condition, hair is often lost from the crown of the skull and the
temples.
According to researchers, pattern baldness appears to be more complicated
than one gene, and is thought to be influenced by the male hormone,
dihydrotestosterone, or DHT. Individuals with this type of hair
loss have a higher number of DHT receptors in the areas where they
are losing their hair. Researchers are uncertain how DHT works to
damage hair follicles. Gene therapy may also be used to treat hair
loss, along with graying hair, in the future. Researchers have been
able to modify the genes in mouse hair follicles to grow hair and
have been able to graft the modified skin onto hairless mice.
The technology would first be used to treat hair loss caused by
chemotherapy but later could be applied to androgenic alopecia and
other conditions.
Boston
Globe March 25, 2003
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