Scientists may have tapped into a potential Fountain of Youth
after discovering that gene therapy can restore hair color and
can temporarily get rid of the gray.
While such treatment may be years away, Dr George Cotsarelis
and colleagues in Philadelphia have found that repairing genes
in the follicles of albino mice effectively produced colored
Gray hair is caused by the loss of color-producing cells called
melanocytes, which occurs naturally during aging. Scientists
at Thomas Jefferson University and Jefferson Medical College
and at the University of Pennsylvania, in Philadelphia, either
injected a gene into the skin of fifteen mice or used a topical
Within a few weeks, a small number of colored hairs grew at
the treatment site. But the color only lasted about three months.
Researchers say determining how to correctly repeat the gene
mutation responsible for producing hair pigment could provide
more lasting color effects.
"Gene therapy has just taken a cosmetic step forward,"
Robert M. Hoffman, president of the San Diego, California based
company AntiCancer Inc., wrote in an editorial accompanying
the study. Both articles appear in the January issue of Nature
Albino mice have white hair but this is not the same as having
hair go white due to age. Albino mice, like albino humans, have
a genetic defect that stops the production of melanin pigment.
It is important to note that albinism in all these mice is due
to a specific defect in the tyrosinase gene (Tyr) resulting
from a homozygous c/c allele presence. These defective alleles
result in an inability to convert a molecular substrate to the
ultimate melanin pigment product. The inability of albino mice
to produce pigment stems not from an absence of melanocytes
and/or melanocyte activity, but from a deficiency or alteration
of the tyrosinase structure in melanocytes that are otherwise
normal. What the researchers did was to replace the defective
tyrosinase c alleles with normal C alleles making the gene functional
Albino mice do have melanocytes in their hair follicles but they
are amelanotic, whereas hairs that are white due to age have a
reduced number of, or no, melanocytes present in the hair follicles.
So this gene therapy by Dr. George Cotsarelis and company is not
so much a treatment for white hair, but is a demonstration that
defective genes in hair follicles can be replaced using gene therapy.