Lycanthropy
Lycanthropy,
in Mythology werewolves are entities that are human, but
shape shift
into animal form during certain lunar aspects which affect
their DNA.

Under
Lycanthropia, Burton notes as follows in his Anatomy
of Melancholy: "Lycanthropia, which Avicenna calls Cucubuth,
others Lupinam Insaniam or Wolf-Madness, when men run howling
about graves and fields in the night, and will not be persuaded
but that they are wolves or some such beasts. Aetius and
Paulus call it a kind of melancholy; but I should rather
refer to it as madness, as most do. This malady is nowadays
frequent in Bohemia and Hungary. Schernitzius will have
it common in Livonia. They lie hid most part all day, and
go abroad in the night, barking, howling , at graves and
deserts; they have usually hollow eyes, scabbed legs and
thighs, unquenchable thirst and are very dry and pale."

From:
Montague Summers, His Kith and Kin (1928): A
Guide to Vampires

Dictionary
Definitions
- (In
folklore and superstition) a human being that has changed
or been changed into a wolf, or is capable of assuming
the form of a wolf, while retaining human intelligence.
- Lycanthropy:
Lycanthropy from Greek lykoi, "wolf" anthropos, "man"
- a delusion that one has become a wolf. The assumption
of the form and characteristics of a wolf held to be possible
by witchcraft or magic
At
the Center of Biomedical Research in Guadalajara, Mexico
geneticist Dr. Luis Figuera is studying a Mexican family
(the Aceves) with a rare genetic mutation, that causes fur
like hair to grow all over their bodies. This werewolf disorder
has mysterious resurfaced for the first time since the middle
ages. The gene that causes the mutation has been dormant
for centuries. It can be passed through either parent in
the "X" chromosome. This is known as the "Werewolf Disorder".
In
the Aceves family... all 32 member have this disease. They
live in a mountain town named Zacatecas in Mexico. The hair
covers much of their body... even in females. Some members
of the family have more hair than others. One of them performs
as a wolfman in a traveling circus.
Dr.
Figuera may not be able to cure their affliction but he
is hoping to isolate the gene and help others. He is also
hoping, because of his studies, to help people with hair
loss.

from:
http://www.crystalinks.com/werewolves.html