Webster's New World Medical Dictionary

eyes, spots in front of the
The spontaneous
appearance of spots in the eyes. Also known as
“floaters,” spots are usually images formed by
deposits of protein drifting about in the vitreous
humor (the clear, jelly-like substance that fills the
middle of the eye). The appearance of permanent or
recurring white or black spots in the same area of
the field of vision may be an early warning sign of
cataracts or other serious problems.
eye
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F 1
Chemical symbol for the element flourine.
2
Abbreviation for Fahrenheit.
3
The symbol for the
coefficient of inbreeding. See also 
coefficient of
inbreeding.
Fabry disease
A genetic disease caused by a
mutation in the GLA gene, resulting in a deficiency
of the enzyme alpha-galactosidase A, also known as
ceramide trihexosidase. This enzyme is essential to
the metabolism of a fat compound known as globo-
triaosylceramide. Without alpha-galactosidase A,
this fatty substance accumulates in the walls of
blood vessels, leading to narrowing and decreased
blood flow to the tissues normally supplied by these
vessels. Small vessels in the skin, kidneys, heart, and
nervous system are preferentially affected, impair-
ing function of these organs. Males with Fabry dis-
ease are more severely affected than females with it
because the gene for Fabry disease is on the X chro-
mosome. Males have only one X, whereas females
have a second X and therefore some enzyme activity.
Females with partial enzyme activity may not show
any symptoms, or may have symptoms as severe as
affected males. Diagnosis is made by determining
the level of alpha-galactosidase A in blood plasma
or through genetic testing. Symptoms may include
blood vessel-filled skin lesions known as angioker-
atomas over the hips, buttocks, thighs, and lower
belly with fever accompanying attacks of pain in the
fingers and toes. Potentially life-threatening compli-
cations such as stroke, heart failure, and kidney
failure may also occur. Treatment includes intra-
venously-administered enzyme replacement therapy
with agalsidase beta (brand name: Fabrazyme),
which reduces the fat accumulation in many types of
cells and tissues. Episodes of pain in the hands and
feet may benefit from medications such as diphenyl-
hydantoin (brand name: Dilantin) or carbamazap-
ine (brand name: Tegretol). Also known as
Anderson-Fabry disease and angiokeratoma cor-
poris diffusum universale.