Familial Hypercholeterolemia Essay, Research Paper
Familial Hypercholesterolemia
Familial Hypercholesterolemia, a very dangerous and deadly genetic
disease, has the potential to be passed via the parent?s DNA from one generation
to the next. Although it is not common, people who suffer from this genetic flaw
often times lead very short lives, as it increases their susceptibility to a wide range
of other complications that can ultimately lead to death (Varret, 1999).
Familial Hypercholesterolemia (FH) operates by not allowing cholesterol to
move into the cells via the blood stream. This is due directly to the fact that
protein receptors on the surface of the cell responsible for the uptake of cholesterol
are either damaged or not present. The mutation occurs in the DNA that encodes
the information for the structure of the LDL receptors (Metabolic, 1999). Thus
LDL, known as Low Density Lipoprotein, slowly begins to accumulate and form
deposits in various parts of the body, where it ultimately begins to cause serious
side effects.
LDLs are responsible for transporting cholesterol from the site of its
production in the liver to various parts of the body?s cells. Once it reaches its
designated target, the cholesterol is separated from its lipoprotein and used by the
cell. However, because this mechanism is faulty in people who suffer from this
genetic disease, unusually large amounts of LDL begin to build up in the blood
vessels (Familial, 1999). To compound this problem further, when sufficient
levels of cholesterol are registered within the cells, the cholesterol-synthesizing
enzymes stop producing more cholesterol. However, since the cell never takes in
this cholesterol, the body believes there is a shortage, and continues to produce
more (Metabolic, 1999). Patients who suffer from homozygous FH have
cholesterol levels between 700 to 1,200 mg/dL, while those who suffer from
heterozygous FH have cholesterol levels between 350 to 500 mg/dL. These levels
are extremely high, as the average cholesterol level for a healthy man is close to
200 mg of cholesterol per 100 cc of blood plasma (Familial, 1999). Thus, an
extremely high level of cholesterol is often times one of the first indicators that a
person may suffer from Familial Hypercholesterolemia.
One of the most obvious effects of Familial Hypercholesterolemia is the
development of tendon xanthoman. Xanthomas are extremely painful lesions that
are caused by large cholesterol deposits is many parts of the body. The most
common place for these to occur are in the tendons of the hands as well as the
eyelids (Metabolic, 1999).
However, the greatest risk that people with this disease face is the
development of cardiac complications that often times results in an early death
(Varret, 1999). As large amounts of cholesterol begin to build up in the blood
stream, it begins to form deposits inside the blood vessels. This condition is
known as Arteriosclerosis, which effects the vessels of the body that carry oxygen
rich blood from the heart to the rest of the body. The deposits, which are also
known as plaque, are formed by the interaction of free radicals and LDL within the
blood vessels (Familial, 1999). The most common type of arteriosclerosis is
atherosclerosis, an acquired heart disease with many severe complications.
Atherosclerosis is a type of hardening and thickening of the medium and large
sized arteries, which results in a loss of elasticity (Metabolism, 1999). As large
amounts of cholesterol-carrying lipoproteins are deposi
arteries, the vessel channels begin to narrow and ultimately interferes with the
flow of blood. In addition to these fatty deposits, calcification may occur as well
as the development of scar tissue. This results in extremely high blood pressure or
hypertension for patients suffering from Familial Hypercholesterolemia. As these
channels become even more narrow, blood clots begin to form over the rough
walls of the artery, causing a condition known as thrombosis. Although these
symptoms may occur in an artery of the body, atherosclerosis causes most of its
damage by restricting blood flow to crucial areas of the body such as the heart,
brain, kidneys, and legs (Metabolisms, 1999).
When atherosclerosis effects the coronary arteries, heart attacks often occur
as well as cases of ischemic heart disease. Both of these cases occur when their is
not enough oxygen rich blood reaching the heart muscle because of the narrowing
or blocking of the coronary artery by fatty deposits (Familial, 1999). If the oxygen
depletion is extreme a condition known as myocardial infarction may occur. This
is when a section of the heart muscle dies, causing the crushing chest pains of a
heart attack. However, if their is only a slight shortage of oxygen rich blood to the
heart, a condition known as angina pectoris will develop. Angina pectoris is
marked by a powerful squeezing sensation under the breastbone which often
travels into the arm, lasting several minutes.
Atherosclerosis is also responsible for strokes in people suffering from FH.
If the arteries to the brain are blocked, the decrease in blood flow and oxygen
causes personality changes and mental confusion (Metabolism, 1999). Thus, a
stroke may occur when arteries weakened by atherosclerosis rupture, causing a
complete halt of blood flow to the brain. Partial paralysis, loss of speech, and
death are all possible consequences of the shortage of blood to the brain.
In today?s society, many people consume a diet high in fat and cholesterol
without any knowledge of what they are subjecting their body to. People who
suffer from Familial Hypercholesterolemia should serve as a lesson to those who
feel that eating high levels of cholesterol will not effect their body (Familial,
1999). Ultimately, those who do not suffer from Familial Hypercholesterolemia
will suffer the same fate as those who consume a diet rich in cholesterol. The only
difference coming in the fact that people with FH will face the consequences of
their genetic disease within the first 15-30 years of their life (Bishop, 1994).
However, for others who do not have this disease, they will face the same
consequences within 40-70 years of their life. Complications such as strokes,
heart attacks, pain of the angina pectoris, and the development of tendon
xanthomas will haunt them for the rest of their lives.
1. Bishop, Jerry E. ?One of the First Successful Cases of a Gene Put Permanently in a
Person is Described.? Wall Street Journal 1 Apr. 1994 : B2. Online. ProQuest. 6
Mar. 2000.
2. ?Familial Hypercholesterolemia.? HealthlinkUSA 1999. Online. AskJeeves. Available:
http:www.middlebury.edu/~cho337/ho/fh.html. 6 Mar. 2000.
3. ?Metabolic Disease: Disorders of Lipid Metabolism? Encyclopedia
Britannica 1999. Online. Microsoft Internet Explorer. 6 Mar. 2000.
4.*Varret, Mathilde. ?A Third Major Locus for Autosomal Dominant
Hypercholesterolemia Maps to 1p34.1-p32.? American Journal of
Human Genetics 64 (1999) : 1378-1387.
(* Primary Research Publication)