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 deposited on the lining of the

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)