Wednesday 21 November 2007

Treatment of genetic diseases: in the real world. 1. familial hypercholesterolemia

One of the most common misunderstanding or negative attitudes towards genetic diseases is Genetic diseases can not be treated. They may sometimes hear about gene therapy, cloning or other advanced knowledge requirement to understand, so they leave genetics at the corner of their mind. But what do genetics doctors say?
I have to say that there are thousands of genetic diseases (and this long list is growing rapidly) that are treated or can be prevented with drugs, diet therapy, or surgical procedures effectively.
For emphasizing this promising areas of medicine, I will list these genetic diseases and their management that change their hopeless life to the bright new one.
The first one I'd like to mention is familial hypercholesterolemia.

Familial hypercholesterolemia
Familial hypercholesterolemia is one of the most common genetic diseases in the world; the prevalence of heterozygous (get one abnormal gene from only one parent) affected people is about 1 in 500, which equal to prevalence of stroke in England.
Affected people have consistenly high levels of low density lipoprotein (LDL or bad cholesterol) which leads to premature atherosclerosis of the coronary arteries, cerebral arteries and peripheral vessels. Typically in affected men, heart attacks occur in their 40s to 50s, and 85% of men with this disorder have experienced a heart attack by age 60. The incidence of heart attacks in women with this disorder is also increased, but happens 10 years later than in men.
In homozygous (receive abnormal genes from both parents) individuals the condition is more severe, and cholesterol values may exceed 600 mg/dl (normal not exceed 200 mg/dl) These individuals develop waxy plaques (xanthoma) beneath the skin over their elbows, knees, buttocks. These are deposits of cholesterol in the skin. In addition, they develop deposits in tendons, and around the cornea of the eye. atherosclerosis begins before pubery and heart attacks and death may occur before age30, or they may require higly invasive surgery such as a liver transplant. Fortunately homozygous individulas are extremely rare in about 1 in million.

Hetrozygous patients may respond well to diet modifications combined with strong lipid lowering agents which have a class name statins.
Statins are the most common and one of the most prescribed drugs nowadays for treatment of high blood cholesterol. Most of high blood cholesterol individuals are partially inherited, but not in the case of familial hypercholesterolmeia which transfer to the next generation at rate about 50 %.
There are many guidelines for managing affected individulas.
Statins provides excellent control of inherited high cholestrol levels. The statins work by reducing the manufacture of cholestrol by cells. This stimulated LDL receptor gene expression. As a result, the receptors produced by the normal gene wil reduce cholesterol levels. the effect of statins can be enhanced by bile acid sequestants or cholesterol absorption inhibitors such as plant sterols or the recently introduced drug, ezetimibe.
Many patients with FH can achieve target cholesterol levels.

STATIN TREATMENT OF FH MALES IS ONE OF HE MOST COST_EFFECTIVE MEDICAL INTERVENTIONS AVAILABLE AND SEVERAL LINE OF EVIDENCE POINT TOWARDS MAJOR IMPROVEMENTS IN CARDIOVASCULAR EVENT RATES AND TOTAL MORTALITY(DEAD) OF FH PATIENTS.
These are the names of drugs can be used for Familail Hypercholesterolemia:
Lipitor from Pfizer : Atorvastatin
Crestor from Aventis: Rosuvastatin
high dose Zocor from Merck: simvastatin
Ezetrol from Merck: ezetimibe in combination with Zocor

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