Familial Dyslipidemia Overview

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Questions and Answers

What typical LDL-C level range is observed in heterozygous familial hypercholesterolemia (HeFH)?

250 to 450 mg/dL (correct)

500 to 600 mg/dL

150 to 250 mg/dL

450 to 550 mg/dL

Which of the following is NOT a common physical manifestation of dyslipidemias?

Arcus cornea

Xanthelasmas

Tendon xanthomas

Tachycardia (correct)

What role do sterol transporters play in cholesterol metabolism?

They emulsify cholesterol from food.

They transport cholesterol to intestinal enterocytes. (correct)

They convert chylomicrons into remnants.

They synthesize triglycerides.

Which lipoprotein is primarily responsible for carrying triglycerides in circulation?

Very low-density lipoproteins (VLDL) Signup and view all the answers

Which factor can increase cholesterol levels as a secondary cause of dyslipidemia?

Excessive alcohol consumption Signup and view all the answers

What is the characteristic LDL-C level for patients with homozygous familial hypercholesterolemia?

Above 500 mg/dL Signup and view all the answers

What characterizes familial hypercholesterolemia?

Inheritance as an autosomal dominant trait Signup and view all the answers

Which of the following lipoproteins is primarily responsible for transporting lipids in the bloodstream?

Chylomicrons Signup and view all the answers

What happens to chylomicrons after they lose triglyceride?

They become chylomicron remnants. Signup and view all the answers

What is a primary cause of dyslipidemias related to genetic predisposition?

Familial hypercholesterolemia Signup and view all the answers

What is a primary defect in individuals with familial hypercholesterolemia?

Inability to bind LDL to its receptors Signup and view all the answers

Which lipoprotein collects excess cholesterol to return it to the liver?

HDL Signup and view all the answers

What is the prevalence of homozygotes with familial hypercholesterolemia?

1 in 1 million Signup and view all the answers

How do total cholesterol and LDL-C levels relate to each other in familial hypercholesterolemia?

They are inversely proportional Signup and view all the answers

Which of the following roles does LDL play in the body?

Delivers cholesterol to tissues Signup and view all the answers

What impact does a deficit of LDL receptors have on cholesterol metabolism?

Unregulated biosynthesis of cholesterol Signup and view all the answers

What is the main role of apolipoprotein B-containing lipoproteins?

Lipid delivery pathway Signup and view all the answers

Which condition is associated with a total cholesterol level of 300-600 mg/dL?

Heterozygous hypercholesterolemia Signup and view all the answers

What is one of the protective roles of HDL in preventing atherogenesis?

Reverse cholesterol transport Signup and view all the answers

Which enzyme is considered the rate-limiting step in the biosynthetic pathway for cholesterol?

3-hydroxy-3-methylglutaryl-coenzyme A reductase Signup and view all the answers

What are common secondary causes of hypercholesterolemia?

Hypothyroidism, nephrotic syndrome, and malabsorption Signup and view all the answers

How does HDL contribute to cholesterol homeostasis?

Through reverse cholesterol transport and ABCA-1 upregulation Signup and view all the answers

Which of the following factors is associated with an increased risk of coronary artery disease (CAD)?

High levels of C-reactive protein Signup and view all the answers

Which of the following can result in low HDL levels?

Malnutrition, obesity, or specific drugs Signup and view all the answers

What is the primary cause of primary dyslipidemia?

Genetic factors Signup and view all the answers

Which type of dyslipidemia is characterized by elevated triglycerides (TGs) ranging from 200 to 500 mg/dL?

Familial hypertriglyceridemia Signup and view all the answers

Which of the following is NOT a characteristic of familial dyslipidemias?

Acquired due to lifestyle Signup and view all the answers

What can be a consequence of familial hypertriglyceridemia when TGs exceed normal levels?

Eruptive xanthomas Signup and view all the answers

How does homozygous familial hypercholesterolemia (HoFH) compare to heterozygous familial hypercholesterolemia (HeFH) in prevalence?

HeFH is more common than HoFH Signup and view all the answers

What is the primary reason that secondary dyslipidemia occurs?

Lifestyle and diseases Signup and view all the answers

Which of the following terms is defined as a nonfatal myocardial infarction or coronary heart disease?

ASCVD Signup and view all the answers

What are the implications of elevated lipid levels caused by genetic factors?

They increase the risk of premature ASCVD Signup and view all the answers

What role do cholesterol-laden macrophages play in atherosclerosis?

They become foam cells and contribute to fatty streaks. Signup and view all the answers

What is the primary function of HDL in cholesterol transport?

To reverse cholesterol transport to the liver. Signup and view all the answers

Which enzyme is the target of statins in cholesterol synthesis?

HMG-CoA reductase Signup and view all the answers

How does oxidized LDL affect macrophages?

It inhibits nitric oxide expression, making them more toxic. Signup and view all the answers

Which of the following is a consequence of oxidized LDL on blood vessels?

Vasoconstriction due to endothelin expression Signup and view all the answers

What effect does oxidized LDL have on coagulation?

Increases plasminogen inhibitor levels Signup and view all the answers

What diagnostic test is used to assess coronary artery disease risk related to cholesterol?

Coronary calcium score Signup and view all the answers

What is a common marker used to evaluate the status of LDL and triglycerides in the bloodstream?

hsCRP Signup and view all the answers

Study Notes

Dyslipidemia

Primary dyslipidemia is inherited and caused by genetic factors that increase lipid levels.
Secondary dyslipidemia is acquired due to lifestyle, diseases, medications, or diet.
Familial dyslipidemias are a group of inherited disorders characterized by elevated lipid levels and increased risk of premature atherosclerotic cardiovascular disease (ASCVD).

Familial Dyslipidemia Types

Familial hypercholesterolemia is characterized by elevated total cholesterol and LDL-C, often caused by mutations in the LDL receptor gene.
Familial hypertriglyceridemia is characterized by elevated triglycerides, ranging from 200 to 500 mg/dL, sometimes exceeding 1,000 mg/dL.
Homozygous familial hypercholesterolemia (HoFH) is a rare form of familial hypercholesterolemia, occurring in one case per million people, leading to very high LDL-C levels.
Heterozygous familial hypercholesterolemia (HeFH) is more common, occurring in one case per 250 people, leading to moderately high LDL-C levels.

Cholesterol Absorption and Transportation

Cholesterol from food and bile is emulsified by bile acids into micelles, which bind to intestinal enterocytes.
Sterol transporters transport cholesterol and other sterols from the micelles to the enterocytes.
Triglycerides are synthesized by absorbed fatty acids and incorporated into chylomicrons, which are released into lymphatic circulation and converted to chylomicron remnants by losing triglyceride.
Hepatic LDL-receptor–related protein then takes up the chylomicron remnants.

Lipoproteins

Low-density lipoproteins (LDL) are responsible for delivering cholesterol to tissues and returning to the liver for recycling or excretion.
High-density lipoproteins (HDL) retrieve excess cholesterol from tissues and return it to the liver.
Very low-density lipoproteins (VLDL) carry lipids and triglycerides to tissues, and excess cholesterol is excreted into the bile.
Intermediate-density lipoprotein (IDL) is an intermediate between VLDL and LDL and is included in LDL-C measurement.

Lipoprotein Metabolism and Transport

Lipoproteins are carrier proteins that transport lipids through the bloodstream.
Apolipoproteins are proteins on the surface of lipoproteins that are essential for their functions.
Apolipoprotein B-containing lipoproteins make up the lipid-delivery pathway, while apolipoprotein A-1 contributes to reverse cholesterol transport.

Atherosclerosis

High levels of C-reactive protein (CRP) can indicate patients at risk of coronary artery disease (CAD).
Atherosclerotic lesions form in the artery wall due to the accumulation of LDL, which is oxidized and glycated, recruiting monocytes and promoting inflammation.
Macrophages accelerate LDL oxidation and apolipoprotein B accumulation and alters LDL-R receptors.
Oxidized LDL promotes coagulation, vasoconstriction, and inhibits nitric oxide expression, leading to the formation of foam cells which mark the earliest stage of an arterial fatty streak.

Diagnostic Tests for Dyslipidemia

Elevated levels of total cholesterol, LDL-C, triglycerides, apolipoprotein B, and hsCRP are indicators of dyslipidemia
Decreased levels of HDL-C suggest dyslipidemia.
Other diagnostic tests can be used to assess the severity of dyslipidemia including carotid ultrasound, coronary calcium score, and ankle-brachial index.

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Description

This quiz explores the different types of familial dyslipidemia, including familial hypercholesterolemia and hypertriglyceridemia. It covers both inherited and acquired dyslipidemias and their impact on health. Learn about the genetic factors, symptoms, and risks associated with these lipid disorders.