Question 1

What is the genetic contribution to the development of the most common forms of atherosclerosis?
A)Variation in a variety of genes, with each exerting a small effect
B)Disordered mitochondrial function reducing energy production
C)Genetic predisposition expressed after exposure to a viral trigger
D)Single-gene mutation following autosomal-dominant inheritance

Accepted Answer

Atherosclerosis is a common complex or multifactorial disease. The genetic contribution for the most common form is the result of problems in lots of genes working together, with each producing a small effect. The most common form is not transmitted in an autosomal-dominant fashion, is not mitochondrial, and is not the result of a viral trigger.

Question 2

Which problem associated with Tangier disease increases the risk for coronary artery disease?
A)Low levels of triglycerides
B)High levels of triglycerides
C)Low levels of high-density lipoproteins (HDLs)
D)High levels of low-density lipoproteins (LDLs)

Accepted Answer

High-density lipoproteins are the "good" cholesterol. Low levels of HDLs are associated with an increased risk for CAD regardless of LDL level. Tangier disease is an autosomal-codominant disorder that results in very low or absent levels of HDLs. It is not related to levels of LDL or triglycerides.

Question 3

What term is used to describe the gene-to-gene interaction in which the action of one gene modifies the expression of a different gene?
A)Epistasis
B)Heterogeneity
C)Genomic imprinting
D)Epigenetic penetrance

Accepted Answer

Epistasis is the term used to describe gene-to-gene interaction, where the action of one gene modifies the expression of another. Genetic heterogeneity means that there are different genetic causes of a trait. Genomic imprinting is an epigenetic process of silencing the expression of a gene. Epigenetic penetrance is not an official genetic term.

Question 4

Your 40-year-old patient is hospitalized for a myocardial infarction, but her lipid levels are normal. She says that she would like to have a genetic test to see whyshe was affected at such a young age. What do you say?
A)"Heart attacks seem to be caused by a combination of many affected genes working together as well as environmental factors. There is no single gene test that will be able to identify why this happened to you."
B)"Let's talk with your nurse practitioner about scheduling a test for familial hypercholesterolemia."
C)"You really shouldn't be concerned about your genetic risk. Because you are female, it is very low."
D)"It was just bad luck combined with the fact that you were once a smoker."

Accepted Answer

There are many factors, both genetic and environmental, that can increase clot formation in any area of the body, including in the coronary arteries. No single-gene mutation has been found to consistently increase the risk for myocardial infarctions or the conditions that promote them. Therefore, this complex health problem, even when it occurs in younger people, is still multifactorial.

Question 5

Why is determining the genetic contribution to the onset of stroke difficult?
A)Stroke classification and phenotype remain heterogeneous.
B)Comorbidities mask the symptoms and delay the diagnosis.
C)Environmental risk factors have equal contribution to the problem.
D)Often the person with a stroke cannot provide accurate family information.

Accepted Answer

Strokes are heterogeneous, which makes it difficult to classify them and sort out causes. Whenever there is a lot of variation in the phenotype, it is likely that there are different genes involved in the pathogenesis. Environmental risk factors, such as smoking, are important as well. Comorbidities also make finding genetic causes difficult. It is most likely that the genetic contribution to stroke is the result of many genes working together, with each exerting a small effect.

Question 6

The process in which gene variants interact with other gene variants to cause disease can be described by what word/phrase?
A)Phenotype variation
B)Reduced penetrance
C)Epistasis
D)Variable expressivity

Accepted Answer

A gene-to-gene interaction in which one gene can modify the effects of one or more other genes (in a positive way or a negative way) is called epistasis.

Question 7

Which health problem is the most frequent cause of sudden cardiac death among young athletes?
A)Atrial fibrillation
B)Hypertrophic cardiomyopathy
C)Familial hypercholesterolemia type 1
D)Romano-Ward form of long QT syndrome

Accepted Answer

More than one-third of young athletes, including teenagers, who die from sudden cardiac death before age 30 have hypertrophic cardiomyopathy. Many have had some symptoms of difficulty breathing with heavy exercise but have not had cardiac testing. Atrial fibrillation occurs with aging rather than in younger adults and is not induced by exercise. Familial hypercholesterolemia can result in early-age heart attacks, but most people with the problem are very exercise intolerant and do not engage in athletic activities. Romano-Ward is a congenital cardiac problem usually diagnosed in early childhood as a tachyarrhythmia. It is also fairly rare.

Question 8

Why is the mitochondrial disease MELAS, which results in stroke-like episodes in addition to encephalopathy and lactic acidosis, only transmitted by a motherand not by an affected father?
A)The mitochondria are in the cytoplasm, and virtually all the cytoplasm comes from the egg and is thus maternally inherited.
B)This is an X-linked-recessive condition, so the father can only transmit the gene to his daughters and not to his sons.
C)Mitochondria are in the cytoplasm and are not equally divided during gamete formation in meiosis.
D)MELAS reduces the percentage of Y-carrying sperm in affected males.

Accepted Answer

Mitochondria are in the cytoplasm only. A sperm does not contain cytoplasm. Thus, when an egg is fertilized, all the mitochondria in it are maternally derived, regardless of whether the zygote is a male or a female.

Question 9

Why is factor V Leiden disorder considered a form of thrombophilia?
A)Platelet activity is impaired.
B)Blood clots form more easily.
C)Atherosclerosis development is accelerated.
D)Excessive bleeding episodes occur in response to minor trauma.

Accepted Answer

Proteins of the coagulation cascade are supposed to be degraded by activated protein C (APC) so that they do not become too large or stay around too long. In people with factor V Leiden disorder, F5 (the factor V Leiden protein) is abnormal and cannot be degraded. Thus, the person experiences a state of "hypercoagulation." It is not related to platelet aggregation and results in blood clots rather than bleeding. It is a single-gene problem unrelated to atherosclerosis.

Question 10

How does factor V Leiden increase the likelihood of stroke?
A)Factor V Leiden activates protein C.
B)Factor V Leiden increases thrombin formation.
C)People affected with factor V Leiden have increased blood viscosity.
D)Affected people have a type of factor V that is resistant to activated protein C.

Accepted Answer

Forming blood clots only in areas where they are needed but not in other areas requires a balance between pro-clotting forces and anti-clotting forces. One anti-clotting force is activated protein C. This substance dissolves old clots and prevents clots from forming where they are not needed by degrading clotting factor V. Factor V Leiden is a mutated form of factor V that is not easily degraded by activated protein C. As a result, clots that are not needed can form more easily.

Question 11

Which condition or factor for coronary artery disease (CAD) suggests a greater genetic contribution than environmental contribution to its development?
A)When a person develops CAD 5 years after quitting smoking
B)When CAD occurs in a person who has normal blood pressure
C)When CAD is diagnosed in a person who is younger than 50 years
D)When low-density lipoprotein levels can be reduced by dietary changes alone

Accepted Answer

When CAD is diagnosed in a person younger than age 50 years, the genetic contribution is much greater than environmental factors compared with people who develop CAD at a later age. Even if environmental factors are strong, they require time to change healthy coronary arteries.

Question 12

What is the most accurate classification of the common forms of coronary artery disease and hypertension?
A)Secondary disorders caused by lifestyle choices
B)Sequential genetic disorders related to age, ethnicity, and gender
C)Complex disorders resulting from gene-environment interactions
D)Primary disorders with an autosomal-dominant pattern of inheritance

Accepted Answer

The most common forms of coronary artery disease (CAD) and hypertension (HTN) are considered complex (multifactorial) disorders. That means that many different gene mutations work together; some increase risk, whereas others protect against disease. In addition, environment and lifestyle factors modify the severity of disease and the chance of whether or not a person will get sick at all. Some rare cardiovascular problems have a purely genetic origin. Although both CAD and HTN are secondary to atherosclerosis, they do have both a genetic influence as well as a hereditary (lifestyle choice) influence and are not sequential disorders. (Remember that ethnicity and gender are genetically determined.)

Question 13

Your patient has been diagnosed with long QT syndrome (LQTS). What do you know about this heart rhythm problem?
A)LQTS is a congenital genetic disease that will be evident during the first 2 years of life.
B)It is relatively rare and often caused by private mutations.
C)LQTS is treated in the same way, no matter the cause.
D)Deafness always accompanies LQTS.

Accepted Answer

Quite a large number of gene mutations have been identified as being involved in the expression of LQTS. However, it is still a relatively rare cardiac syndrome. Some of the mutations involved are only present within one kindred, known as a private mutation, and testing of the mutation beyond the affected family is not beneficial.

Question 14

For patients who have familial hypercholesterolemia, what should be the focus of teaching for blood cholesterol reduction?
A)Eliminating animal fats from the diet
B)Increasing the amount of fruit in the diet
C)Exercising at least 4 to 5 hours every week
D)Taking the lipid-lowering drug as prescribed

Accepted Answer

Dietary management has been the recommended initial treatment for people with familial hypercholesterolemia, but dietary modification alone can only reduce LDL levels by about 10%, so medications are often begun early, especially the statins. The best responses are achieved when the drugs are taken exactly as prescribed. Although exercise can help lower cholesterol levels, this response requires much more than 4 to 5 hours per week.

Question 15

Which ethnic group is at higher risk for stroke caused by factor V Leiden?
A)Ashkenazi Jews
B)African Americans
C)Caucasians from Northern Europe
D)French Canadians from the Quebec area

Accepted Answer

Although strokes are more common among African Americans, factor V Leiden is more common in people whose ancestors came from Northern Europe. Between 3% and 8% of people with European ancestry are heterozygous (they inherited a mutation from one parent) for factor V Leiden. About 1 in 5,000 people are homozygous (they have inherited a mutant copy from each parent).

Question 16

Which lysosomal storage disease is associated with an increased risk for stroke?
A)Fabry disease
B)Gaucher disease
C)Hurler syndrome
D)Tay-Sachs disease

Accepted Answer

Fabry disease is a lysosomal storage disease that is transmitted in an X-linked-recessive manner. It is caused by the inability to make the enzyme alpha-galactosidase A, which is needed so that people can metabolize lipids. Without this enzyme, fat metabolism is disordered, and fats accumulate, which increases the risk for strokes. Tay-Sachs disease and Hurler syndrome both result in childhood deaths from respiratory problems, and no association between either of them and stroke risk has been found. Gaucher disease is not associated with an increased risk for stroke.

Question 17

What is true about the gene variants that cause hypertension?
A)A few genes with major contributions have been identified.
B)Genes that code for proteins in the RAAS pathways are often involved.
C)Hypertension is always secondary to another genetic disease.
D)Polymorphisms have little or no impact on the hypertensive phenotype.

Accepted Answer

The renin-angiotensin-aldosterone system (RAAS) is a pathway that regulates blood volume by controlling water and sodium retention. Blood volume is directly related to blood pressure, meaning that blood pressure increases when blood volume increases. The RAAS pathway is complex, involving many proteins and receptors, all of which are coded for by different genes. Problems in any one of them can lead to primary hypertension.

Question 18

Which total plasma cholesterol levels are most likely to be present in people who are homozygous for an allele that causes familial hypercholesterolemia?
A)100 mg/dL to 200 mg/dL
B)200 mg/dL to 300 mg/dL
C)400 mg/dL to 500 mg/dL
D)600 mg/dL to 1,200 mg/dL

Accepted Answer

Total plasma cholesterol levels in people who are homozygous for an allele that causes familial hypercholesterolemia usually range between 600 and 1,200 mg/dL. Those who are heterozygous often have levels between 300 and 400 mg/dL. The range of 100 mg/dL to 200 mg/dL is considered normal or desirable. The range of 200 mg/dL to 300 mg/dL is higher than desired but much lower than for a person who has a mutation in one or both alleles of a gene associated with familial hypercholesterolemia.

Question 19

Which variable in a person with coronary artery disease (CAD) increases the likelihood of a strong genetic influence in its expression?
A)The disorder is not present in the person's dizygotic twin.
B)The disorder is present in a woman whose father had CAD.
C)The affected person has eaten a vegetarian diet for the past 5 years.
D)The disorder is present in about 5% of the person's maternal family members.

Accepted Answer

If a woman's father had CAD, the risk of her having CAD or a myocardial infarction (MI) is 70% higher than that of a woman whose father did not have CAD. This person's maternal family members diagnosed with the disorder at a 5% incidence represents a much lower incidence than the national average. Dizygotic twins do not have identical gene sequences at all loci. So, the absence of the problem in a dizygotic twin does not support a strong genetic influence on expression of the disorder. A genetic problem can be modified somewhat but not to a great degree by dietary changes.

Question 20

Which physical finding in a 30-year-old man suggests the possibility of familial hypercholesterolemia?
A)Lipomas
B)Xanthomas
C)Osteoarthritis
D)Hemangiomas

Accepted Answer

Xanthomas are cholesterol deposits in the skin that form when blood cholesterol levels are very high. They are associated with familial hypercholesterolemia and can occur at any age. Common sites include the elbows and knees. Lipomas are benign fatty tumors and are not related to cholesterol levels. Hemangiomas are benign blood vessel tumors and are not related to cholesterol levels. Although osteoarthritis more commonly occurs in older adults, it can occur in younger adults who have a traumatic joint injury. Its presence is not associated with cholesterol levels.

Quiz 13: Cardiovascular Disorders

What is the genetic contribution to the development of the most common forms of atherosclerosis?

Which problem associated with Tangier disease increases the risk for coronary artery disease?

What term is used to describe the gene-to-gene interaction in which the action of one gene modifies the expression of a different gene?

Your 40-year-old patient is hospitalized for a myocardial infarction, but her lipid levels are normal. She says that she would like to have a genetic test to see whyshe was affected at such a young age. What do you say?

Why is determining the genetic contribution to the onset of stroke difficult?

The process in which gene variants interact with other gene variants to cause disease can be described by what word/phrase?

Which health problem is the most frequent cause of sudden cardiac death among young athletes?

Why is the mitochondrial disease MELAS, which results in stroke-like episodes in addition to encephalopathy and lactic acidosis, only transmitted by a motherand not by an affected father?

Why is factor V Leiden disorder considered a form of thrombophilia?

How does factor V Leiden increase the likelihood of stroke?

Which condition or factor for coronary artery disease (CAD) suggests a greater genetic contribution than environmental contribution to its development?

What is the most accurate classification of the common forms of coronary artery disease and hypertension?

Your patient has been diagnosed with long QT syndrome (LQTS) . What do you know about this heart rhythm problem?

For patients who have familial hypercholesterolemia, what should be the focus of teaching for blood cholesterol reduction?

Which ethnic group is at higher risk for stroke caused by factor V Leiden?

Which lysosomal storage disease is associated with an increased risk for stroke?

What is true about the gene variants that cause hypertension?

Which total plasma cholesterol levels are most likely to be present in people who are homozygous for an allele that causes familial hypercholesterolemia?

Which variable in a person with coronary artery disease (CAD) increases the likelihood of a strong genetic influence in its expression?

Which physical finding in a 30-year-old man suggests the possibility of familial hypercholesterolemia?