Question 1

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

Accepted Answer

Coronary artery disease and hypertension are complex disorders that arise from an interaction between genetic and environmental factors. While lifestyle choices can contribute to the development of these conditions, they are not the sole cause. Additionally, although age, ethnicity, and gender can increase the risk of developing coronary artery disease and hypertension, they do not follow a sequential genetic pattern. Finally, while some forms of hypertension do have a genetic component, they do not typically follow an autosomal dominant pattern of inheritance. Therefore, the most accurate classification is that these conditions are complex disorders resulting from gene-environment interactions.

Question 2

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?

Accepted Answer

Epistasis is the term used to describe the gene-to-gene interaction in which the action of one gene modifies the expression of a different gene. This can occur in a variety of ways, such as when one gene masks the expression of another gene, or when two genes work together to produce a particular trait or phenotype. Heterogeneity refers to the presence of different genetic or environmental factors that can produce similar traits, while genomic imprinting involves the differential expression of genes based on which parent they are inherited from. Epigenetic penetrance refers to the degree to which a given genetic variation leads to a particular phenotype, taking into account environmental factors and other genetic influences.

Question 3

Which lethal cardiac arrhythmia can occur as a complication of long QT syndrome?

Accepted Answer

Torsade de Pointes is a life-threatening ventricular tachycardia that can occur in individuals with long QT syndrome. It is characterized by a twisting of the QRS complex around the isoelectric line on an electrocardiogram.

Question 4

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

Accepted Answer

Xanthomas, which are yellowish clusters of cholesterol deposits, are commonly seen in individuals with familial hypercholesterolemia. Lipomas (choice A) are benign fatty tumors and are not specifically associated with this condition. Osteoarthritis (choice C) is a degenerative joint disease and not directly linked to familial hypercholesterolemia. Hemangiomas (choice D) are benign tumors of blood vessels and are not a typical finding in individuals with familial hypercholesterolemia.

Question 5

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

Accepted Answer

The most common forms of atherosclerosis are influenced by multiple genetic factors, with each gene contributing a small effect. Environmental factors and lifestyle choices also play a significant role in the development of atherosclerosis. There is no evidence to support choices B, C, or D.

Question 6

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

Accepted Answer

People who are homozygous for familial hypercholesterolemia have very high levels of plasma cholesterol, typically ranging from 600 mg/dL to 1200 mg/dL. This is due to a genetic mutation that disrupts the normal function of LDL receptors in removing cholesterol from the bloodstream. This leads to the accumulation of LDL cholesterol in the blood, increasing the risk of cardiovascular disease. The other answer choices represent cholesterol levels that are within the normal or mildly elevated range.

Question 7

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

Accepted Answer

Fabry disease is associated with an increased risk for stroke due to its effects on the cardiovascular system, leading to accelerated atherosclerosis and thrombosis. Gaucher disease, Hurler syndrome, and Tay-Sachs disease do not have a known association with an increased risk for stroke.

Question 8

What do the known monogenic disorders that result in the expression of hypertension have in common?

Accepted Answer

The known monogenic disorders that result in the expression of hypertension all involve excessive kidney reabsorption of sodium, which leads to an increase in blood volume and ultimately, hypertension. Examples of such disorders include Liddle syndrome, Gordon syndrome, and pseudohypoaldosteronism type 2.

Question 9

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

Accepted Answer

Familial hypercholesterolemia is a genetic disorder that causes very high levels of LDL (bad) cholesterol. While diet and exercise are important for overall health, they may not be enough to significantly lower cholesterol levels in individuals with this condition. The most effective treatment is often a lipid-lowering drug, such as a statin, which should be taken as prescribed by a healthcare provider. Eliminating animal fats and increasing fruit intake may be beneficial as part of a heart-healthy diet, but are not the primary focus for blood cholesterol reduction in individuals with familial hypercholesterolemia.

Question 10

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

Accepted Answer

Early onset of coronary artery disease, especially before age 50, suggests a stronger genetic component, as environmental factors typically take longer to manifest in such severe forms.

Question 11

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

Accepted Answer

Factor V Leiden disorder is a genetic condition that leads to an increased risk of developing blood clots. The mutation causes factor V, a protein that helps with blood clotting, to become resistant to the anticoagulant effect of activated protein C. This results in an excess of clotting activity, leading to thrombophilia. The platelet activity is not impaired, atherosclerosis is not related to Factor V Leiden disorder, and excessive bleeding episodes would not be expected with this disorder.

Question 12

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

Accepted Answer

Determining the genetic contribution to the onset of stroke is difficult because stroke classification and phenotype remain heterogeneous, making it hard to isolate specific genetic factors.

Question 13

Which statement about atrial fibrillation is correct?

Accepted Answer

Atrial fibrillation is a complex condition with multiple genetic, environmental, and lifestyle factors contributing to its expression. While genetic predisposition plays a role, it is not the most common genetic cardiac disorder in the world, and it can occur in individuals of all ages (though it is more common in older adults). It is not associated with long QT syndrome.

Question 14

Which problem is associated with Tangier disease as an increased risk for coronary artery disease?

Accepted Answer

Tangier disease is characterized by low levels of high-density lipoproteins (HDLs), which are important for removing excess cholesterol from arteries. Without enough HDLs, cholesterol can accumulate in arteries and increase the risk for coronary artery disease. Low levels of triglycerides and high levels of LDLs are not specifically associated with Tangier disease.

Quiz 11: Cardiovascular Disorders