Chapter 6: Epigenetics and Disease

Question 1

What genetic process is likely responsible for the occurrence of asthma in only one of a
pair of identical twins?
a. Epigenetic modifications 
c. Transgenerational inheritance
b. Genomic imprinting 
d. Methylation

Answer 1

ANS: A
Epigenetic modifications can cause individuals with the same deoxyribonucleic acid
(DNA) sequences (such as identical twins) to have different disease profiles. The correct
option is the only one that accurately identifies the genetic process likely responsible for
the occurrence of asthma in only one of a pair of twins.
PTS: 1 REF: Page 183 | Page 185

Question 2

Prader-Willi syndrome causes a chromosomal defect that is:

a. Initiated by postnatal exposure to a virus
b. Inherited from the father
c. Related to maternal alcohol abuse
d. Transferred from mother to child

Answer 2

ANS: B
Prader-Willi syndrome can be caused by a 4 Mb deletion of chromosome 15q when
inherited from the father. The other options do not accurately identify the reason for the
chromosomal damage that causes Prader-Willi syndrome.
PTS: 1 REF: Pages 187-188

Question 3

Which statement is true regarding the embryonic development of stem cells?

a. They are already differentiated.
b. They are referred to as housekeeping genes.
c. They already demonstrate DNA sequencing.
d. They are said to be pluripotent.

Answer 3

ANS: D
Early in embryonic development, all cells of the embryo have the potential to become any
type of cell in the fetus or adult. These embryonic stem cells are said to be pluripotent. The
remaining options are not true statements regarding embryonic stem cell development.

Question 4

The difference between DNA sequence mutations and epigenetic modifications is:

a. DNA sequence mutations can be directly altered.
b. Leukemia is a result of only DNA sequence mutation.
c. Epigenetic modifications can be reversed.
d. No known drug therapies are available for epigenetic modifications.

Answer 4

ANS: C
Unlike DNA sequence mutations, which cannot be directly altered, epigenetic
modifications can be reversed. The remaining options are not true statements regarding the
difference between DNA sequence mutations and epigenetic modifications.
PTS: 1 REF: Page 18

Question 5

Which term refers to the silenced gene of a gene pair?

a. Activated
c. Mutated
b. Altered
d. Imprinted

Answer 5

ANS: D
Gene silencing, a process during which genes are predictably silenced, depending on
which parent transmits them, is known as imprinting; the transcriptionally silenced genes
are then said to be imprinted. The remaining options do not accurately identify this
process.
PTS: 1 REF: Page 187

Question 6

Hypomethylation and the resulting effect on oncogenes result in a(an):

a. Decrease in the activity of the oncogene, thus suppressing cancer development
b. Deactivation of MLH1 to halt DNA repair
c. Increase in tumor progression from benign to malignant
d. Over-expression of microRNA, resulting in tumorigenesis

Answer 6

ANS: C
Tumor cells typically exhibit hypomethylation (decreased methylation), which can
increase the activity of oncogenes. Hypomethylation increases as tumors progress from
benign neoplasms to malignancy. Only the correct option accurately describes
hypomethylation and its resulting effects.
PTS: 1 REF: Page 186

Question 7

When a chromosome lacking 4 Mb is inherited from the mother, the child is at risk for
developing which syndrome?
a. Prader-Willi c. Beckwith-Wiedemann
b. Angelman d. Russell-Silver

Answer 7

ANS: B
This anomaly illustrates the inheritance pattern of Angelman syndrome, which can be
caused by a 4 Mb deletion of chromosome 15q when inherited from the mother. The
anomaly is not the cause of any of the other options.
PTS: 1 REF: Page 187

Question 8

A child’s diagnosis of Beckwith-Wiedemann syndrome is supported by the presence of:
(Select all that apply.)
a. An omphalocele
b. Neonatal hypoglycemia
c. Creased earlobes
d. Low birth weight
e. A large tongue

Answer 8

ANS: A, B, C, E
Beckwith-Wiedemann syndrome is usually identifiable at birth because the child exhibits a
large size for gestational age, neonatal hypoglycemia, a large tongue, creases on the
earlobe, and omphalocele.
PTS: 1 REF: Page 188

Question 9

A diagnosis of Angelman syndrome in a child is supported by which assessment findings?
(Select all that apply.)
a. Small feet and hands
b. Profound cognitive dysfunction
c. Obesity
d. Ataxic gait
e. History of seizures

Answer 9

ANS: B, D, E
A child diagnosed with Angelman syndrome demonstrates a characteristic posture, bouts
of uncontrolled laughter, severe mental retardation, seizures, and an ataxic gait.
PTS: 1 REF: Page 187