Chapter 6: Epigenetics and Disease MULTIPLE CHOICE
1. What genetic process is likely responsible for the occurrence o f asthma in only one of a pair
of identical twins? a. Epigenetic modifications b. Genomic imprinting
c. Transgenerational inheritance d. Methylation
A!" A
Epigenetic modifications can cause indi#iduals with the same d eo$yribonucleic acid %&A' se(uences %such as identical twins' to ha#e different disease profiles. The correct option is the only one that accurately identifies the genetic g enetic process likely responsible for the occurrence of asthma in only one of a pair of twins. )T!" 1
*E+" )age 1,- )age 1,/
0. )raderWilli )raderWilli syndrome causes a chromosomal defect that is" a. 2nitiated by postnatal e$posure to a #irus b. 2nherited from the father c. *elated to maternal alcohol abuse d. Transferred from mother to child A!" 3
)raderWilli )raderWilli syndrome can be caused by a 4 Mb deletion of chromosome 1/( when inherited from the father. The other options do not accurately identify the reason for the chromosomal damage that causes )raderWilli syndrome. )T!" 1
*E+" )ages 1,51,,
-. A malfunction in &A methylation can lead to" a. 6ypothyroidism c. 7ancer b. 3lindness d. &iabetes mellitus A!" 7
Aberrant methylation can lead to silencing of tumorsuppressor genes in the de#elopment of cancer. o research supports a connection between hypothyroidism8 blindness8 or diabetes mellitus to a malfunctioning of &A methylation. )T!" 1
*E+" )age 1,- )age 1,9
true regarding the embryonic de#elopment de#elop ment of stem cells? 4. Which statement is true regarding a. They are already differentiated. b. They are referred to as housekeeping genes. c. They already demonstrate de monstrate &A se(uencing. d. They are said to be pluripotent. A!" &
Early in embryonic de#elopment8 all cells of the embryo ha#e the potential to become any type of cell in the fetus or adult. These embryonic stem cells are cells are said to be pluripotent. The remaining options are not true statements regarding embryonic stem cell de #elopment.
)T!" 1
*E+" )age 1,4
/. When micro*A %mi*A' are methylated their messenger *A %m*A' targets are o#er
e$pressed8 the resulting effect on e$isting cancer would be" a. 7ell death c. *emission b. Metastasis d. *elapse A!" 3
When mi*A genes are methylated8 their m*A targets targets are o#ere$pressed8 and this o#er e$pression has been associated with metastasis. of the described effect on m*A targets on e$isting cancer does not result in any of the other options. )T!" 1
*E+" )age 1,9
9. The difference between &A se(uence mutations and epigenetic modifications is" a. &A se(uence mutations can be directly altered. b. :eukemia is a result of only &A se(uence mutation. c. Epigenetic modifications can be re#ersed. d. o known drug therapies are a#ailable for epigenetic modifications. A!" 7
;nlike &A se(uence mutations8 which cannot be directly altered8 epigenetic modifications can be re#ersed. The remaining options are not true statements regarding the difference between &A se(uence mutations and epigenetic modifications. modifications. )T!" 1
*E+" )age 1,9
5. Which term refers to the silenced gene of a gene pair? a. Acti#ated c. Mutated b. Altered d. 2mprinted A!" &
Gene silencing8 a process during which genes are predictably silenced8 depending on which parent transmits them8 is known as imprinting as imprinting < the transcriptionally silenced genes are then said to be imprinted . The remaining options do not accurately accu rately identify this process. )T!" 1
*E+" )age 1,5
,. The shape of the face of a child diagnosed with *ussell!il#er syndrome is likely to be" a. *ound c. Triangular b. !(uare d. Elongated A!" 7
Growth retardation8 proportionate short stature8 leglength discrepancy8 and a small8 triangularshaped face characteri=es *ussell!il#er syndrome. The other face shapes are not characteristic of *ussell !il#er syndrome. )T!" 1
*E+" )age 1,,
>. Genes responsible for the maintenance of all ce lls are referred to as" a. ;ni#ersal c. 6ousekeeping
b. Managerial
d. E$ecuti#e
A!" 7
A small percentage of genes8 termed housekeeping genes8 genes8 are necessary for the function and maintenance of all cells. The remaining options do no t accurately refer to these cells. )T!" 1
*E+" )age 1,4
1. What is the belief regarding twins who adopt dramatically different lifestyles? a. They may e$perience #ery different aging processes. b. They will retain #ery similar methylation patterns. c. They will e$perience identical phenotypes throughout their lifespans. d. They may ne#er demonstrate similar &A se(uences of their somatic cells. A!" A
Twins Twins with significant lifestyle differences %e.g.8 smoking #ersus nonsmoking'8 accumulate large numbers of differences in their methylation patterns. The twins8 despite ha#ing identical &A se(uences8 become more and more different as a result of epigenetic changes8 which in turn affect the e$pression of genes. These results8 along with findings generated in animal studies8 suggest that changes in epigenetic patterns may be an important part of the aging ag ing process. They will not e$perience identical phenotypes throughout their lifespans. )T!" 1
*E+" )age 1,/
11. 6ypomethylation and the resulting effect on oncogenes result in a%an'" a. &ecrease in the acti#ity of the oncogene8 thus suppressing cancer de#elopment b. &eacti#ation of MLH1 of MLH1 to to halt &A repair c. 2ncrease in tumor progression from benign to malignant d. @#ere$pression of micro*A8 resulting in tumorigenesis A!" 7
Tumor cells typically e$hibit hypomethylation %decreased methylation'8 which can increase the acti#ity of oncogenes. 6ypomethylation 6ypometh ylation increases as tumors progress from benign neoplasms to malignancy. @nly the correct option accurately describes hypomethylation and its resulting effects. )T!" 1
*E+" )age 1,9
10. When a chromosome lacking 4 Mb is inherited from the mother8 the child is at risk for
de#eloping which syndrome? a. )raderWilli b. Angelman
c. 3eckwithWiedemann d. *ussell!il#er
A!" 3
This anomaly illustrates the inheritance pattern of Angelman syndrome8 which can be caused by a 4 Mb deletion of chromosome 1/( when inherited from the mother. The anomaly is not the cause of any of the other options. )T!" 1 MULTIPLE RESPONSE
*E+" )age 1,5
1-. A childs childs diagnosis of 3eckwithWiedemann syndrome is supported by the presence of"
(Select all that apply.) a. An omphalocele b. eonatal hypoglycemia c. 7reased earlobes d. :ow birth weight e. A large tongue A!" A!" A8 38 38 78 78 E
3eckwithWiedemann syndrome is usually identifiable at birth because the child e$hibits a large si=e for gestational age8 neonatal hypoglycemia8 a large tongue8 creases on the earlobe8 and omphalocele. )T!" 1
*E+" )age 1,,
14. A diagnosis of Angelman syndrome in a child is supported by which assessment findings?
(Select all that apply.) a. !mall feet and hands b. )rofound cogniti#e dysfunction c. @besity d. Ata$ic gait e. 6istory of sei=ures A!" 38 &8 &8 E
A child diagnosed with Angelman syndrome demonstrates a characteristic posture8 bouts of uncontrolled laughter8 se#ere mental retardation8 sei=ures8 and an ata$ic gait. )T!" 1
