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Medical Genetics-Q bank-Set 2

1. Autosomes:

Select the best answer

a. Non-sex chromosomes

b. A missing chromosome

c. Expansion of a trinucleotide

d. Added or missing chromosomes

2. Allele:

Select the best answer

a. Female has only one X chromosome so manifests X-linked recessive condition

b. Traits, gene products, or disorders that are determined by different loci

c. Replacement of one base for another within the coding region of the genome

d. One of two or more alternative forms of a gene which may occupy a given locus

3. Phenotypic features:

Select the best answer

a. Alternate centromeres travel to opposite poles. Results in gametes with complete genetic

complement including translocation

b. The formation of four chromosomes at a cross-shaped configuration to make up for

translocations on the chromosomes during pachytene stage of meiosis I

c. Deletion or insertion of one or more bases into the coding region such that the reading

frame and thus every codon past the mutation is altered

d. The physical features that make up each individual. Often, individuals with genetic

conditions will have particular phenotypic features

4. Tetraploidy:

Select the best answer

a. 69 chromosomes

b. Trisomy 16

c. Trisomy 21

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d. 92 chromosomes

5. A child with cleft palate, a heart defect, and extra fifth fingers is found to have

46chromosomes with extra material on one homologue of the chromosome 5 pair. This

chromosomal abnormality is best described by which of the following terms?

A. Polyploidy

B. Balanced rearrangement

C. Ring formation

D. Mosaicism

E. Unbalanced rearrangement

6. A 10-year-old boy is referred to the physician because of learning problems and a lack of

motivation in school. His family history is unremarkable. Physical examination is normal except

for single palmar creases of the hands and curved fifth fingers (clinodactyly). The physician

decides to order a karyotype. Which of the following indications for obtaining a karyotype

would best explain the physician's decision in this case?

A. A couple with multiple miscarriages, or a person who is at risk for an inherited chromosome

rearrangement

B. A child with ambiguous genitalia who needs genetic sex assignment

C. A child with an appearance suggestive of Down syndrome or other chromosomal disorder

D. A child with mental retardation and/or multiple congenital anomalies

E. A child who is at risk for cancer

7. Chromosomal analysis reveals a 47,XYY karyotype. Which of the following descriptions best

fits this abnormality?

A. Autosomal trisomy

B. A male with Klinefelter's syndrome

C. Sex chromosome aneuploidy

D. A female with Turner's syndrome

E. Sex chromosome triploidy

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8. Which of the following karyotypes is an example of aneuploidy?

A. 46,XX

B. 23,X

C. 69,XXX

D. 92,XXXX

E. 90,XX

9. Which of the following is the proper cytogenetic notation for a female with Down syndrome

mosaicism?

A. 46,XX,+21/46,XY

B. 47,XY,+21

C. 47,XXX/46,XX

D. 47,XX,+21/46,XX

E. 47,XX,+21(46,XX)

10. From the list below, choose the most suitable words to complete the sentence.

Mutations are changes which occur in a (i) or a (ii)..... If a mutation occurs in a cell which

is going to form a (iii).. the mutation may affect the whole (iv) which develops.

Down syndrome results from a (v). mutation in the (vi)...

A. Cells

B. Gene

C. Gamete

D. Chromosome

E. Organism

F. Ovum

(i) B

(ii) D

(iii) E

(iv) C

(v) F

(vi) A

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11. Which of the following chromosomal alterations would you expect to have the most drastic

consequences?

(a) Inversion

(b) Duplication

(c) translocation

(d) Deletion

12. The most common lethal genetic disease in the United States is:

(a) sickle-cell anemia

(b) Cystic fibrosis

(c) Huntington disease

(d) Hemophilia

13. Which of the following is not needed for DNA replication?

(a) Ribosomes

(b) DNA

(c) nucleotides

(d) enzymes

14. Several inherited disorders are much more common in close-knit religious communities,

such as the Amish (Jews), than in the general population. This is at least partly due to the fact

that:

(a) people in such communities are more likely to marry relatives

(b) shared environmental conditions such as diet can increase mutation rate

(c) modern medical care is not widely available in such communities

(d) community members care for each other and disorders are passed on

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15. John and Jesica are planning a family, but since each has a brother who has sickle cell

anemia, they are concerned that their children may develop sickle-cell disease. Neither John,

Jane nor their respective parents have the disease. They consult a genetic counselor who tells

them:

(a) there is very little chance that any of their children will have sickle-cell disease

(b) that all of their children will have sickle-cell disease

(c) that one out of four of their children could be expected to have sickle cell-disease

(d) that its possible that none of their children will have the disease but blood tests on them

both will be required to make sure

16. Why is sickle cell disease so called?

(a) because it makes people sick

(b) its named after a special type of white blood cell

(c) pH changes in the blood cells make them collapse into a sickle shape

(d) because its caused by an infectious microorganism that has sickle shaped cells

17. In people with sickle cell disease the red blood cells breakdown, clump, and clog the blood

vessels. The broken cells accumulate in the spleen. Among other things, this leads to physical

weakness, heart failure, pain, brain damage and spleen damage. Affected individuals become

paralyzed and can develop rheumatism, pneumonia and other diseases and kidney failure. This

is an example of:

(a) the polygenic nature of sickle cell disease

(b) the pleiotropic effects of the sickle cell allele

(c) an epistatic interaction between the sickle cell allele and a proteolytic enzyme gene

(d) infectious organisms acting on the sickle cell allele

18. Heart disease, diabetes, cancer, alcoholism and many mental illnesses can best be described

as:

(a) symptoms of a bad life-style

(b) infectious diseases caused by microorganisms

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(c) multifactorial disorders with a possible polygenic component

(d) all symptoms of Huntingtons disease

19. The genetic disease cystic fibrosis is caused by a defective allele that:

(a) produces a dysfunctional enzyme that fails to break down brain lipids

(b) causes hemoglobin molecules to collapse

(c) produces a defective chlorine-channel membrane transport protein

(d) produces a neurotoxin

20. Huntingtons disease is an example of a genetic disorder caused by:

(a) a late-acting lethal dominant allele

(b) a non-lethal dominant allele

(c) a late acting recessive allele

(d) homozygous recessive alleles

21. Human males are much more likely to be have hemophilia (a failure of blood to clot

properly) than human females. This is the case because:

(a) hemophilia is a contagious disease to which males are more susceptible

(b) the gene for hemophilia is carried on the Y chromosome

(c) hemophilia is carried on the autosomes

(d) the gene for hemophilia is sex-linked

22. A linkage map:

(a) orders genes on a chromosome based on recombination frequencies

(b) can only be constructed for sex chromosomes

(c) orders genes on a chromosome based on their location with respect to a stained band

(d) shows the actual ordering and spacing of genes on a chromosome

23. Duchenne muscular dystrophy is caused by a sex-linked recessive allele. Its victims are

almost invariably boys, who usually die before the age of 20. Why is this disorder almost never

seen in girls?

(a) Sex-linked traits are never seen in girls

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(b) The allele is carried on the Y chromosome

(c) Nondisjunction occurs in males but not in females

(d) In order to express an X-linked recessive, a female must have two copies of the gene

24. which of the following human genetic disorders is sex linked?

(a) Hemophilia

(b) PKU

(c) cystic fibrosis

(d) achondroplasia

25. Which of the following is correct with regard to aneuploidy?

(a) inversion

(b) 2n + 1

(c) All aneuploid individuals die before birth

(d) 4n

26. If a fragment of a chromosome breaks off and then reattaches to the original chromosome

but in the reverse direction, the resulting chromosomal abnormality is called:

(a) a deletion

(b) an inversion

(c) a translocation

(d) a nondisjunction

27. Why are individuals with an extra chromosome 21, which causes Down syndrome, more

numerous than individuals with an extra chromosome 3 or chromosome 16?

(a) There are probably more genes on chromosome 21 than on the others

(b) Chromosome 21 is a sex chromosome and 3 and 16 are not

(c) Down syndrome is not more common, just more serious

(d) Extra copies of the other chromosomes are probably fatal

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28. Each cell in an individual with Down syndrome contains ____ chromosomes:

(a) 47

(b) 22

(c) 24

(d) 45

29. Disorders involving unusual numbers of sex chromosomes show that maleness is caused by

the:

(a) presence of an X chromosome

(b) presence of a Y chromosome

(c) absence of an X chromosome

(d) absence of a Y chromosome

30. A particular allele can have different effects if it was inherited from a male rather than a

female. This phenomenon is known as:

(a) extranuclear inheritance

(b) genome imprinting

(c) sex-linkage

(d) Prader-Willi syndrome

31. Human mitochondria:

(a) are inherited as an X-linked trait

(b) are all inherited from the father

(c) have linear DNA

(d) are all inherited from the mother

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32. A genetic defect in humans results in the absence of sweat glands in the skin. Some men

have this defect all over their bodies, but in women, it is usually expressed in a peculiar way. A

woman with this defect typically has small patches of skin with sweat glands and other patches

where sweat glands are lacking. This pattern suggests the phenotypic effect of:

(a) a mutation

(b) chromosome inactivation

(c) RNA splicing

(d) an operon

33. Leber's hereditary optic atrophy is caused by a mutation in:

a) chromosome 12

b) chromosome 18 c) chromosome 21 d) mitochondrial DNA

34. Cancer causing agents are called:

A. Carcinogens

B. Mutagens

C. Teratogens

D. Tumorgens

35. Most human cancers are caused by:

A. Cancer viruses

B. Chromosomal arrangements

C. Inherited disorders

D. Environmental factors

E. Nuclear radiation

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36. Cancer cells:

A. Divide uncontrollably and then die

B. Are particularly sensitive to extracellular messages

C. Divide uncontrollably and are immortal

D. Are impossible to grow in culture

E. All of these

37. In normal differentiated somatic cells, telomerase:

A. Actively adds material to the ends of chromosomes with each cell division

B. Is not expressed and telomere tips erode with each division

C. Removes telomere tips with each division

D. Is overexpressed and cells undergo apoptosis

E. Repairs double strand breaks in DNA

38. Cancer cells are not:

A. Contact inhibited

B. Transplantable

C. Invasive

D. De-differentiated

E. Immortal

39. A cancer that spreads is termed:

A. Benign

B. Carcinogenic

C. Metastatic

D. Mutagenic

E. Apoptotic

40. A proto-oncogene can become an oncogene when:

A. It is shut off

B. It is translocated next to a highly expressed gene

C. Growth factors decrease cell division rate

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D. A person is exposed to pesticides

E. It is functioning normally

41. _______ is a type of cancer-causing gene that promotes cancer by activating cell division at

an inappropriate time or place:

A. Mutated DNA repair gene

B. Tumor suppressor gene

C. Oncogene

D. Proto-oncogene

E. Teratoma

42. The oncogene that causes Burkitt's lymphoma results from:

A. A translocation that moves a proto-oncogene next to an antibody gene

B. An inversion that places a proto-oncogene next to a transcription factor gene

C. A point mutation in a proto-oncogene

D. A virus that inserts next to a proto-oncogene

E. A deletion of an anti-oncogene

43. The Philadelphia translocation involves:

A. An exchange between chromosomes 9 and 22

B. An exchange between chromosomes 8 to 14

C. Translocation between chromosome 15 and 17

D. A fusion between chromosomes 14 and 21

E. A deletion of whole sets of chromosomes

44. Chronic myeloid leukemia is caused by a translocation that creates:

A. A proto-oncogene

B. A fusion protein that acts like a transcription factor

C. A protein that increases growth factor production

D. A fusion protein that deregulates the cell cycle of myeloid white blood cells

E. A deletion of a whole chromosome

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45. Genes that normally prevent cell division are:

A. Tumor suppressors

B. Transcription factors

C. Proto-oncogenes

D. Growth factors

E. Oncogenes

46. Loss of tumor suppression in a cell usually results from:

A. Cytokine activation of a tumor suppressor gene

B. A translocation of a tumor suppressor gene

C. An inversion involving a tumor suppressor gene

D. A deletion of a tumor suppressor gene

E. Activation of a proto-oncogene by a virus

47. The childhood kidney cancer Wilms' tumor is caused by:

A. Activation of an oncogene

B. Translocation of an oncogene

C. Loss of a tumor suppressor gene

D. A transposon

E. Deletion of whole sets of chromosomes

48. Formation of a retinoblastoma eye tumor requires:

A. A germinal mutation in one RB allele

B. A somatic mutation that turns on the RB gene

C. A germinal mutation in one RB allele, then a somatic mutation in the other allele

D. A germinal mutation in the dominant RB allele

E. Activation of the X-linked oncogene RB

49. A cytogenetic diagnosis of chronic myeloid leukemia is made by identification of:

A. Barr bodies

B. Viral infection

C. Promyelocytes

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D. The Philadelphia chromosome

E. Inactivated telomeres

50. With a germ-line mutation:

A. An oncogene is activated in some cells and a tumor suppressor deleted in others

B. Only some cells are affected

C. Two somatic mutations occur

D. All cells are affected

E. Whole sets of chromosomes are deleted

51. The main gatekeeper for FAP colon cancer is most likely:

A. APC

B. TGF

C. P53

D. PRL-3

E. RB

52. The first step in FAP colon cancer usually involves mutation of the _______ gene:

A. APC

B. TGF

C. P53

D. PRL-3

E. RB

53. Which of the following is a tumor suppressor gene instead of an oncogene?

A. Ras

B. Myc

C. P53

D. Abl

54. Which statement is true?

A. All people who inherit proto-oncogenes develop cancer

B. All people who inherit the p53 gene develop cancer

C. Most cancers are caused by a series of genetic changes

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D. Oncogenes and tumor suppressors act by the same mechanism

E. None of these statements are true

55. Growth of new blood vessels in and around tumors is called:

A. Invasiveness

B. Angiogenesis

C. Metastasis

D. Dedifferentiation

E. Apoptosis

56. BRCA1 and BRCA2 mutations:

A. Are X-linked

B. Are incompletely penetrant

C. Result from translocations

D. Occur only in malignant breast tumors

E. Always lead to cancer

57. Which type of study would compare the incidence of colon cancer among Japanese and

Americans of Japanese descent?

A. Clinical

B. Population

C. Prospective

D. Case-control

E. All of these

58. Which of these are thought to have anti-cancer benefits?

A. Heterocyclic aromatic amines (HAs)

B. Cruciferous vegetables such as broccoli

C. Red meats

D. Baked potatoes

E. Fried foods

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59. The BRAC1 gene is involved in regulating:

A. Cell division

B. Cell death

C. DNA repair

D. DNA replication

E. Apoptosis

60. Although BRAC2 was initially found associated with breast cancer, it also increases the risk

for cancers in the _______

A. Colon

B. Pancreas

C. Stomach

D. All of these

61. DNA microarrays and human genome data are being used to diagnose and manage cancer:

A. True

B. False

62. Which of the following are thought to lower the risk of developing cancer?

A. Avoiding cigarette smoke

B. Avoiding excess exposure to the sun

C. Eating less meat and more whole grains and vegetables

D. Eating cruciferous vegetables

E. All of these

63. Which of the following are known to cause cancer?

A. Viruses

B. Radiation

C. Chemicals

D. All of these

64. A benign tumor is one that invades locally and metastasizes to distant sites:

A. True

B. False

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65. Most carcinogens are also mutagens:

A. True

B. False

66. Sporadic cancers result from:

A. Somatic mutation

B. Germline mutation

C. Inherited mutation

D. All of these

67. Cancer cells probably arise frequently but are detected and eliminated by our immune

system:

A. True

B. False

68. _______ cells are commonly used today in research laboratories. They are from a cervical

cancer patient who died in 1951:

A. HeLa

B. PSA

C. AML

D. CML

69. Cancer cells are considered to be:

A. Transplantable

B. Heritable

C. Dedifferentiated

D. Invasive

E. All of these

70. All of the following are correct except:

A. Gatekeeper genes regulate mitosis and apoptosis

B. Caretaker genes control mutation rates of gatekeeper genes

C. Proto-oncogenes normally regulate the cell cycle

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D. Oncogenes are often overexpressed in cancer cells

E. Tumor suppressor genes are often overexpressed leading to cancer

71. A pedigree chart shows:

a. The genotypic ratios of the offspring

b. The types of gametes produced by the parents

c. The pattern of inheritance of a specific gene

d. Which genes are co-dominant

e. The genotypes of any parents

72. Normal human eggs have:

a. 22 autosomes and an X chromosome

b. 22 autosomes and a Y chromosome

c. 23 autosomes

d. 46 chromosomes

73. Which statement concerning a pair of alleles for a gene controlling a single characteristic in

humans is true?

a. Both genes come from the father

b. Both genes come from the mother

c. One gene comes from the mother and one gene comes from the father

d. The genes come randomly in pairs from either the mother or father

74. An extra finger in humans is rare but is due to a dominant gene. When one parent is normal

and the other parent has an extra finger but is heterozygous for the trait, what is the

probability that the first child will be normal?

a. 0%

b. 25%

c. 50%

d. 75%

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The following two (75 and 76) questions are based on the pedigree:

75. The characteristic indicated by the blackened figures is probably:

a. Dominant

b. Recessive

c. Non-dominant

d. Sex-linked recessive

76. What are the genotypes of the parents?

a. Both are homozygous dominant

b. Both are heterozygous dominant

c. Both are homozygous recessive

d. The male is homozygous dominant; the female is homozygous recessive

77. Which of the following is not a tumour suppressor gene?

a) APC

b) NF1

c) RB1

d) RET

78. Which of the following is not a familial cancer syndrome?

a) Familial adenomatous polyposis

b) Li-Fraumeni syndrome

c) Von Hippel-Lindau syndrome

d) Waardenburg syndrome

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79. Male breast cancer is associated with mutations in:

a) BRCA1

b) BRCA2

c) NF1

d) RET

80. Complete the following sentence. The Philadelphia chromosome (associated with chronic

myelogenous leukemia):

a) is an example of gene amplification

b) is a product of a reciprocal translocation

c) causes Burkitt's lymphoma

d) causes retinoblastoma

81. Which of the following would result in Angelman syndrome?

a) Maternal UPD 15

b) Paternal UPD 15

c) Deletion in the paternally derived chromosome 15

d) A mutation in the SNRPN promoter

82. Consanguinity shows a strong association with which pattern of inheritance?

a) Autosomal dominant

b) Autosomal recessive

c) X-linked dominant

d) X-linked recessive

83. Which of the following is a feature of X-linked dominant inheritance?

a) Parental consanguinity

b) Male to male transmission

c) Transmission only by females

d) Transmitted by males only to females

84. The presence of an extra digit is referred to as:

a) arachnodactyly

b) brachydactyly

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c) clinodactyly

d) polydactyly

85. A baby born with pulmonary hypoplasia secondary to oligohydramnios caused by renal

agenesis would be classified as having:

a) an association

b) a dysplasia

c) a sequence

d) a syndrome

86. The proportion of babies that have an abnormality identifiable at birth is:

a) 1 in 10

b) 1 in 40

c) 1 in 100

d) 1 in 500

87. Marked microsatellite instability is a feature of:

a) familial adenomatous polyposis

b) hereditary non-polyposis colon cancer (HNPCC)

c) multiple endocrine adenomatosis type 2

d) neurofibromatosis 1

88. Which of the following conditions is caused by a trinucleotide (triplet) repeat expansion?

a) Cystic fibrosis

b) Duchenne muscular dystrophy

c) Huntington disease

d) Osteogenesis imperfect

89. Large triplet repeat expansions can be detected by:

a) Polymerase chain reaction

b) Single strand conformational polymorphism analysis

c) Southern blotting

(d) Western blotting

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90. The normal human chromosome diploid number is:

a) 23

b) 24

c) 46

d) 48

91. Which of the following is an example of monosomy?

a) 46,XX

b) 47,XXX

c) 69,XYY

d) 45,X

92. In a Robertsonian translocation fusion occurs at the:

a) telomeres

b) centromeres

c) histones

d) ends of the long arms

93. The presence of two or more cell lines from different zygotes in a single individual is known

as:

a) mosaicism

b) diploidy

c) aneuploidy

d) chimaerism

94. The most common chromosome abnormality in first trimester spontaneous miscarriages is:

a) trisomy

b) monosomy

c) triploidy

d) tetrasomy

95. Which of the following karyotypes is not compatible with survival to birth?

a) 47,XY,+13

b) 47,XX,+18

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c) 47,XY,+21

d) 45,Y

96. The DiGeorge/Shprintzen syndrome is caused by a deletion in which chromosome?

a) 4

b) 7

c) 15

d) 22

97. Which of the following is not a chromosome instability syndrome?

a) Klinefelter syndrome

b) Ataxia telangiectasia

c) Fanconi anaemia

d) Bloom syndrome

98. Which of the following trisomy karyotypes has the mildest effect on human development?

a) 47,XXX

b) 47,XXY

c) 47,XX,+13

d) 47,XY,+21

99. Male to male transmission is a key feature of which pattern of inheritance?

a) Autosomal dominant

b) Autosomal recessive

c) X-linked dominant

d) X-linked recessive

100. Which of the following disorders does not show X-linked inheritance?

a) Duchenne muscular dystrophy

b) Tay-Sachs disease

c) Haemophilia A

d) Haemophilia B

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101. Autozygosity mapping is used to map disorders that show which pattern of inheritance?

a) Autosomal dominant

b) Autosomal recessive

c) X-linked dominant

d) X-linked recessive

102. Which of the following conditions shows anticipation in paternal transmission?

a) Huntington disease

b) Marfan syndrome

c) Cystic fibrosis

d) Fragile X syndrome

103. Marfan syndrome is caused by mutations in the gene which encodes _______

a) Collagen

b) Dystrophin

c) Elastin

d) Fibrillin

104. The most common cystic fibrosis mutation consists of:

a) a deletion

b) a duplication

c) a substitution

d) an insertion

105. Which of the following is not a recognized complication of cystic fibrosis?

a) Cancer of the oesophagus

b) Congenital absence of the vas deferens

c) Diabetes mellitus

d) Liver cirrhosis

106. The proportion of genes shared by first cousins is on average -----

a) 1/2

b) 1/4

c) 1/8

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d) 1/16

107. Repeat core sequences consisting of 2, 3, or 4 base pairs are known as what?

a) Single nucleotide polymorphisms (SNPs)

b) Microsatellites

c) Minisatellites

d) Satellites

108. Mutations that cause achondroplasia exert an effect, which can be classified as:

a) Dominant negative

b) gain-of-function

c) haploinsufficiency

d) loss-of-function

109. Which of the following causes female pseudohermaphroditism?

a) Androgen insensitivity

b) Campomelic dysplasia

c) Congenital adrenal hyperplasia

d) Klinefelter syndrome

110. Which of the following karyotypes is diagnostic of Down syndrome?

a) 46,XX,der(14;21)(q10;q10)pat+21

b) 47,XY,+13

c) 45,XX,rob,(14;21)(q10;q10)

d) 46,XY,t(2;3)(q21;q12)

111. If both parents are affected with the same autosomal recessive disorder then the

probability that each of their children will be affected equals ------

a) 1 in 4

b) 1 in 2

c) 2 in 3

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d) 1

112. The risk for miscarriage associated with amniocentesis is approximately -----

a) 1 in 10

b) 1 in 50

c) 1 in 100 to 1 in 200

d) 1 in 1000

113. Which of the following findings on prenatal ultrasound examination would not raise

suspicion of a chromosome abnormality?

a) Duodenal atresia

b) Holoprosencephaly

c) Hydrops fetalis

d) Monozygotic twins

114. Which of the following diagnostic techniques is of no value for the diagnosis of neural tube

defects?

a) Amniocentesis

b) Chorion villus sampling (CVS)

c) Maternal serum screening

d) Ultrasonography

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115. The maternal serum level of alpha-fetoprotein (AFP) is lower than average in which

situation?

a) Down syndrome

b) Exomphalos

c) Neural tube defects

d) Twin pregnancies

116. A 31-year-old man has a unilateral breast lump. A biopsy is performed, and the pathology

report, surprisingly, shows an early-stage carcinoma. The mans family history reveals no

history of breast cancer. What would the physician be most likely to advise?

A. Hormone studies

B. Karyotype

C. Prophylactic mastectomy

D. BRCA1 and BRCA2 gene studies for the patients younger sister

E. IQ test

117. 5-month-old girl has bilateral retinoblastoma. Neither parent has a history of having had

retinoblastoma. Chromosomal analysis of the patient's stimulated peripheral blood

lymphocytes is done; the photograph is of a representative karyotype. Which of the following

critical events has most likely resulted from an aberration involving chromosome 13?

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(A) Proto-oncogene activation

(B) Proto-oncogene amplification

(C) Proto-oncogene loss

(D) Tumor-suppressor gene activation

(E) Tumor-suppressor gene loss

118. A full-term female newborn is examined shortly after birth. She appears to be small for

gestational age, and she has excess skin on the nape of the neck and lymphedema of the hands

and feet. Chromosomal analysis shows some cells with a normal 46,XY karyotype and some

cells with a 45,X karyotype. Which of the following mechanisms best explains this cytogenetic

abnormality?

(A) Nondisjunction in mitosis

(B) Reciprocal translocation

(C) Robertsonian translocation

(D) Skewed X-inactivation

(E) Uniparental disomy

119. A 35-year-old man who works at a facility processing highly radioactive substances

accidentally receives a high, whole-body dose of ionizing radiation estimated to be 1500 rads

(15 gray). He dies 1 week later. At autopsy, histologic examination of the skin shows scattered,

individual epidermal cells with shrunken markedly eosinophilic cytoplasm and pyknotic,

fragmented nuclei. These morphologic changes most likely indicate which of the following

processes?

(A) Apoptosis

(B) Coagulation necrosis

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(C) Liquefaction necrosis

(D) Mutagenesis

(E) Tumor initiation

120. Identify which among these statements are TRUE or FALSE:

a. Around 5% of all infant deaths are due to congenital abnormalities

b. At least half of all spontaneous miscarriages have a genetic basis

c. A major congenital abnormality affects approximately one newborn baby in every 100

d. Positional talipes is an example of a disruption to normal intrauterine development

e. Multiple abnormalities are sometimes the result of a sequence

121. Identify which among these statements are TRUE or FALSE:

a. Down syndrome should more accurately be termed 'Down association'

b. Sotos syndrome (cerebral gigantism), like Down syndrome, is due to a chromosomal

abnormality

c. Spina bifida affects approximately 2 per 1000 births

d. Infantile polycystic kidney disease is an example of a condition with different patterns of

inheritance

e. Holoprosencephaly is an example of a condition with different patterns of inheritance

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122. Identify which among these statements are TRUE or FALSE:

a. Thalidomide embryopathy was an example of a disruption to normal intrauterine

development

b. Talipes may be a consequence of renal agenesis

c. Limb defects are not caused by fetal exposure to sodium valproate

d. Symmetrical defects tend to feature in a dysplasia

e. Birth defects are unexplained in 20% of cases

123. Identify which among these statements are TRUE or FALSE:

a. Congenital infection could lead to someone being both blind and deaf

b. The mid-trimester is the most dangerous time for a fetus to be exposed to a maternal

infection

c. Vertebral body defects can be a consequence of poorly treated diabetes mellitus in the first

trimester

d. A polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene is always

associated with an increased risk of neural tube defect

e. Pulmonary stenosis is a feature of Noonan syndrome and congenital rubella

124. Identify which among these statements are TRUE or FALSE:

a. Cleft lip-palate occurs more frequently than 1 in 1000 births

b. Associations generally have a high recurrence risk

c. The recurrence risk for a multifactorial condition can usually be determined by looking at

patient's family pedigree

d. One cause of holoprosencephaly is a metabolic defect

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e. Congenital heart disease affects 1 in 1000 babies

125. Cystic fibrosis is the most common autosomal recessive disorder in caucasian children with

an occurrence of 1 in 2000 in Caucasian populations and about 1/22 carriers in Caucasian

populations. Assuming that these data are applicable to a Norwegian community in U.S.A

comprising of 16000 people, the percentage of all the CF genes hidden carriers and in patients

in this community are respectively:

a. 96.2% and 3.8%

b. 97.8% and 2.2%

c. 95% and 5%

d. 99.1% and 0.99%

e. None of the data above is correct

126. The following diseases associated with various forms of genetic autosomal or X-linked

disorders have serious pathological consequences to the patient:

a. Dyschondrosteosis

b. Incontinentia pigmenti type 2

c. Rett syndrome

d. Hemophilia A

Match each of these disorders with the most appropriate description given below:

(b) Classic X-linked coagulation disorder due to the hereditary deficiency of factor VIII, which is

required for the activation of factor X in the intrinsic coagulation pathway

(d) A striking mental disorder syndrome that appears to be prenatal lethal in hemizygous

males, and preclude reproduction in affected females

(c) Example of inheritance pattern for genes located in the pseudoautosomal region of the X

and Y chromosomes that can undergo homologous recombination

(a) Lethal in hemizygous males. Female heterozygotes have a nearly totally nonrandom pattern

of X-inactivation. Nearly all X chromosomes carrying the IP2 mutant are inactive

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127. The terms:

a. incomplete penetrance,

b. variable expressivity and

c. pleiotropy

Are important in the pathology of autosomal dominant disorders. Match each of them with

the most appropriate disorder that can serve as its example:

(b) Marfan syndrome

(c) Split hand deformity

(a) Neurofibromatosis type 1

128. In the following listed characteristics of the two-hit tumor hypothesis, identify the only

three correct ones:

a. multiple tumors

b. bilateral

c. later onset

d. somatic mutation only

e. Loss of heterogeneity

129. The following diseases constitute the Chromosome Instability Syndromes

Ataxia telangiectasia

Fanconi anemia

Bloom syndrome

Xeroderma Pigmentosum:

The following statements on the syndromes are correct EXCEPT:

a. Radiography must be used extensively as part of treatment

b. Genes associated with above syndromes usually are involved with DNA repair and the

maintenance and integrity of chromosomes

c. These genes may be viewed as caretaker tumor-suppressor genes

d. There is increased risk of malignancy (leukemia) for anyone affected by any of these

diseases

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130. Analysis has suggested that the human genome consists of several broad sequence

components, among which are:

a. Single copy DNA sequences

b. Low copy number DNA sequences

c. Moderately repetitive DNA sequences

d. short interspersed nuclear elements (sine)

Match each of these with its most appropriate example:

(a) Alu family

(d) Structural proteins, hormones

(b) Ribosomal RNA genes

(c) Alpha and beta globin gene families

131. The figure below represents the pedigree of a family with neurofibromatosis type 1 with

the arrow indicating the proband. This pedigree shows a:

a. normal autosomal dominant inheritance

b. autosomal dominance inheritance with a new mutation originating from the proband

c. autosomal recessive inheritance

d. X-linked inheritance

e. None of the above

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132. The figure below is the pedigree demonstrating the recurrence of Osteogenesis imperfecta

in children with their father unaffected (arrow)

a. The father must have been a mosaic for the mutation from his germline

b. The pedigree represents a typical autosomal dominant inheritance

c. The pedigree represents a typical autosomal recessive inheritance

d. The pedigree represents an X linked inheritance

e. None of the above is correct

133. Which of the following mutations is most likely to be lethal?

A. Substitution of adenine for cytosine

B. Substitution of cytosine for guanine

C. Substitution of methylcytosine for cytosine

D. Deletion of three nucleotides

E. Insertion of one nucleotide

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134. In the following partial sequence of mRNA, a mutation of the template DNA results in a

change in codon 91 to UAA. What type of mutation is it?

88 89 90 91 92 93 94

GUC GAC CAG UAG GGC UAA CCG

A. Missense

B. Silent

C. Nonsense

D. Suppressor

E. Frame shift

135. Which one of the following causes a frame-shift mutation?

A. Transition

B. Transversion

C. Deletion

D. Substitution of purine for pyrimidine

E. Substitution of pyrimidine for purine