Exam Questions | Molecular Detection Of Inherited – Ch.12

Chapter 12: Molecular Detection of Inherited Diseases

Multiple Choice

1. What defines a congenital disease?

A. Always heritable

B. Present at birth

C. Limited to blood disorders

D. Symptoms delayed until puberty

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2. Fertilization of gametes containing an extra copy of one chromosome will result in what chromosomal abnormality?

A. Monosomy

B. Disomy

C. Trisomy

D. Tetraploidy

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3. How are transmission patterns determined?

A. Family history

B. Karyotyping

C. Environmental studies

D. Comparison of unrelated individuals

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4. In a pedigree, an affected female will be indicated by which of the following symbols?

A. Open circle

B. Shaded circle

C. Open square

D. Shaded square

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5. In a pedigree, a deceased family member is indicated by which of the following?

A. Triangle

B. Shaded symbol

C. Slash through the symbol

D. X across the symbol

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6. Sex-linked disorders involve which of the following chromosomes?

A. X

B. 19

C. 1

D. 22

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7. Genetic analysis of four generations of a family reveals that about 50% of the males in the family are affected by a mutation and about 50% of the females are carriers of the mutation that affects the males. What type of inheritance pattern is seen in this family?

A. Autosomal dominant

B. Autosomal recessive

C. X-linked recessive

D. Y-linked recessive

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8. Seventeen members of an extended family have a gene mutation. Only two of them have the associated phenotype. What is the term for this observation?

A. Complete penetrance

B. Mosaicism

C. Autosomal-dominant inheritance

D. Incomplete penetrance

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9. All members of a family carry the same gene polymorphism associated with a certain phenotype. There is a range of phenotypes among the family members. What is the term for this observation?

A. Variable expressivity

B. Complete penetrance

C. X-linked

D. Y-linked

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10. Which of the following genetic diseases is a storage disease in which sulfatides accumulate inside the lysosomes?

A. Down

B. Niemann–Pick

C. Klinefelter

D. Pseudo-Hurler polydystrophy

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11. Li–Fraumeni syndrome, in which affected patients have an increased predisposition to cancer, is caused by a mutation in which of the following genes?

A. Hemoglobin beta

B. Dystrophin

C. Phenylalanine hydroxylase

D. TP53 tumor-suppressor gene

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12. One of the rarest genome mutations, in which the affected infant has a cleft palate, abnormal heart, and developmental delays and usually does not survive beyond 6 months because of trisomy 13, is which of the following syndromes?

A. Down

B. Turner

C. Patau

D. XYY

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13. A patient is tested for the presence of the factor V Leiden mutation by PCR-RFLP by targeting a G to A mutation in exon 10 of the factor V gene F5. Isolated DNA is amplified by PCR, and the resulting amplicons are cut with MnlI and separated by gel electrophoresis. Two bands are seen in the lane loaded with the patient's sample, one at 153 bp and the other at 67 bp. Controls were acceptable. Which of the following is the correct interpretation of these results?

A. Normal

B. Heterozygous mutation

C. Homozygous mutation

D. Wrong target and method performed for this disease

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14. A patient with abnormally high iron levels is tested to determine if hemochromatosis, specifically the C282Y mutation in the HFE gene, is the cause. The patient's DNA is isolated from whole blood and amplified. Amplicons are then cut with Rsa1, and the resulting fragments are separated by gel electrophoresis. There are no RsaI sites in the normal 250-bp PCR product, whereas the C282Y mutation generates one RsaI site. The lane containing the patient's sample has three bands at 250 bp, 140 bp, and 110 bp. Controls were acceptable. Which of the following is the correct interpretation of these results?

A. Normal

B. Heterozygous mutation

C. Homozygous mutation

D. Wrong target and method performed for this disease

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15. Mitochondrial mutations primarily affect which of the following tissues?

A. Skin

B. Bone

C. Muscle

D. Lung

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16. Which of the following syndromes is caused by deletions in mitochondrial genes as detected by Southern blot?

A. Pearson

B. Kearns–Sayre

C. Leber

D. Mitochondrial DNA depletion

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17. A patient is tested to determine the number of CGG repeats in the FMR-1 gene by Southern blot. The patient is found to have a band that runs above the normal control band. Which of the following is the correct interpretation of these results?

A. The patient is normal.

B. The patient has Huntington disease.

C. The patient has Tay–Sachs disease.

D. The patient has full fragile X mutation.

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18. A patient presented complaining of slurred speech and difficulty swallowing. The patient's DNA was tested to determine the number of CAG repeats in the Huntingtin gene by PCR. The patient had 10 to 29 repeats. This result is interpreted as which of the following?

A. The result is normal.

B. The result shows abnormal expansion consistent with Huntington disease.

C. The patient is at risk of Huntington disease.

D. The result is inconsistent, and the test should be repeated.

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19. The mutation del(15)(q11q13) on the paternal chromosome results in a disease that is different from when the same mutation occurs on the maternal chromosome. This difference results from which of the following?

A. Multifactorial inheritance

B. Imprinting

C. Hormonal differences

D. Sex linkage

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20. Missense mutations in proteins that regulate cell growth can result in which of the following diseases?

A. Familial hypercholesteremia

B. Muscular dystrophy

C. Neurofibromatosis

D. Phenylketonuria

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21. A pedigree was examined over four generations of a family that had an abnormal rate of genetic disease. Scientists observed that males and females alike were affected by the disease but only when their mother was also affected. The children of affected males were all normal. All the children of affected females were affected. Which of the following describes this inheritance pattern?

A. Mitochondrial related

B. Autosomal dominant

C. Autosomal recessive

D. Sex-linked

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22. The detection of mitochondrial mutations is complicated by which of the following?

A. Methods available for analyzing mitochondrial genes

B. Small number of mitochondria in a cell

C. Lack of information about the mitochondrial genome

D. Presence of mutated and normal mitochondria in the same cell

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23. What is indicated by CYP2A6?

A. Cytochrome P-450, subfamily IIA, polypeptide 6

B. Cytochrome P-450, subfamily IIA 6

C. Cytochrome P-450, subfamily 6, polypeptide 2A

D. Cytochrome P-450, polypeptide A6, subfamily II

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24. Mutation in which gene product that catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate can lead to cardiovascular disease and complications in pregnancy?

A. TP53

B. MTHFR

C. F5

D. HLA-H

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25. An (F508del) mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene is responsible for causing which of the following diseases?

A. Idiopathic congenital central hypoventilation syndrome

B. Friedreich ataxia

C. Cystic fibrosis

D. Leber hereditary optic neuropathy

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26. Imprinting is maintained through what modifications?

A. Protein phosphorylation

B. DNA methylation

C. RNA methylation

D. Cytosine deamination

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27. Trinucleotide repeat expansion diseases, such as fragile X syndrome, display what type of inheritance pattern?

A. Phenotypic heterogenicity

B. Regression

C. Anticipation

D. Nonvariable expressivity

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28. What method allows detection of full fragile X chromosomes by capillary electrophoresis?

A. Triplet-primed PCR

B. PCR-RFLP

C. SSP-PCR

D. Multiplex PCR

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29. Which will change with environment and age?

A. Chromosome number

B. Mitochondrial DNA copies

C. DNA methylation patterns

D. Protein phosphorylation

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30. Approximately 40% of mitochondria in a cell harbored the same mutation. What is the name for this condition?

A. Anticipation

B. Rearrangement

C. Homozygosity

D. Heteroplasmy

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