Medical Genetics Test Bank Chapter 10 (Developmental Genetics)

1- Thus far, two genes have been found that can cause autosomal dominant breast cancer (one on chromosome 13 and one on chromosome 17). This is best described as an example of:?

A) Linkage
B) Allelic heterogeneity
C) Synteny
D) Linkage disequilibrium
E) Locus heterogeneity

... Answer is E)

2- The in situ hybridization technique does not involve the use of?

A) Cloned probes
B) X-ray film
C) Complementary base pairing
D) Gene product expression
E) Metaphase chromosomes

... Answer is D)

3- The Utah Mormons have been the subjects of numerous genetic studies. Which of the following is not true of this population? ?

A) Inbreeding rates are low
B) The prevalence rates of PKU and cystic fibrosis are high, relative to other Caucasian populations
C) Inbreeding rates have declined through time
D) Genetically, the population still resembles populations derived from northern Europe
E) Some cases of multiple consanguinity have been observed

... Answer is B)

4- Which of the following is not true of linkage disequilibrium??

A) It is a type of association that involves alleles at linked loci
B) It can be caused by natural selection
C) It can be caused by a disease mutation that has arisen recently on a chromosome containing a specific marker allele
D) It becomes nondetectable after one generation of random mating
E) It can be used to map genes

... Answer is D)

5- For which of the following diseases would you expect to observe the highest heritability?

A) Neural tube defects
B) Measles
C) Cleft lip/palate
D) Schizophrenia
E) Cystic fibrosis

... Answer is E)

6- The quantitative trait locus method does not typically involve?

A) Estimation of heritability
B) Linkage analysis
C) DNA sequence homology between humans and animal models
D) Breeding experiments
E) Gene cloning

... Answer is A)

7- Which of the following is least likely to be seen in highly heritable subsets of multifactorial diseases??

A) Early age of onset
B) Relatively severe presentation of the disorder
C) Recurrence risk is higher in siblings of probands than in more remote relatives
D) Bilateral presentation (when there is laterality)
E) Recurrence risk in siblings is higher when the proband is affected later in life

... Answer is E)

8- A multifactorial disease has a prevalence of 1/500 in females and 1/1,000 in males. You are evaluating families in which a parent is affected. Under a sex-specific threshold model, which parent-offspring combination would you expect to yield the highest risk for the offspring??

A) Father-son
B) Father-daughter
C) Mother-son
D) Mother-daughter
E) A and B are equal

... Answer is B)

9- Which of the following are not part of the adaptive immune system??

A) T-cell receptors
B) Immunoglobulins
C) Natural Killer cells
D) MHC class I molecules
E) MHC class II molecules

... Answer is C)

10- Which of the following characteristics are not shared by T-cell receptors and B-cell receptors??

A) Multiple germline genes that can encode the joining region
B) Junctional diversity
C) Somatic recombination
D) Multiple germline genes that can encode the variable region
E) Secretion from the cell surface into the systemic circulation

... Answer is E)

11- Which of the following factors are not part of the regulatory process that helps to prevent uncontrolled cell growth leading to cancer??

A) Signal transduction molecules
B) Growth factors
C) Growth factor receptors
D) Nuclear transcription factors
E) DNA polymerase

... Answer is E)

12- A large proportion of the mutations leading to adenomatous polyposis coli (APC) are?

A) Missense mutations
B) Nonsense mutations
C) Splice site mutations
D) In-frame deletions
E) Expanded trinucleotide repeats

... Answer is B)

13- Which of the following offers a long-term (> 1 year or so) gene therapy treatment??

A) Retroviral vectors inserted into bone marrow stem cells
B) Adenovirus vectors
C) Retroviral vectors inserted into peripheral lymphocytes
D) All of the above
E) None of the above

... Answer is A)

14- Which of the following is not true of genetic diagnosis using a linked marker??

A) The location of the disease gene does not need to be known
B) Family members must be studied
C) Uninformative matings are sometimes a problem
D) Crossover events may reduce the accuracy of diagnosis
E) Becomes impractical when there is a large number of different disease-causing mutations at a locus.

... Answer is E)

15- Which of the following systems would be most important in determining maternalfetal compatibility? ?

A) Rh blood group
B) ABO blood group
C) MHC class I molecules
D) MHC class II molecules
E) MHC class III molecules

... Answer is A)

16- Down syndrome?

A) Lysosomal storage disorder
B) Elevated amniotic alpha-fetoprotein
C) Decreased amniotic alpha-fetoprotein
D) Vocal and motor tics
E) Rhodopsin mutations

... Answer is C)

17- Tourette syndrome?

A) Lysosomal storage disorder
B) Elevated amniotic alpha-fetoprotein
C) Decreased amniotic alpha-fetoprotein
D) Vocal and motor tics
E) Rhodopsin mutations

... Answer is D)

18- Spina bifida?

A) Lysosomal storage disorder
B) Elevated amniotic alpha-fetoprotein
C) Decreased amniotic alpha-fetoprotein
D) Vocal and motor tics
E) Rhodopsin mutations

... Answer is B)

19- Retinitis pigmentosa?

A) Lysosomal storage disorder
B) Elevated amniotic alpha-fetoprotein
C) Decreased amniotic alpha-fetoprotein
D) Vocal and motor tics
E) Rhodopsin mutations

... Answer is E)

20- Tay-Sachs disease?

A) Lysosomal storage disorder
B) Elevated amniotic alpha-fetoprotein
C) Decreased amniotic alpha-fetoprotein
D) Vocal and motor tics
E) Rhodopsin mutations

... Answer is A)

21- Anencephaly can be diagnosed by?

A) Chorionic villus sampling
B) Amniocentesis
C) In vitro fertilization diagnosis
D) Ultrasonography
E) B and D

... Answer is E)

22- Variations in the angiotensinogen gene are associated with pre-eclampsia. Which of the following is not explained by this statement??

A) Angiotensinogen mutations can cause pre-eclampsia
B) he angiotensinogen gene is in linkage disequilibrium with a gene that causes preeclampsia
C) The angiotensinogen gene may be part of the genetic "background" that causes preeclampsia
D) The fetal genotype, not the maternal genotype, is predictive of pre-eclampsia
E) B and D

... Answer is D)

23- The PCR technique involves the use of?

A) Synthesized oligonucleotide primers
B) Cloned probes
C) DNA polymerase
D) Metaphase chromosomes
E) A and C

... Answer is E)

24- Which of the following will not cause triploidy?

A) Fusion of an egg and polar body with subsequent fertilization by sperm cell
B) Meiotic failure, producing diploid sperm or egg
C) Dispermy
D) Mitotic failure in the early embryo
E) B and D

... Answer is D)

25- Which of the following can be used to determine the physical locations of genes??

A) Radioactive in situ hybridization
B) Fluorescence in situ hybridization
C) Somatic cell hybridization
D) Cytogenetic analysis of deletions and translocations
E) All of the above

... Answer is E)

26- Which of the following is not true about class I and class II MHC molecules??

A) Both present foreign antigens to T-cell receptors
B) Both undergo somatic recombination to produce diversity
C) Are both encoded by highly polymorphic genes
D) Are both located on the surfaces of all nucleated cells
E) B and D

... Answer is E)

27- Which of the following represent advantages of chorionic villus sampling (CVS) over amniocentesis??

A) Placental mosaicism is less common in CVS
B) CVS detects a larger range of genetic disorders than does amniocentesis
C) CVS has a lower fetal loss rate
D) CVS can be performed earlier in the pregnancy
E) B and D

... Answer is D)

28- Difficulties encountered in somatic cell gene therapy using retroviral vectors include all of the following except?

A) Inability to infect nondividing cells
B) Limitation on the size of the inserted gene
C) Transient and low-level gene expression
D) Inability to integrate into the host's DNA
E) C and D

... Answer is D)

29- Disadvantages of using allele-specific oligonucleotides for genetic diagnosis include:?

A) Part of the gene's DNA sequence must be known
B) Other family members affected with the disorder must also be studied
C) A different oligonucleotide must be used for each disease-causing mutation
D) The mutation must occur at a restriction site
E) A and C

... Answer is E)

30- The quantitative trait locus technique has been used in attempts to find genes for all of the following except?

A) Diabetes
B) Obesity
C) Hypertension
D) Schizophrenia
E) A and C

... Answer is D)

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