Young: Medical Genetics - Extended Matching Questions

Table of Contents

1. Chapter 1
   1. Question 1
   2. Question 2
2. Chapter 2
   1. Question 1
   2. Question 2
3. Chapter 3
   1. Question 1
   2. Question 2
4. Chapter 4
   1. Question 1
   2. Question 2
5. Chapter 5
   1. Question 1
   2. Question 2
6. Chapter 6
   1. Question 1
   2. Question 2
7. Chapter 7
   1. Question 1
   2. Question 2
8. Chapter 8
   1. Question 1
   2. Question 2
9. Chapter 9
   1. Question 1
   2. Question 2
10. Chapter 10
    1. Question 1
    2. Question 2
11. Chapter 11
    1. Question 1
    2. Question 2
12. Chapter 12
    1. Question 1
    2. Question 2
13. Chapter 13
    1. Question 1
    2. Question 2
14. Chapter 14
    1. Question 1
    2. Question 2

Question 2

Instructions: Each group of extended matching questions consists of lettered options followed by a list of numbered problems/questions. For each numbered problem/question select the one lettered option that is most closely answers the question. You can use the lettered options once, more than once, or not at all.

Theme: Chromosome rearrangements

Options:

1. Deletion
2. Insertion
3. Paracentric inversion
4. Pericentric inversion
5. Balanced reciprocal translocation
6. Unbalanced reciprocal translocation
7. Robertsonian translocation
8. Ring chromosome
9. Isochromosome

For each of the following chromosome rearrangements select the correct description.

1

Scenario 1   A point mutation that leads to failure of expression of one allele Choose... Deletion Insertion Paracentric inversion Pericentric inversion Balanced reciprocal translocation Unbalanced reciprocal translocation Robertsonian translocation Ring chromosome Isochromosome An isochromosome consists of two short arms or two long arms and is formed by abnormal division of the centromere at meiosis. See Page 43.Incorrect. See Page 43.Your answer has been saved.

2

Scenario 2   A chromosome which contains a segment which has turned upside down and includes the centromere Choose... Deletion Insertion Paracentric inversion Pericentric inversion Balanced reciprocal translocation Unbalanced reciprocal translocation Robertsonian translocation Ring chromosome Isochromosome A pericentric inversion includes the centromere whereas a paracentric inversion involves only one arm of the chromosome. See Page 42.Incorrect. See Page 42.Your answer has been saved.

3

Scenario 3   A chromosome which is made up of the long arms of two acrocentric chromosomes which have fused at their centromeres with loss of the short arms Choose... Deletion Insertion Paracentric inversion Pericentric inversion Balanced reciprocal translocation Unbalanced reciprocal translocation Robertsonian translocation Ring chromosome Isochromosome A Robertsonian translocation is a particular type of translocation formed by fusion of two acrocentric chromosomes at their centromeres. This can sometimes account for a positive family history of Down syndrome. See Page 40 and 44.Incorrect. See Page 44.Your answer has been saved.

4

Scenario 4   A chromosome that has lost material from both ends with fusion of the 'sticky' ends Choose... Deletion Insertion Paracentric inversion Pericentric inversion Balanced reciprocal translocation Unbalanced reciprocal translocation Robertsonian translocation Ring chromosome Isochromosome The sticky ends fuse to form a ring shaped chromosome. This is an unbalanced rearrangement as there is loss of material from both ends of the chromosome. See Page 41.Incorrect. See Page 41.Your answer has been saved.

5

Scenario 5   Two chromosomes that have exchanged segments without loss or gain of any material Choose... Deletion Insertion Paracentric inversion Pericentric inversion Balanced reciprocal translocation Unbalanced reciprocal translocation Robertsonian translocation Ring chromosome Isochromosome This rearrangement is balanced because the two chromosomes, although rearranged, still contain the correct amount of chromosome material. However if a child inherits only one of the rearranged chromosomes, then this will be an unbalanced rearrangement and the child will usually have serious developmental abnormalities. See Pages 39 and 44.Incorrect. See Page 39.Your answer has been saved.