Young: Medical Genetics - Extended Matching Questions

Table of Contents

1. Chapter 1
   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: Mutations

Options:

1. Dominant negative
2. Gain-of-function
3. Haploinsufficiency
4. Loss-of-function
5. Silent

Select the most appropriate term for the functional effect of the following mutations.

1

Scenario 1   A point mutation that leads to failure of expression of one allele Choose... Dominant negative Gain-of-function Haploinsufficiency Loss-of-function Silent Loss-of-function mutations are a common cause of autosomal recessive disorders including most inborn errors of metabolism. See Page 13.Incorrect. See Page 13.Your answer has been saved.

2

Scenario 2   A point mutation which does not alter the encoded amino acid Choose... Dominant negative Gain-of-function Haploinsufficiency Loss-of-function Silent A silent mutation has no observable effect. These can arise because many amino acids are encoded by several different codons, i.e. the genetic code is 'redundant'. See Page 9.Incorrect. See Page 9.Your answer has been saved.

3

Scenario 3   A deletion that removes an allele and results in a clinical problem Choose... Dominant negative Gain-of-function Haploinsufficiency Loss-of-function Silent Haploinsufficiency refers to an adverse clinical outcome resulting from a deletion/mutation which has a loss-of-function effect. See Page 13.Incorrect. See Page 13.Your answer has been saved.

4

Scenario 4   A mutation which results in different or increased protein activity Choose... Dominant negative Gain-of-function Haploinsufficiency Loss-of-function Silent Gain-of-function can involve increased activity or acquisition of a new activity through formation of a new fusion gene/protein. See Page 13.Incorrect. See Page 13.Your answer has been saved.

5

Scenario 5   A mutation which also results in disturbance of the activity of the normal gene or protein Choose... Dominant negative Gain-of-function Haploinsufficiency Loss-of-function Silent Dominant negative effects are usually seen in conditions associated with a multimeric protein, in which function of the normal gene product is impaired by the abnormal protein product e.g. osteogenesis imperfecta. See Page 13.Incorrect. See Page 13.Your answer has been saved.