Young: Medical Genetics - Extended Matching Questions

Table of Contents

1. 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: Carrier detection

Options:

1. Clinical examination
2. Enzyme assay
3. Gene tracking / linkage analysis
4. Haemoglobin electrophoresis
5. Mutation analysis

Select the method used for carrier detection in the following situations from the available options.

1

Scenario 1   Cystic fibrosis carrier screening in the general population Choose... Clinical examination Enzyme assay Gene tracking / linkage analysis Haemoglobin electrophoresis Mutation analysis Carriers of cystic fibrosis are entirely healthy with no clinical abnormality. Therefore, the only method for carrier detection is molecular analysis. Carrier screening in the general population is achieved by testing for the most common 25-30 mutations in the relevant community. See Page 149 and 268.Incorrect. See Page 149 and 268.Your answer has been saved.

2

Scenario 2   Cystic fibrosis - mutation unknown Choose... Clinical examination Enzyme assay Gene tracking / linkage analysis Haemoglobin electrophoresis Mutation analysis If the mutation(s) in an affected person cannot be identified, the only approach for carrier detection which can be considered is gene tracking. See Page 92 and 268.Incorrect. See Page 92 and 268.Your answer has been saved.

3

Scenario 3   Duchenne muscular dystrophy Choose... Clinical examination Enzyme assay Gene tracking / linkage analysis Haemoglobin electrophoresis Mutation analysis Creatine kinase assay can be considered as the level is elevated in 2 out of 3 carriers. However, DNA analysis is much more precise, particularly if the mutation in the affected boy is known. Page 111 and 268.Incorrect. See Page 111 and 268.Your answer has been saved.

4

Scenario 4   Beta-thalassaemia carrier screening in the general population Choose... Clinical examination Enzyme assay Gene tracking / linkage analysis Haemoglobin electrophoresis Mutation analysis Beta-thalassaemia shows marked mutational heterogeneity so that carrier screening in the population is approached by measuring haematological parameters such as full blood count and haemoglobin electrophoresis. If the mutation(s) in a family is known, then direct mutation analysis can be used. See Page 161 and 268.Incorrect. See Page 161 and 268.Your answer has been saved.

5

Scenario 5   Tay-Sachs disease carrier screening in the general population Choose... Clinical examination Enzyme assay Gene tracking / linkage analysis Haemoglobin electrophoresis Mutation analysis Tay-Sachs is one of very few inborn errors in which enzyme assay gives a reliable distinction between carriers and non-carriers. This can be augmented by screening for the three common mutations in the Ashkenazi Jewish population. See Pages 148, 215 and 269.Incorrect. See Page Pages 148, 215 and 269.Your answer has been saved.