Genetic Disease

Question 1

What is linkage?

Answer 1

The principal that genes which are close together tend not to get split apart

Question 2

What are the 2 types of genetic disease?

Answer 2

• Germline
• Somatic

Question 3

What are the types of germline disease?

Answer 3

• Chromosomal defects
• Monogenic disorders
• Polygenic disorders

Question 4

What are the 3 ways prenatal testing can be carried out?

Answer 4

• Aminocentesis
• Chorionic Villus Sample
• Maternal Blood Test

Question 5

How does aminocentesis work?

Answer 5

Aminotic fluid contains foetal cells which are cultured

Question 6

What are the downsides to aminocentisis?

Answer 6

• only get 1 chance
• Increases risk of miscarriage

Question 7

What is a chorionic villus sample?

Answer 7

Tissue that will make placenta is removed and analysed

Question 8

What is the advantage of the chorionic villus sample?

Answer 8

It can be analysed more quickly than aminocentisis

Question 9

What is the disadvantage of the chorionic villus sample?

Answer 9

It increases risk of miscarriage

Question 10

What are the disadvantages of maternal blood test?

Answer 10

Currently not very accurate

Question 11

How does a maternal blood test for prenatal testing work?

Answer 11

Foetal DNA can be detected in maternal blood, this can be used to detect trisomies

Question 12

What are the 2 types of postnatal testing?

Answer 12

• Neonatal testing
• Adult testing

Question 13

How is neonatal testing carried out?

Answer 13

Heel prick test

Question 14

Give an example of a disease which is tested for by heel prick tests

Answer 14

Phenylketonuria

Question 15

What is the advantage of neonatal testing?

Answer 15

It allows for fast intervention

Question 16

Why is adult genetic testing done?

Answer 16

For carrier detection and for diagnosis of late onset disorders

Question 17

What are the methods used for genetic testing?

Answer 17

• chromosome analysis
• molecular analysis

Question 18

What can cause chromosomal defects?

Answer 18

• Abnormal separation
• Abnormal crossing over

Question 19

What are the types of chromosomal defects?

Answer 19

• numerical
• structural
• chromosome translocation

Question 20

What is turner syndrome?

Answer 20

When a woman has only one x chromosome

Question 21

What is Klinefelter syndrome?

Answer 21

Men who have XXY chromosomes

Question 22

What is reverse genetics?

Answer 22

Using the genotype to find the phenotype

Question 23

How can the location of a gene responsible for causing a disease be found?

Answer 23

• Chromosomal defects
• Linkage analysis

Question 24

How does linkage analysis occur?

Answer 24

Use markers to find differences between individual genomes

Question 25

Give an example of a disease due to repeat expansions

Answer 25

Huntingdons disease

Question 26

What methods are used for identifying genes involved in polygenic disorders?

Answer 26

• candidate genes
• linkage analysis
• association studies

Question 27

What is mosaicism?

Answer 27

When a proportion of cells in the body carry a genetic defect

Question 28

Are tumour suppressor genes dominant or recessive?

Answer 28

Recessive

Question 29

Are oncogenes dominant or recessive?

Answer 29

Dominant