Session 17-Genetics In Medicine

Question 1

What are the symptoms of sickle cell anaemia (SCA)? (3)

Answer 1

Anaemia
Fever
Severe pain

Question 2

Which single DNA mutation causes SCA?

Answer 2

A to T in the beta-globin gene

Question 3

How does the single DNA mutation cause a change in the beta-globin protein?

Answer 3

Position 6 in the AA chain from Glu to Val

Question 4

True or false: only one copy of beta-globin needs to be mutated to cause SCA

Answer 4

FALSE-both have to because it is an autosomal recessive disorder

Question 5

True or false: individuals who are heterozygous for SCA (sickle cell trait) are resistant to malaria

Answer 5

TRUE

Question 6

What is epigenetics?

Answer 6

Complex web of gene regulation

Question 7

True or false: foetal gamma globin is turned off after birth and adult beta globin is turned on

Answer 7

TRUE

Question 8

Can gamma globin be kept switched on?

Answer 8

Yes, it has no impact on health but would prevent SCA

Question 9

Which protein binds to DNA and switches off the gamma globin gene?

Answer 9

Protein BCL11A (repressor)

Question 10

What does HSPC stand for and what can it be used in?

Answer 10

Haemopoietic stem and progenitor cells

Used in gene editing therapy for SCA

Question 11

What is Huntington’s disease (HD)?

Answer 11

Inherited neurodegenerative disease

Question 12

What are the symptoms of HD? (4)

Answer 12

Seizures
Abnormal gait
Personality change
Dementia

Question 13

True or false: the mutation causing HD is a short tandem repeat (STR) of CGA

Answer 13

FALSE - it is a STR of CAG

Question 14

True or false: HD is autosomal recessive

Answer 14

FALSE - autosomal dominant

Question 15

What is the age of onset of HD?

Answer 15

40-50

Question 16

True or false: from generation to generation, age of onset of HD becomes earlier and symptoms become more severe

Answer 16

TRUE

Question 17

How is age of onset of HD affected by CAG repeat length?

Answer 17

Negative correlation - as CAG repeat length increases, age of onset decreases but still lots of variation

Question 18

What influences age of onset of HD?

Answer 18

Multifactorial - CAG repeat length as well as other genetic factors (one on chromosome 8 and two on chromosome 15)

Question 19

What causes developmental disorders?

Answer 19

Environment (infection, maternal alcohol etc)

New mutation in gene

Question 20

True or false: developmental disorders can be found by sequencing the exome (exons of genome)

Answer 20

TRUE