1. MGD

Question 1

What is amyloidosis?

Answer 1

Misfolding of proteins that forms insoluble forms of normally soluble proteins.

Question 2

What is the result of amyloidosis in the brain?

Answer 2

Alzheimer’s or dementia.

Question 3

What causes sickle cell anaemia?

Answer 3

An autosomal recessive mutation where alanine is replaced with thymine, so valine instead of glutamine - hydrophobic amino acid rather than hydrophilic. This forms hydrophobic knobs and pockets, haemoglobin polymerises to form a sickle shape that gets stuck in microvascualture.

Question 4

What is a sickle cell crisis?

Answer 4

The sickle shape of haemoglobin blocks microvasculature and this causes pain and downstream anaemia.

Question 5

What are sickle cell crises precipitated by?

Answer 5

By lowering O2 availability from smoking, cold, infection.

Question 6

Why do sickle cell haemoglobin lead to anaemia?

Answer 6

The spleen breaks down red blood cells that are faulty so there is haemolytic anaemia.

Question 7

How does sickle cell anaemia cause jaundice?

Answer 7

Haemolytic anaemia as spleen breaks down lots of red blood cels, so there is excess bilirubin released and jaundice.

Question 8

What is a benefit of sickle cell anaemia in some countries?

Answer 8

Provides protection against malaria.

Question 9

What is cystic fibrosis?

Answer 9

An autosomal recessive condition where there is a defective cystic fibrosis transmembrane regulator so impaired Na+/Cl- transport and thickened mucus.

Question 10

What are the complications of cystic fibrosis?

Answer 10

Ciliary escalator is ineffective in the respiratory tract so bacteria isn’t cleared and infections occur. Pancreatitis from blocked pancreatic duct, fat digestion also stopped. Abnormally salty sweat. Vas deferens in males aren’t formed, causing infertility.

Question 11

How is cystic fibrosis managed?

Answer 11

Prophylaxis for lung infection, lipase tablets for fat digestion, bypass vas deferens in males for sperm.

Question 12

What is a-thalassaemia?

Answer 12

Where there is decreased or no a-gobin chains to form haemoglobin.

Question 13

When does a-thalassaemia present and why?

Answer 13

Before birth as foetal haemoglobin (a2y2) needs a-globin chains too, so is affected.

Question 14

What is B-thalassaemia?

Answer 14

Decreased or no B-globin chains to form haemoglobin.

Question 15

When does B-thalassaemia present and why?

Answer 15

After birth as foetal haemoglobin doesn’t have any B-globin chains so isn’t affected.

Question 16

How do thalassaemias cause anaemia?

Answer 16

Stable tetramers can’t form so there is less haemoglobin and decreased oxygen carrying capacity so symptoms of anaemia.

Question 17

What is haemophilia A?

Answer 17

A recessive X linked condition where there is no/reduced factor VIII produced so no clotting.

Question 18

How is haemophilia A treated?

Answer 18

Give recombinant factor VIII and avoid thrombolytics or blood thinners.

Question 19

What is scurvy?

Answer 19

Vitamin C deficiency which means prolyl hydroxylase can’t convert proline to hydroxyproline, this means less H bonds and cross links form so collagen is ‘wobbly’.

Question 20

What is Down’s syndrome?

Answer 20

Trisomy 21 from meiotic division error or Robertsonian translocation.

Question 21

What are the features of Down’s syndrome?

Answer 21

Facial features, heart defects, impaired intelligence, leukaemia, early onset Alzheimer’s.

Question 22

What is Edward’s syndrome?

Answer 22

Trisomy 18 from meiotic division error or Robertsonian translocation.

Question 23

What are the features of Edward’s syndrome?

Answer 23

‘Rockerbottom’ feet, small lower jaw.

Question 24

How long do those with Edward’s syndrome live?

Answer 24

1-2 weeks.

Question 25

What is Patau’s syndrome?

Answer 25

Trisomy 13 from meiotic division error or Robertsonian translocation.

Question 26

What are the features of Patau’s syndrome?

Answer 26

Congenital heart defects, cleft lip.

Question 27

How long do those with Patau’s syndrome live?

Answer 27

Around 2.5 days.

Question 28

What is Turner’s syndrome?

Answer 28

Monosomy X, there is a missing copy of a small autosomal region of the sex chromosome.

Question 29

What are the features of Turner’s syndrome?

Answer 29

Short stature, heart defects, mild learning difficulties, neck webbing, infertility.

Question 30

What is Klinefelter’s syndrome?

Answer 30

XXY, men with an extra X chromosome.

Question 31

What are the features of Klinefelter’s syndrome?

Answer 31

Smaller testes so less testosterone production so lack of male sex characteristics, hypogonadism, infertility.

Question 32

How can Klinefelter’s syndrome be treated?

Answer 32

Testosterone can help with some factors but can’t reverse infertility.