Thalassaemia

Question 1

What do doctors often mistake thalassaemia trait for?

Answer 1

iron deficiency anaemia
- this leads to them incorrectly prescribing iron supplements that have no effect

Question 2

What is alpha thalassaemia?

Answer 2

people who do not produce enough alpha globin protein chains
individuals who have one or two abnormal alpha globin genes have alpha thalassaemia trait

Question 3

how many genes make up alpha globin?

Answer 3

4, two on each strand of chromosome 16

Question 4

What is a silent carrier of alpha thalassaemia trait?

Answer 4

one abnormal alpha globin gene

Question 5

What are the symptoms experienced by a silent carrier of alpha thalassaemia?

Answer 5

no health problems, because the lack of alpha globin protein is so small that there is no anaemia

Question 6

Why is it called a silent carrier?

Answer 6

because of how difficult it is to detect

Question 7

How is a silent carrier of alpha thalassaemia “diagnosed”?

Answer 7

Silent carrier state is “diagnosed” by deduction when an apparently normal individual has a child with haemoglobin H disease or alpha thalassaemia minor

It can also be diagnosed by special DNA testing

Question 8

What is alpha thalassaemia trait?

Answer 8

2 abnormal alpha globin genes
- the two genes can be on the same chromosome or on each chromosome in the pair
- 2 of the 4 alpha globin genes are missing or defective
- the lack of alpha globin protein is somewhat greater

Question 9

What are the physiological occurrences of thalassaemia trait?

Answer 9

smaller RBCs and mild anaemia
But they do not experience symptoms

Question 10

What is haemoglobin H disease?

Answer 10

where 3 of the 4 alpha globin genes are abnormal

Question 11

What happens in haemoglobin H disease?

Answer 11

the lack of alpha protein is great enough to cause moderate to severe anaemia and may cause severe health problems such as…
an enlarged spleen
bone deformities
fatigue

Question 12

What is it called when all 4 alpha globin genes are abnormal?

Answer 12

Hydrops fetalis/ alpha thalassaemia major

Question 13

What happens with alpha thalassaemia major?

Answer 13

most individuals die before or shortly after birth

In some extreme rare cases, in utero blood transfusions have allowed the birth of these children who then require lifelong blood transfusions and extensive ongoing medical care

Question 14

What makes beta globin?

Answer 14

2 genes, one on each chromosome 11

Question 15

What is it called when someone only has 1 abnormal beta globin gene?

Answer 15

beta thalassaemia trait aka beta thalassaemia minor

Question 16

Do people with beta thalassaemia minor experience symptoms?

Answer 16

No, no health problems other than mild anaemia

Question 17

What is it called when someone inherits 2 abnormal beta globin genes in the most severe form?

Answer 17

beta thalassaemia major or Cooley’s anaemia

Question 18

What happens in beta thalassaemia major?

Answer 18

life-threatening anaemia that requires regular blood transfusions and extensive ongoing medical care

Question 19

What do lifelong transfusions lead to?

Answer 19

iron overload

Question 20

How do you treat iron overload?

Answer 20

chelation therapy to prevent early death from organ failure

Question 21

What is it called when you inherit 2 abnormal beta globin genes, in a milder form?

Answer 21

Beta thalassaemia intermedia

Question 22

What happens in beta thalassaemia intermedia?

Answer 22

the lack of beta globin in the haemoglobin causes a moderately severe anaemia and significant health problems including…
bone deformities and enlarged spleen

Question 23

When is it classed as beta thalassaemia major?

Answer 23

when blood transfusions are required

Question 24

What “variants” can the beta thalassaemia trait combine with?

Answer 24

E beta thalassaemia
sickle cell thalassaemia

Question 25

What happens when it combines with E beta thalassaemia?

Answer 25

it is a moderately severe anaemia that has similar symptoms to beta thalassaemia intermedia but on occasion may be as severe as thalassaemia major.

haemoglobin E trait is one of the most common abnormal hemoglobins. it is usually found in people of southeast asian ancestry.

Question 26

What happens when it combines with sickle cell?

Answer 26

The severity of the condition varies according to the amount of normal beta globin produced by the beta globin gene.

When no beta globin is produced by the beta globin gene, the condition is almost identical to sickle cell.

When some beta globin is produced the condition is less severe.

haemoglobin S trait is commonly found in people of African or Mediterranean ancestry.