thalasaemia

Question 1

what happens in thalassaemia?

Answer 1

Thalassaemia is related to a genetic defect in the protein chains that make up haemoglobin.

Normal haemoglobin consists of 2 alpha and 2 beta-globin chains.

Defects in alpha-globin chains leads to alpha thalassaemia.

Question 2

what is the inheritance pattern of thalassaemia?

Answer 2

autosomal recessive

Question 3

what facial features will someone with thalasaemia have and why?

Answer 3

The bone marrow expands to produce extra red blood cells to compensate for the chronic anaemia.

This causes a susceptibility to fractures and prominent features such as a pronounced forehead and malar eminences (cheekbones).

Question 4

which investigations would you preform for diagnosis and what would the results be?

Answer 4

Full blood count shows a microcytic anaemia.

Haemoglobin electrophoresis is used to diagnose globin abnormalities.

DNA testing can be used to look for the genetic abnormality

Question 5

why might there be iron overload in thalasaemia?

Answer 5

Iron overload occurs in thalassaemia as a result of faulty creation of red blood cells, recurrent transfusions and increased absorption of iron in response to the anaemia.

Question 6

what are the risks and management of iron overload?

Answer 6

Management involves limiting transfusions and iron chelation.

Iron overload in thalassaemia causes effects similar to haemochromatosis:

Fatigue
Liver cirrhosis
Infertility and impotence
Heart failure
Arthritis
Diabetes
Osteoporosis and joint pain

Question 7

which chromosome is responsible for alpha thalasaemia?

Answer 7

chr16

Question 8

what is the treatment for alpha thalasaemia?

Answer 8

Monitoring the full blood count
Monitoring for complications
Blood transfusions
Splenectomy may be performed
Bone marrow transplant can be curative

Question 9

which gene is responsible for beta thalasaemia?

Answer 9

chr 11

Question 10

what are the different types of beta thalasemia?

Answer 10

Thalassaemia minor
Thalassaemia intermedia
Thalassaemia major

Question 11

what is minor B thalasaemia?

Answer 11

They have one abnormal and one normal gene.

Thalassaemia minor causes a mild microcytic anaemia and usually patients only require monitoring and no active treatment.

Question 12

what is thalassaemia intermedia?

Answer 12

. This can be either two defective genes or one defective gene and one deletion gene.

Thalassaemia intermedica causes a more significant microcytic anaemia and patients require monitoring and occasional blood transfusions.

If they need more transfusions they may require iron chelation to prevent iron overload.

Question 13

what is beta thalasaemia major?

Answer 13

Patients with beta thalassaemia major are homozygous for the deletion genes. They have no functioning beta-globin genes at all. This is the most severe form and usually presents with severe anaemia and failure to thrive in early childhood.

Thalassaemia major causes:

Severe microcytic anaemia
Splenomegaly
Bone deformities

Management involves regular transfusions, iron chelation and splenectomy. Bone marrow transplant can potentially be curative.