Thalassaemia

Question 1

What is thalassaemia and where is it most common?

Answer 1

1. Genetic disease of unbalanced Hb synthesis, under/no production of Beta globin chain. Unmatched globins precipitate, damaging RBC membranes, causing haemolysis while still in the marrow. Homozygous worse than heterozygous.
2. Mediterranean to the Far-East.

Question 2

What is this describing?

B/B+ heterozygous. Carrier state, asymptomatic. Mild, well tolerated anaemia which may worsen in pregnancy.

Answer 2

B thalassaemia minor/trait

Question 3

What is this describing?
Moderate anaemia but not requiring transfusion, may be splenomegaly. Variety of causes, can progress from mild disease or be precipitated by another haemoglobinopathy.

Answer 3

B thalassaemia intermedia

Question 4

When and how does beta thalassaemia major present?

Answer 4

1. In 1st year of life
2. Severe anaemia and failure to thrive, skull bossing and hepatosplenomegaly (extramedullary haematopoiesis), osteopenia.

Question 5

What is the treatment for beta thalassaemia major and what does it cause?

Answer 5

1. Lifelong blood transfusions
2. Iron overload (hypogonadism, hypothyroidism, diabetes and hypocalcaemia), progressive endocrine failure, liver disease, and cardiac toxicity.

Question 6

What is the treatment for B thalassaemia generally?

Answer 6

1. Promote fitness, healthy diet, folate supplements.
2. Regular (2-4 weekly) lifelong transfusion to keep Hb >90g/L to suppress ineffective extramedullary haematopoiesis and allow normal growth.
3. Iron chelators and hormone replacement in iron overload.
4. Splenectomy if hypersplenism persists with increasing transfusions.
5. Histocompatibility marrow transplant can offer chance of cure.

Question 7

What are the types of alpha thalassaemia?

Answer 7

1. 1 gene deleted - clinically normal
2. 2 genes deleted - asymptomatic carrier with low MCV
3. 3 genes deleted - moderate anaemia, hepatosplenomegaly, leg ulcers, jaundice.
4. All 4 genes deleted - death in utero