Introduction to haemoglobinopathy

Question 1

What are the 3 main forms of haemoglobin?

Answer 1

• HbA - 2a chains 2ß chains
• HbA2 - 2a chains 2∂ chains
• HbF - 2a chains 2gamma chains

Question 2

Which chromosome are alpha haemoglobin genes found on?

Answer 2

Chromosome 16

Question 3

Which chromosome are beta haemoglobin genes found on?

Answer 3

Chromosome 11

Question 4

How many alpha genes are found in each cell?

Answer 4

4 - 2 on each chromosome

Question 5

How many beta genes are found in each cell?

Answer 5

2 - 1 on each chromosome

Question 6

What is the most prominent globin chain during the first 3 months of foetal development?

Answer 6

Epsilon

Question 7

What are the most prominent globin chain between 3 months of foetal development and birth?

Answer 7

Alpha and Gamma

Question 8

When do beta chains start to take over from gamma chains during development?

Answer 8

At birth

Question 9

When are adult levels of ß-chains found in children?

Answer 9

Between 6 and 12 months (So problems with ß-chains will present then)

Question 10

What are haemoglobinopathies?

Answer 10

They are hereditary conditions affecting globin chain synthesis

They are the result of hundreds of mutations and mostly behave as autosomal recessive disorders

Question 11

What are the 2 main groups of haemoglobinopathy?

Answer 11

Thalassaemias - Decreased globin chain synthesis

Structural haemoglobin variants

Question 12

How are haemoglobinopathies diagnosed?

Answer 12

• FBC
• Hb
• Blood film
• Ethnic origin
• High performance liquid chromatography (HPLC) or electrophoresis§

Question 13

What is the purpose of HPLC or electrophoresis?

Answer 13

HPLC or electrophoresis allows for the quantifying of haemoglobins present and identification of abnormal haemoglobins