Week 2 Lecture 1: Haemoglobinopathy

Question 1

Where are the α-globin genes located?

Answer 1

Two α-globin genes are located on chromosome 16.

Question 2

Where is the β-globin gene located?

Answer 2

The β-globin gene is located on the short arm of chromosome 11.

Question 3

How are globin genes regulated?

Answer 3

Globin genes are developmentally regulated.

Question 4

What factors affect the production of haemoglobin?

Answer 4

Production of haemoglobin is affected by globin chain synthesis, Fe levels, and porphyrin levels.

Question 5

What is the normal range for haemoglobin in males (g/dL)?

Answer 5

13.5–17.5 g/dL

Question 6

What is the normal range for haemoglobin in females (g/dL)?

Answer 6

11.5–15.5 g/dL

Question 7

What is the normal range for haematocrit in males (%)?

Answer 7

40–52%

Question 8

What is the normal range for haematocrit in females (%)?

Answer 8

36–48%

Question 9

What is the normal range for red cell count in males (×10^12/L)?

Answer 9

4.5–6.5 ×10^12/L

Question 10

What is the normal range for red cell count in females (×10^12/L)?

Answer 10

3.9–5.6 ×10^12/L

Question 11

What is the normal range for mean cell haemoglobin (MCH) in males (pg)?

Answer 11

27–34 pg

Question 12

What is the normal range for mean cell haemoglobin (MCH) in females (pg)?

Answer 12

27–34 pg

Question 13

What is the normal range for mean cell volume (MCV) in males (fL)?

Answer 13

80–95 fL

Question 14

What is the normal range for mean cell volume (MCV) in females (fL)?

Answer 14

80–95 fL

Question 15

What is the normal range for mean cell haemoglobin concentration (MCHC) in males (g/dL)?

Answer 15

30–35 g/dL

Question 16

What is the normal range for mean cell haemoglobin concentration (MCHC) in females (g/dL)?

Answer 16

30–35 g/dL

Question 17

What is the normal range for reticulocyte count (×10^9/L)?

Answer 17

50–150 ×10^9/L

Question 18

What are haemoglobinopathies?

Answer 18

Inherited single-gene disorders causing defects in globin chain structure, often manifesting as haemolytic anaemia.

Question 19

What are thalassaemias?

Answer 19

Autosomal recessive blood disorders causing defects in α or β globin chain synthesis, often manifesting as hypochromic microcytic anaemia.

Question 20

What is the normal genotype for haemoglobin?

Answer 20

The ‘normal’ genotype is AA, representing one normal Hb A from each parent.

Question 21

What percentage of haemoglobin is Hb A?

Answer 21

Hb A ~ 96%

Question 22

What percentage of haemoglobin is Hb A2?

Answer 22

Hb A2 ~ 3%

Question 23

What percentage of haemoglobin is Hb F?

Answer 23

Hb F ~ 1%

Question 24

What are some laboratory tests for haemoglobin?

Answer 24

Wet prep and sickle solubility, haemoglobin electrophoresis, immunoassays, high performance liquid chromatography, and DNA analysis.

Question 25

What is the wet prep method?

Answer 25

EDTA whole blood is dropped onto a slide with sodium metabisulfite, then examined microscopically after incubation.

Question 26

What is the sickle solubility test?

Answer 26

Saponin and sodium dithionite are added to whole blood and mixed with phosphate buffer; sickle haemoglobin becomes opaque against a line test card.

Question 27

What is haemoglobin electrophoresis used for?

Answer 27

It is used to identify and quantify both normal and variant haemoglobins.

Question 28

What are immunoassays used for in haemoglobin testing?

Answer 28

ELISA of Hb F and flow cytometry.

Question 29

What is HPLC used for?

Answer 29

High Performance Liquid Chromatography is used to identify and quantify more complicated haemoglobins.

Question 30

What is the purpose of DNA analysis in haemoglobin testing?

Answer 30

It is used for confirmation of serious haemoglobin variants in reference laboratories.