Review Note

A 23-year-old Asian man presents to his GP complaining of shortness of breath following exercise. He has always been a little unfit and decided to start going to the gym but noticed that even after 4 weeks he is still quite short of breath. He denies any coughing or wheezing and on examination you notice mild pallor but the patient says he has always been slightly pale in colour. Investigation results are given below:
Haemoglobin 12 g/dL
MCV 70 fL
Serum iron 14umol/L
Ferritin 60 ug/L
Transferrin saturation 35 percent
Mean cell haemoglobin 22 pg Haemoglobin electrophoresis HbA2 increased
The most likely diagnosis is:

• ⍺ thalassaemia trait
• Anaemia of chronic disease 
• ß thalassaemia trait
• Haemoglobin H disease
• Iron deficiency anaemia
  

ß thalassaemia trait

This patient is suffering from a microcytic anaemia ( MCV <80 ) with normal iron parameters. The differential diagnoses of a microcytic anaemia include iron deficiency anaemia, anaemia of chronic disease and thalassaemia disease. The normal iron parameters eliminate iron deficiency anaemia while serum iron tends to be low and ferritin tends to be high in an anaemia of chronic disease. This leaves a disease of thalassaemia, a thalassaemia trait usually results from gene deletion on chromosome 16 (B thalassaemia is coded on chromosome 11). There are two a globin genes from each parent so that adults have a total of four a globin genes. A single or double deletion causes a mild, usually asymptomatic anaemia known as a+ and a- disease, respectively.
Haemoglobin H disease involves three a deletions causing a significant anaemia beginning in childhood with target cells, Heinz bodies and splenogmegaly. In B thalassaemia trait points to mutations of a single ß globin gene allele. This causes a mild microcytic anaemia, electrophoresis shows an increased haemoglobin A2.

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