A cause of microcytic anaemia
- Inherited defect causing reduced production of alpha-globin
- Problems may arise before birth as fetal Hb requires alpha chains.
- Manifestations depend on how many of the 4 alpha-globin genes per cell are absent
- Seen more so in African and Far eastern populations
- In adults the Hb is composed of 2 alpha chains and 2 Beta chains
- In Alpha Thalassaemia there is a defect in making alpha chains
- There are 4 genes that make alpha-globin per cell
- Four gene deletion - This is not compatible with life and death occurs
in utero. A cause of stillbirth in asian countries.
- Three gene deletion = HbH disease leads to Moderate
anaemia (8-10 g/dl) microcytic and hypochromic with splenomegaly, leg
ulcers, jaundice. Can worsen with pregnancy or infection.
- Two gene deletion - no anaemia or splenomegaly only some microcytosis
- One gene deletion - asymptomatic silent
- Mental learning and cognitive issues may be seen in some rare variants of the
- FBC: Microcytic anaemia HbH disease 8-10 g/dl
- Blood film: Microcytosis, anisocytosis, poikilocytosis
- Reticulocytes, LDH, Haptoglobins: Evidence of haemolysis
- HbH - Transfusions - not usually needed except pregnant or surgery
- Give folate especially during and before pregnancy
- Genetic counselling