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Child Health Guideline Identifier


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Thalassaemia is often diagnosed following thalassaemia/haemoglobinopathy screening, or incidentally.


  • Children with thalassaemia trait (α or β without co-inheritance of haemoglobinopathies) are asymptomatic and do not require specialist input. Useful resources in a variety of languages can be found on:
  • The low MCV in thalassaemia can be misdiagnosed as iron deficiency. Check Ferritin level to confirm deficiency before commencing iron replacement.
  • When a patient with thalassaemia trait considers family planning in the future, the partner should be screened for thalassaemias/ haemoglobinopathies. This is because co-inheritance of thalassaemia/ haemoglobinopathies in the fetus from both parents can result in a more severe phenotype.
  • Refer the following patients to Paediatric Haematology:
    • Thalassaemia intermedia, thalassaemia major or haemoglobin variants.
    • Co-inheritance of β-thalassaemia and other β-globinopathies ( e.g. HbC, HbE, HbS)

Thalassaemia types


Each person has 4 α-globin genes. α-thalassaemia is most frequently caused by deletions of DNA that involve one or more of the α-globin genes.

Genotype Other names Clinical presentation
 α-/αα 1 gene deletion
Silent carrier
Thalassaemia minima
α-thalassaemia trait 
Hb: Normal/ borderline reduced
MCV: Normal/ borderline reduced
α-/α---/αα 2 gene deletion
α-thalassaemia trait
α-thalassaemia minor 

Note this can be in the:
- trans configuration (α -/α -) more common
- cis configuration (--/αα), less common overall, but relatively more common in Southeast Asians
Hb: Normal/ mildly reduced
MCV: Normal/reduced
α-/-- 3 gene deletion
HbH disease
α-thalassaemia intermedia
(in some cases, this may be due to an alpha chain variant rather than deletion)
Variable, mostly non-transfusion dependent
Hb: Moderately reduced
MCV: Markedly reduced

 --/-- 4 gene deletion
Hb Bart disease
Hydrops fetalis
α-thalassaemia major 
Incompatible with extra-uterine life, transfusion dependent 


The mutations in β-thalassaemia is much more heterogenous. Over 200 mutations have been described.

Genotype Clinical presentation
β-thalassaemia minor Asymptomatic
Hb: Normal/ mildly reduced
MCV: Markedly reduced
β-thalassaemia intermedia  Intermediate phenotype, may require transfusions
Anaemia can be aggravated by infection, onset of puberty, development of splenomegaly/ hypersplenism 
Hb: Normal/ mildly reduced
MCV: Markedly reduced
β-thalassaemia major Transfusion dependent
May require splenectomy
If untreated, lead to symptoms of anaemia, and bony deformities affecting growth and development 
Endocrine abnormalities due to iron overload
Hb: Markedly reduced
MCV: Markedly reduced

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Document Control

  • Date last published: 01 November 2017
  • Document type: Clinical Guideline
  • Services responsible: Paediatric Haematology/Oncology
  • Author(s): Lochie Teague
  • Owner: Lochie Teague
  • Editor: Greg Williams
  • Review frequency: 2 years

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