Thalassaemia
Thalassaemia is often diagnosed following thalassaemia/haemoglobinopathy screening, or incidentally.
Thalassaemia is often diagnosed following thalassaemia/haemoglobinopathy screening, or incidentally.
Management
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: www.thalassemia.org
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
α-Thalassaemia
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 |
Asymptomatic 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 |
Asymptomatic 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 |
β-Thalassaemia
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 |