Severity of thalassaemia | Type of thalassaemia |
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Thalassaemia minor (or asymptomatic carriership) | - Alpha globin gene defect in one or two of four alleles
- Beta globin gene defect causing a mild form of the disease in one of two alleles
|
Thalassaemia intermedia | - HbH disease
- Some heterozygous carriers of the beta-0 mutation
- Most combination thalassaemias
|
Thalassaemia major | - Homozygous carriers of beta globin mutations; symptoms from infancy
- Some patients with combination thalassaemia or HbH disease; symptoms from teenage or adulthood
|