Table 2.
Criteria to differentiate thalassaemia major from intermedia at presentation.
| Parameter | Thalassaemia major more likely | Thalassaemia intermedia more likely |
|---|---|---|
| Clinical | ||
| Presentation (years) | <2 | >2 |
| Liver/spleen enlargement | Severe | Moderate to severe |
| Haematological | ||
| Hb level (g/dL) | 6–7 | 7–10 |
| HbF (%) | >50 | 10–50 (may be up to 100%) |
| HbA2 (%) | <3.5 | >3.5 |
| Genetic | ||
| Parents | Both carriers of high HbA2 β-thalassaemia | One or both atypical carriers:
|
| Molecular | ||
| Type of mutation | Severe | Mild/silent |
| Co-inheritance of α-thalassaemia | No | Yes |
| Hereditary persistence of HbF | No | Yes |
| δβ-thalassaemia | No | Yes |
| Gγ Xmn1 polymorphism | No | Yes |
Hb = haemoglobin; HbF = foetal haemoglobin