Identification and key management of non-transfusion-dependent thalassaemia patients: not a rare but potentially under-recognised condition

Table 3 Differentiation between TDT and NTDT

	TDT more likely	NTDT more likely
Clinical
Presentation (years)	<2	>2
Hb levels (g/dL)	6-7	8-10
Liver/spleen enlargement	Severe	Moderate to severe
Growth retardation/pubertal failure*	+++/++++	Negative to ++
Clinical anaemia affecting daily living	Yes	No
Bone deformity/thalassaemic facie	Yes	Negative to mild
Haematologic
Nucleated RBC (mm³)	Numerous	Negative to few
Reticulocytosis	≥10% of RBC	<10% RBC
Molecular
Type of globin defects	Severe	Mild/silent
Co-inheritance of ameliorating genetic modifiers^†	No	Yes
Co-inheritance of deteriorating genetic modifiers^†	Yes	No

Modified from Thalassaemia International Federation Guideline (2008'second edition).
*Growth retardation; ++, P < 25P, +++, <10P and ++++ = <3P;
^†Ameliorating genetic modifiers represent genetic factors that can reduce globin imbalance such as β-thalassaemia and/or quantitative trait loci that increase †-globin expression in β-thalassaemia intermedia or HbE/β-thalassaemia, β-thalassaemia gene in HbH disease.
^†Deteriorating genetic modifiers include genetic polymorphisms that can further advance disease severity directly and indirectly such as multiple alpha globin gene rearrangements, genetic haemochromatosis, vitamin D receptor, UGT1A1, α-Hb stabilizing protein polymorphism etc.

ISSN: 1750-1172