Haemoglobin H (Hb H) disease is a form of alpha (α)-thalassaemia where three of the four α-globin gene alleles are deleted. Hb H is usually classified as deletional and non-deletional types; however, the interaction of these two types is also encountered. Clinically, the patients can have a phenotype of thalassaemia intermedia requiring occasional blood transfusion to mild anaemia. Deletional form of Hb H (--/-α) due to double heterozygosity of deletions causing α0-thalassaemia (both α-globin HBA1 and HBA2 gene deleted on the allele) and α+-thalassaemia (single α-globin gene deletion on the other allele) are commonly encountered.1 Non-deletional Hb H variants are Hb Constant Spring, Hb Quong Sze, Hb Sallanches, Hb Seal Rock, Hb Sun Prairie, Poly A; AATAAA→AATA-- of the HBA2 gene, etc.2 Congenital dyserythropoietic anaemia (CDA) is characterised by ineffective erythropoiesis and dyserythropoiesis in the bone marrow (BM), and CDA type II is the most common form. Clinical presentation of patients with CDA type II is highly heterogeneous, ranging from symptomless to transfusion-dependent anaemia. The BM has evident erythroid hyperplasia with the classical presence of binucleate erythroblasts.3 The phenotypic presentation of Hb H disease/α-thalassaemia and CDA type II is similar and often presents with anaemia, pallor, jaundice, splenomegaly, etc. We here report an interesting case of Hb H disease masquerading as CDA type II based on the findings of BM morphology.

A male child in his middle childhood from East India presented to our centre having progressive pallor since 2020. On …