A Rare Case of Compound Heterozygous Sickle Cell Beta Thalassaemia with High HbF and Normal HbA2 Levels Detected on HPLC

Abstract

Compound heterozygous Sickle Haemoglobin (HbS) beta (β) thalassaemia arises from the mutations associated with sickle cell and β thalassaemia and significantly affects populations in low income countries like India. Elevated levels of Haemoglobin A2 (HbA2) represent the primary indicator for identifying carriers of β thalassaemia. However, it’s worth noting that sometimes, High Performance Liquid Chromatography (HPLC) encounters challenges in confirming a final diagnosis when levels of HbA2 and HbS fall outside the diagnostic range. A nine-year-old male and his sister 11-year-old female patient presented with high-grade fever and jaundice since two weeks. Following admission, Complete Blood Count (CBC) and HPLC of both children were done. Hb of male and female child revealed 1.8 g/dL and 1.5 g/dL, respectively. HPLC of male child revealed Haemoglobin F (HbF) 27.4%, HbS 56.3%, HbA2 3.8% and of female child revealed HbF 39.2%, HbS 43.5%, HbA2 3%. HPLC reports of both children were suggestive of differential of compound heterozygous HbS β thalassaemia and HbS homozygous. Later, HPLC of their parents was also done. HPLC of father was suggestive of thalassaemia trait and of mother suggestive of sickle cell trait, following which final diagnosis of both children was given as compound heterozygous HbS β thalassaemia. Diagnosing these compound heterozygous haemoglobinopathies can be challenging. As their is resemblance in clinicopathological features of sickle cell anaemia and β thalassaemia disorders, it is important to carefully differentiate between them although prognosis is better than thalassaemia major or sickle cell anaemia.

Keywords

• compound heterozygous sickle cell β thalassaemia
• foetal haemoglobin
• haemoglobin a2
• haemolytic anaemia
• high performance liquid chromatography
• sickling