Eight Cases of Hb Winnipeg [HBA2: c.226G > T (or HBA1)]: A Detailed Study

Hb Winnipeg [alpha 75(EF4)Asp -> Tyr (alpha 2); HBA2: c.226G>T (or HBA1)] is a stable alpha-globin chain variant described in a few articles. The majority of reported cases in older articles were clustered in Canada. It can occur on both alpha 1- and alpha 2-globin genes and in different populations. In this study, eight cases of Hb Winnipeg were characterized by DNA sequencing during a wide-spectrum study of suspected alpha-globin gene variants collected in the United Kingdom. All cases detected peaked in the S window between 4.4 and 4.54 min. on high performance liquid chromatography (HPLC). The isoelectric focusing (IEF) averaged at 6.21 below Hb A. All the mutations were detected on the alpha 1-globin gene except in one case. The ethnic origin of the majority of the patients was Canadian. Only one case was associated with the common polymorphism HBA2: c.-24C>G (or HBA1) [Cap +14 (C>G)] on both alpha-globin genes without any apparent effect on the variant expression. All cases were detected in a heterozygous state. Hb Winnipeg expression was consistently lower than the theoretical value for alpha chain variants, ranging between 11.8 and 15.8% of total hemoglobin (Hb). This study gave more details about Hb Winnipeg that may help in presumptive diagnosis, especially in routine laboratories.