Eleven Cases of Hb J-Paris-I [HBA2: c.38C>A (or HBA1)]: A Stable α Chain Variant Elutes in the P3 Window on High-Performance Liquid Chromatography

Abstract

Hb J-Paris-I [HBA2: c.38C>A (or HBA1)] is a stable fast-moving hemoglobin (Hb) that elutes in the P3 window on high performance liquid chromatography (HPLC). The mutation can happen on either the α1- or α2-globin gene. Codon 12 changes from GCC to GAC to replace the alanine amino acid with aspartic acid. This change is external with no clinical significance. The elution in the P3 wave on HPLC can interfere with the glycated Hb assay by HPLC. In this study, data of 11 cases of Hb J-Paris-I were thoroughly presented. The majority of the cases were of Indian ethnicity. The mean value of Hb J-Paris-I on HPLC was 26.7 ± 2.0%. The retention time (RT) was 1.75 ± 0.03 min. The isoelectric focusing (IEF) mean value was −5.6 (range −6.1 to −4.9). Hb A₂ was consistently reduced to 1.8 ± 0.3%. A fraction of 0.8% corresponding to the Hb A₂-J-Paris-I (α₂^J-Paris-Iδ₂) is likely to be concealed within the A₀ peak of Hb A on HPLC. Interestingly, two cases were associated with two different polymorphisms [HBA2: c.-24C>G or Cap +14 (C>G) and HBA2: c.*136A>G polymorphism] without apparent effect on the variant expression.

Keywords:

• α Variant
• hemoglobin (Hb)
• Hb J-Paris-I
• Cap +14 (C>G)
• HBA2: c.*136A>G polymorphism

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article. The views expressed in this publication are those of the authors and not necessarily those of the Department of Health.

Additional information

Funding

This study was supported by the European Commission grant for the project “eInfrastructure for Thalassaemia Research Network,” Co-ordination Action, ITHANET [RI-2004–026539], and also by the Oxford Partnership Comprehensive Biomedical Research Centre with funding from the Department of Health’s National Institute of Health Biomedical Research Centre’s funding scheme.