Hb Woodville, a rare alpha-globin variant, caused by codon 6 mutation of the alpha1 gene

Since 1995, the national programme for the prevention and control of severe thalassaemia has been implemented in Thailand. This programme is composed of the population screening in pregnant women and couples by osmotic fragility, HbE screening and the confirmation test using haemoglobin analyses by electrophoresis or chromatography. Thereafter, several hitherto unidentified haemoglobins (Hbs) with structural defects are increasingly described and these variants are now easily studied using DNA technology. In this study, the authors describe the haematology and molecular analyses in a 28-yr-old healthy female who was identified as having an exceptionally 'high HbA2' from haemoglobin analysis. Subsequent analyses demonstrated that observed atypical 'HbA2' was, in fact, a rare innocuous alpha-globin variant, called Hb Woodville [alpha 2 6(A4); Asp --> Tyr]. For the first time, this abnormal Hb species is characterised at the molecular level.