Quantification of Ggamma- and Agamma-globins by electrospray ionisation mass spectrometry.

Elucidation of the molecular basis for persistent fetal haemoglobin (Hb F) production in adult life has important implications for the pathophysiology and treatment of human beta haemoglobinopathies. Electrospray ionisation mass spectrometry (ESMS) was applied to analyse the pattern of gamma-globin expression in patients with hereditary persistence of fetal haemoglobin (HPFH) and sickle cell anaemia (SCA). Ggamma and Agamma-globin chains were identified by their measured molecular masses and distinguished by mass difference (14 Da) following deconvolution of ESMS spectra using maximum entropy based software. Prediction of HPFH type by ESMS was confirmed by molecular analysis. Direct determination of Ggamma:Agamma globin chain ratio from whole blood by the novel application of ESMS provides a rapid and sensitive approach to characterisation of gamma-globins and facilitates correlation of gamma-globin level and polymorphism of cis-active elements at the beta-globin locus.