Protein characterization by LC-MS/MS may be required for the DNA identification of a fusion hemoglobin: the example of Hb P-Nilotic

DNA analysis is currently the easiest way to identify a hemoglobin variant in most cases. Nevertheless, in case of complex gene rearrangements, mass spectrometry studies may be required to orientate the DNA diagnosis. The present report shows the use of mass spectrometry techniques prior to DNA analysis for the identification of the rare P-Nilotic fusion hemoglobin. Complete protein analysis is performed by liquid chromatography–tandem mass spectrometry on the abnormal globin chain isolated by reversed-phase liquid chromatography.