Porphyrins profile by high performance liquid chromatography/electrospray ionization tandem mass spectrometry for the diagnosis of porphyria

Abstract

Porphyrias are a group of inherited or acquired disorders of certain enzymes in the heme bio-synthetic pathway. Most porphyria symptoms are nonspecific and occur intermittently; resulting frequently in missed diagnosis since the disease itself is a rare one. The aim of the study is to establish a new reliable and accurate laboratory method for separation, identification and quantitation of urinary porphyrins by liquid chromatography tandem mass spectrometry (LC/MS/MS) and thereby the diagnosis of different porphyria types for the first time in Egypt. Screening by plasma fluorescence and quantitative determination of urinary porphyrins by high performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC/ESI/MS/MS) of 50 clinically suspected patients revealed one case of variegate porphyria and five cases of porphyria cutanea tarda. Plasma fluorescence scanning is a simple procedure that can be used as screening test to detect porphyria patients that require quantitation of urinary porphyrins as a second step. Quantitative determination of urinary porphyrins using HPLC/ESI/MS/MS and ion mapping techniques are applicable for the differential diagnosis of porphyria types, since each type has a characteristic porphyrins excretion profile. Quantitative determination of urinary porphyrins by HPLC/ESI/MS/MS used in this study is a modification for the method Stoev et al. while ion mapping technique is a new technique invented by the research team at the Biochemical Genetics Department.