“…While significant advances have been reported in the detection of the GPI-AP-deficient cells, as well as in the pathophysiology of the disease, the natural history and the identification of survival prognostic factors in PNH have been rarely described. 8,10,13,15,19 From earlier descriptions, the clinical spectrum of PNH has resulted in two described forms of presentation: one form, predominantly haemolytic without overt marrow failure, referred to as classic PNH 1-6 (and reviewed in Young et al 4 and Parker et al 14 ), and the other one with marrow failure, often described as the AA-PNH syndrome 29 (and reviewed in Young et al 4 and Parker et al 14 ). This dichotomy was used as a working classification but did not really encompass the clinical spectrum of the disease.…”