Few publications focus on the mysterious, genetically acquired disease paroxysmal nocturnal hemoglobinuria (PNH) and the related "intractable" disorders aplastic anemia and myelodysplastic syndromes. Now, however, the latest understanding of the clinical and molecular genetic aspects of PNH is summarized here in the proceedings of the International Symposium held in Tokyo in 2001. Major topics reviewed include the molecular mechanisms of the PIG-A gene mutation; complement activation and inhibitors; experimental animal models; pathogenesis; the history of PNH research; the natural history...