A deficiency of MCP has been associated with atypical human uraemic syndrome (aHUS) which is characterized by thrombotic microangiopathies [57], while a deficiency of DAF/CD59 is associated with paroxysmal nocturnal haemoglobinuria (PNH), which also is associated with thrombosis [58]. The gene discussed is CD55; the disease is thrombotic microangiopathy.