Some patients have genetic risk haplotypes such as CFH-H3 (which identifies the CFHtgtgt risk haplotype) or MCPaaggt and may not have clinically apparent HUS until a condition (such as malignancy, drugs, transplantation, systemic diseases, and infection) triggers an acute TMA episode [8, 9, 10]. The gene discussed is CFH; the disease is hemolytic-uremic syndrome.