Preferred Minimum: 8 mL whole blood Absolute Minimum: 4 mL whole blood

Complement Factor I Atypical Hemolytic-Uremic Syndrome The clinical manifestations of hemolytic-uremic syndrome (HUS) include hemolytic anemia, thrombocytopenia and acute renal failure. Most cases are associated with epidemics of diarrhea caused by verocytotoxin-producing bacteria. Atypical hemolytic uremic syndrome (aHUS) is a rarer disease. It is not associated with Stx-HUS infection and neither does it present with watery, bloody diarrhea (Warwicker et all, 1997). It can be either sporadic or familial and has an extremely unfavorable prognosis, with about 50% of persons progressing to ESRD and 25% dying during the acute illness; transplantation in many survivors is unsuccessful (Schieppati et al., 1992; Taylor et al., 2004). Genetics studies have shown that approximately 50% of cases of aHUS are caused by mutations in MCP, CFH and IF(Caprioli et al., 2006). Identifying the genetic cause of aHUS is extremely important as it can help to direct clinical treatment decisions. Complement Factor I (CFI) Factor I is a proteolytic enzyme that destroys the hemolytic and immune-adherence activities of cell-bound, activated C3. The CFI gene contains 13 exons and encodes the 583 amino acid protein, Complement Factor I. There have been at least 23 reported cases of Factor I-deficient patients. Sensitivity is greater than 99%.