Specimen:

Whole Blood

Collection Medium:

Minimum:

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

Analytic Time:

3 months

Reference Range:

None detected

Interpretive Data:

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%.

Comments:

Please print, complete and submit the Kidney Testing Requisition 
from the Molecular Otolaryngology & Renal Research Laboratory, to 
Specimen Control/Mailouts with the specimen and the Epic Requisition.

Methodology:

Oligonucleotide primers have been designed to amplify each exon of CFI.  
Because CFI contains many non-disease causing polymorphisms, it is 
sequenced directly using overlapping primer sets.

CPT Code:

83891, 83894, 83898 (x12), 83904 (x12), 83912