Test Directory
aHUS Genetic Panel
Justification
The clinical presentation of thrombotic microangiopathy (TMA) has been associated with multiple genetic disease including atypical hemolytic uremic syndrome (aHUS), thrombotic thrombocytopenic purpura (TTP), C3 glomerulopathy (C3G), congenital B12 deficiency and others. These are difficult-to-diagnose, very sick patients with distinct treatment depending on the nature of the TMA. Accurate, rapid diagnosis is critical. Additionally, patients with the C5 p.Arg885 polymorphism may respond poorly to the current approved therapy, eculizumab.
STAT: < 48 hours (M-F)
NGS
Draw Tube: Purple Top
Sample Type: EDTA Whole Blood
Specimen Requirements
Sample Type | Volume Required | Minimum Volume | Stability | |
---|---|---|---|---|
PREFERRED | EDTA Whole Blood | 3mL | 1mL | Room Temp.: 1 month Refrigerated: 1 month |
ALTERNATIVE | Cheek swab | 2 swab | - | Room Temp.: 1 month Refrigerated: 1 month |
REJECTION CRITERIA | Sample contamination; sample compromised |
SPECIAL INSTRUCTIONS | Post bone marrow transplant (post-BMT) patients require a cheek swab sample to test the transplant recipient; post-BMT patients require a venous blood sample to test the bone marrow donor. |
General Information
METHODOLOGY | NGS |
STAT TAT | < 48 hours (M-F) |
STAT TAT Performance | > 90% of results released in 48 hours |
ROUTINE TAT | < 5 days (M-F) |
ALTERNATIVE NAMES | TMA genetic panel; TMA-Complete; complement-mediated TMA panel; C3 glomerulopathy panel; complement-mediated HUS; cm-HUS; aHUS |
DESCRIPTION | The exonic regions of 20 genes are sequenced and analyzed as part of this panel, including ADAMTS13, C2, C3, C3AR1, CD46 (MCP), CFB, CFD, CFH, CFHR1, CFHR2, CFHR3, CFHR4, CFHR5, CFI, DGKE, MASP2, MMACHC, THBD, PLG, WT1 and one SNP in C5 (C5 p.Arg885). In addition to picking up both known and novel single nucleotide variants, this test also detects the large deletions in CFHR3-1 and CFHR1-4. Rare, pathogenic CFH fusions are best detected using our CFH MLPA assay. Sanger sequencing is performed to confirm certain variants. |
LIMITATIONS | This test will not detect variants located outside of the targeted DNA regions. This test is not optimized to detect chimerism or somatic mosaicism. This test will detect small indels but may miss larger deletions or duplications. Balanced structural variants will not be detected unless specifically targeted by a custom PCR assay. |
NORMAL RANGE | Interpretation: Negative |
ASSOCIATED TESTING | - |
REFERENCES | Bu, F et al. Clin Dev Immunol 2012; 2012: 370426 |
SAMPLE REPORT | Upon request |
NEW YORK STATE APPROVED | Yes |
Test Codes
ORDER CODE | P3346 |
CPT CODE | 81404, 81405, 81479x19 |
LOINC CODE | 51779-7 |