Test Directory
CFH Region Deletion/Duplication Analysis by MLPA
Justification
Due to the homologous nature of these tandem genes, this complement-regulatory region is more susceptible to deletions and duplications. For example, rare deletions in this region that result in a fusion of the CFH gene to CFHR1 can cause atypical hemolytic uremic syndrome (aHUS). Other more common deletions of either CFHR3-1 or CFHR1-4 can be inherited such that many people are homozygous null for CFHR1; these people are more likely than others to develop anti-CFH antibodies, which can cause aHUS.
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 | MLPA |
| STAT TAT | < 48 hours (M-F) |
| STAT TAT Performance | > 90% of results released in 48 hours |
| ROUTINE TAT | < 5 days (M-F) |
| ALTERNATIVE NAMES | CFH fusion, CFH/CFHR copy number variation (CNV) analysis, CFH, CFHR1, CFHR2, CFHR3, CFHR4, CFHR5 deletion/duplication analysis, complement-mediated HUS, cm-HUS, TMA |
| DESCRIPTION | This test looks for deletions or duplications within the CFH, CFHR1, CFHR2, CFHR3, CFHR4 and CFHR5 genes by multiplex ligation-dependent probe amplification (MLPA), a method with much higher resolution than next-generation sequencing or microarrays. |
| LIMITATIONS | This test detects deletions and duplications but not balanced structural variants (i.e., inversions, insertions or translocations). This test requires two consecutive probes indicating a deletion or duplication to make a CNV call. |
| NORMAL RANGE | Interpretation: Negative |
| ASSOCIATED TESTING | - |
| REFERENCES | Venables JP, Strain L, Routledge D, et al. Atypical haemolytic uraemic syndrome associated with a hybrid complement gene. PLoS Med. 2006 Oct;3(10):e431. Zipfel PF, Edey M, Heinen S, et al. Deletion of complement factor H-related genes CFHR1 and CFHR3 is associated with atypical hemolytic uremic syndrome. PLoS Genet. 2007 Mar 16;3(3):e41. Valoti E, Alberti M, Tortajada A, et al. A novel atypical hemolytic uremic syndrome-associated hybrid CFHR1/CFH gene encoding a fusion protein that antagonizes factor H-dependent complement regulation. J Am Soc Nephrol. 2015 Jan;26(1):209-19. |
| SAMPLE REPORT | Upon request |
| NEW YORK STATE APPROVED | No |
Test Codes
| ORDER CODE | P3410 |
| CPT CODE | 81479 |
| LOINC CODE | 51779-7 |