Using ddPCR to Identify Large Deletions of Complement Factor H-Related Genes in Atypical Hemolytic Uremic Syndrome
Yu-Wei Cheng1,2, Zhen Wang3, Zheng Jin Tu1
1Department of Laboratory Medicine, Cleveland Clinic, Cleveland, OH, United States.
The Journal of Applied Laboratory Medicine
|May 22, 2026
Summary
Droplet digital PCR (ddPCR) accurately detects large deletions in complement factor H-related (CFHR) genes, offering a cost-effective alternative to MLPA for diagnosing atypical hemolytic uremic syndrome (aHUS). This method shows high concordance and reproducibility.
Area of Science:
- Genetics
- Molecular Biology
- Complement System
Background:
- Atypical hemolytic uremic syndrome (aHUS) is a rare complement-mediated disorder.
- Homozygous deletions in CFHR1, CFHR3, or CFHR4 genes are associated with aHUS.
- Multiplex ligation-dependent probe amplification (MLPA) is typically used for copy number variation (CNV) detection in CFH and CFHR regions.
Purpose of the Study:
- To develop and evaluate a cost-effective droplet digital PCR (ddPCR) method for detecting CNVs in CFHR genes.
- To compare the ddPCR method with MLPA for identifying large deletions in CFHR1, CFHR3, and CFHR4.
Main Methods:
- Developed ddPCR assay with primers designed to avoid single nucleotide polymorphisms for enhanced hybridization.
- Analyzed 41 DNA samples using both ddPCR and MLPA.
- Utilized MRC Holland's Probemix P236 CFH Region for MLPA analysis.
Main Results:
- Identified multiple heterozygous deletions in CFHR1, CFHR3, and CFHR4 genes.
- Observed homozygous deletions of CFHR1 and CFHR3 in two cases each.
- Achieved 100% concordance between ddPCR and MLPA results, with consistent reproducibility.
Conclusions:
- ddPCR is a robust and reliable method for identifying large deletions in CFHR gene regions.
- Further studies are required to assess ddPCR's capability in distinguishing full versus partial deletions.
- The clinical diagnostic value of ddPCR for aHUS requires further establishment.
