Related Experiment Video
Updated: Sep 19, 2025
Single Droplet Digital Polymerase Chain Reaction for Comprehensive and Simultaneous Detection of Mutations in Hotspot Regions
Published on: September 25, 2018
Recombinase polymerase amplification for single nucleotide polymorphism-specific detection of βC variant in sickle
Mehnaz Urbee Jahangir1, Megan M Chang2, Alexis Wilkinson1
1Department of Bioengineering, Rice University, Houston, TX, USA.
Insights
A new Recombinase Polymerase Amplification (RPA) assay enables rapid and low-cost detection of the sickle cell disease (SCD) βC allele. This innovation improves genetic testing accessibility for hemoglobinopathies in resource-limited settings.
Area of Science:
- Molecular Biology
- Genetic Diagnostics
- Biotechnology
Background:
- Sickle cell disease (SCD) is an inherited blood disorder with limited early diagnosis in low- and middle-income countries due to costly DNA tests.
- Existing Recombinase Polymerase Amplification (RPA) methods can amplify multiple β-globin alleles, including the clinically distinct βC allele, complicating SCD diagnosis.
- Accurate and accessible genetic testing is crucial for managing SCD, especially for the βC variant.
Purpose of the Study:
- To develop a novel, allele-specific RPA fluorescent assay for the selective detection of the βC allele.
- To optimize primer design using Amplification Refractory Mutation System (ARMS) and Locked Nucleic Acid (LNA) modifications for enhanced specificity.
- To establish a rapid, low-cost diagnostic tool for SCD, particularly the βC variant, for use in resource-limited settings.
Main Methods:
- Development of allele-specific RPA primers incorporating ARMS and LNA modifications.
- Screening of twelve forward primer variants to identify optimal sequences for βC allele specificity.
- Evaluation of primer performance, including limit of detection and specificity, using fluorescent detection.
Main Results:
- A novel primer design combining a single mismatch near the 3' end with a terminal LNA modification achieved specific amplification of the βC allele.
- The optimized assay demonstrated a limit of detection of 100 copies per reaction for the βC allele.
- Key design principles were identified for creating robust, SNP-specific RPA assays, including strategic placement of mismatches and LNA modifications.
Conclusions:
- The study successfully established an isothermal RPA assay for the specific detection of the βC allele, crucial for SCD diagnosis.
- The findings provide systemic design strategies for developing future SNP-specific RPA assays.
- This advancement holds significant potential for expanding affordable and rapid genetic testing for hemoglobinopathies in underserved regions.
Abstract:
Sickle cell disease (SCD) comprises a group of inherited blood disorders caused by point mutations in the β-globin gene. SCD is characterized by at least one βS globin allele and a second pathologic globin variant that results in predominant formation of hemoglobin S (HbS). Early diagnosis in low-and middle-income countries is limited by the high cost and complexity of DNA-based tests. Recombinase Polymerase Amplification (RPA) is an isothermal nucleic acid amplification technique that facilitates rapid and low-cost detection of genetic mutations. While RPA primers have been developed to detect wild-type βA and βS alleles, they can also amplify the βC allele, the next most common hemoglobin variant causing SCD which requires distinct clinical management. We developed a novel allele-specific RPA fluorescent assay for selective detection of the βC allele using primers incorporating Amplification Refractory Mutation System (ARMS) and Locked Nucleic Acid (LNA) modifications. Twelve forward primers with different modifications were screened to achieve βC-specific amplification. The best-performing primer combined a single mismatch near the 3' end with an LNA at the terminal base, enabling specific detection of βC with a limit of detection of 100 copies per reaction. Key design insights include avoiding mismatches immediately before the LNA for consistent target amplification and positioning the LNA closer to the 3' end to achieve less sensitive amplification. This study establishes an isothermal assay for SCD diagnosis and offers systemic design strategies for SNP-specific RPA assays. These findings have important implications for expanding affordable, rapid genetic testing for hemoglobinopathies in low-resource settings.
More Related Videos
11:59Detection of Residual Donor Erythroid Progenitor Cells after Hematopoietic Stem Cell Transplantation for Patients with Hemoglobinopathies
Published on: September 6, 2017
07:17Author Spotlight: Advancing the Detection of Low-Frequency Mutations in Cancer Tissues
Published on: August 23, 2024