Visual single nucleotide polymorphism (SNP) detection for ALDH2 genotyping based on multiplex ligation probe amplification (MLPA) and lateral flow assay

Current techniques for single nucleotide polymorphism (SNP) detection require laborious experimental procedures, expensive and sophisticated instruments, as well as complex data analysis, which make it difficult to meet the demand for routine clinical laboratories or point of care testing (POCT). In this study, the authors propose a reliable and cost-effective method by integrating multiplex ligation probe amplification (MLPA) and gold nanoparticles (AuNPs)-based lateral flow assay (LFA) for visual detection of the ALDH2 gene rs671(G > A) polymorphism. The genotyping result can be easily observed with the naked eye within 5-10 min after loading the MLPA products on the LFA device. This system demonstrates high sensitivity with LOD down to 1 ng, meeting the requirement in clinical diagnostic. Furthermore, this method has been implemented in clinical practices to identify the genotypes of the ALDH2 gene. The results obtained from the MLPA-LFA, Sanger sequencing, and high-resolution melting (HRM) curve analysis demonstrate a perfect agreement rate of 100%. Compared to conventional genotyping assays, this system exhibits the following advantages, including visual interpretation of results, minimal requirements for sophisticated instruments and highly skilled technicians, time efficiency, as well as low cost with a price approximately at 5 dollars. We believe that the MLPA-LFA system is a robust and versatile method with the potential to detect other SNPs related to disease susceptibility and risk, as well as drug metabolism and therapeutic effects.