Digital droplet PCR versus quantitative PCR for lipoprotein (a) kringle IV type 2 repeat polymorphism genetic...

Area of Science:

• Cardiovascular Genetics
• Molecular Diagnostics
• Biotechnology

Background:

• Lipoprotein(a) [Lp(a)] level variability is a key factor in atherothrombotic risk, primarily influenced by the LPA gene.
• Kringle IV type 2 (KIV2) copy number variation (CNV) within the LPA gene is the main genetic determinant of Lp(a) levels.
• Accurate detection of KIV2 repeat polymorphism is challenging due to the complex structural characteristics of Lp(a) variants.

Purpose of the Study:

• To compare the performance of quantitative real-time PCR (qPCR) and digital droplet PCR (ddPCR) for evaluating KIV2 repeat polymorphism.
• To assess the reliability and accuracy of ddPCR versus qPCR in quantifying KIV2 CNV.
• To investigate the correlation between KIV2 CNV, Lp(a) levels, and cardiovascular risk.

Main Methods:

• Analysis of 100 subjects with assessed cardiovascular risk and Lp(a) plasma levels.
• Quantitative real-time PCR (qPCR) for KIV2 CNV quantification.
• Digital droplet PCR (ddPCR) for KIV2 CNV quantification.
• Statistical correlation analysis between KIV2 CNV values obtained by both methods and Lp(a) levels.

Main Results:

• ddPCR demonstrated superior stability and reduced intra/inter-assay variation compared to qPCR.
• A significant inverse correlation between Lp(a) levels and KIV2 CNV was observed for both methods, with stronger significance for ddPCR.
• Subjects with Lp(a) levels above 500 mg/L showed a significantly lower number of KIV2 repeats, more pronounced with ddPCR analysis.

Conclusions:

• ddPCR exhibits better performance and higher reliability for the evaluation of KIV2 repeat polymorphism than qPCR.
• The findings support ddPCR as a more accurate method for assessing KIV2 CNV, crucial for understanding Lp(a)-associated cardiovascular risk.
• Improved KIV2 CNV quantification using ddPCR can enhance the assessment of atherothrombotic risk stratification.