Single step PCR for the identification of low density lipoprotein receptor (LDL-R) gene mutations

Background and Objective: This study was conducted to determine the common mutation of low density lipoprotein receptor in patients with familial hypercholesterolemia (FH) in our population and identify the different point mutation in the LDL-receptor gene. The main aim of this study was to reduce the cost of PCR without extracting DNA and do the diagnosis at single step.

Methods: This study was carried out in the period of one year, from 2009- 2011. All the patients selected for this study were from Dr. Ziauddin Hospital, National Institute of Cardiovascular Diseases, and Dr. Rubina Ghani’s Pathological & Molecular Laboratories. While collecting the blood sample, the patients were in overnight fasting condition. The clinical and biochemical analysis was performed on hyperlipidemic patients (n=120) to determine the frequency of familial hypercholesterolemia in our population. After lipid profile the patients were selected and direct multiplex PCR (Polymerase chain reaction) was performed from whole blood collected in a single tube using forward and reverse primers of exons 3, 4, 9 and 14 of without extracting DNA.

Results: Genomic DNA was extracted from blood samples as well as direct whole ETDA blood of healthy control group and hypercholesterolemia patients to detect mutations in exons 3, 4, 9, and 14 of the LDLR gene, with modification in the technique by using type-specific primers. These results for exon 4 mutation were confirmed by DNA sequencing.

Conclusion: Screening method based on PCR by using Kappa direct PCR could be a faster and cheaper method with least contamination for screening a large number of FH patients for mutation of LDLR gene.