Detection of common sequence variations of familial hypercholesterolemia in Taiwan using DNA mass spectrometry

Familial hypercholesterolemia (FH) is a heterogeneous autosomal dominant disease. The genetic heterogeneity of FH requires low-cost, high-throughput, and rapid mutation detection technology to efficiently integrate genetic screening into clinical practice.The aims of the study were to customize the MassARRAY assay to (1) establish an FH mutation assay panel, comprising known point mutations located on FH-causing genes and (2) test the feasibility of the assay for screening FH patients residing in Taiwan who fit the clinical criteria of FH diagnosis.We designed a custom Agena iPLEX assay to detect 68 point mutations on FH-causing genes. First, the assay performance was verified by analyzing 180 previously sequenced subjects (120 with point mutations and 60 healthy controls), with the results being compared with those of Sanger DNA sequencing. Second, a blind study was carried out on 185 FH probands (44 definite FH and 141 probable/possible FH).In the first part of this study, only 1 discrepancy was found between the Agena iPLEX and Sanger sequencing genotyping results. In the blind study, a total of 62 probands with mutations were identified by both techniques. Five mutations were detected by Sanger sequencing assay only. The detection sensitivity and specificity rates of Agena iPLEX were 92.5% and 100%, respectively, in the blind study. The hands-on time for the Agena iPLEX assay was around 1 day.The custom-designed Agena iPLEX assay has high specificity and sensitivity for FH genetic screening. Considering its low cost, rapidity, and flexibility, the assay has great potential to be incorporated into FH screening in Taiwan.