Multiplex ARMS analysis to detect 13 common mutations in familial hypercholesterolaemia

Area of Science:

• Genetics and Molecular Biology
• Clinical Diagnostics
• Cardiovascular Medicine

Background:

• Familial hypercholesterolaemia (FH) diagnosis is crucial for identifying at-risk relatives and enabling early intervention.
• Comprehensive genetic screening for FH-causing genes (LDLR, APOB, PCSK9) is often time-consuming and expensive.
• Accurate and efficient DNA analysis is needed for reliable FH diagnosis, particularly in challenging clinical cases.

Purpose of the Study:

• To evaluate the diagnostic utility of a novel multiplex amplification refractory mutation system (ARMS) assay for common FH-causing mutations.
• To assess the sensitivity and specificity of the ARMS assay compared to traditional gene sequencing methods.
• To determine the effectiveness of the ARMS assay as an initial DNA diagnostic test in a UK patient cohort.

Main Methods:

• A multiplex ARMS assay targeting 11 LDLR mutations, one APOB mutation (p.R3527Q), and one PCSK9 mutation (p.D374Y) was developed.
• The assay was tested on DNA samples from 400 patients attending 10 UK lipid clinics.
• Results were compared against a complete screen of the LDLR gene using single-stranded conformation polymorphism/denaturing high-performance liquid chromatography (SSCP/DHPLC).

Main Results:

• The multiplex ARMS kit detected mutations in 54 (14%) of the 400 patients.
• A full LDLR gene screen identified 59 mutations (11 novel) in an additional 87 patients, yielding an overall detection rate of 35%.
• The ARMS kit correctly identified 38% of all mutations found by the full screen, with no false positives or negatives; detection rates were higher in patients with a definite FH clinical diagnosis (49% overall, 52% of full-screen mutations).

Conclusions:

• The multiplex ARMS assay demonstrates good specificity and sensitivity for detecting common FH-causing mutations.
• The assay provides rapid results (within one week) and is a valuable initial DNA diagnostic tool for FH in the UK.
• This approach offers a more efficient and cost-effective alternative to full gene sequencing for initial FH mutation screening.