Abstract

High-resolution melting analysis (HRMA) was compared with denaturing high-performance liquid chromatography (dHPLC) for mutation scanning of common mutations in the cystic fibrosis transmembrane conductance regulator gene. We amplified (polymerase chain reaction under conditions optimized for melting analysis or dHPLC) 26 previously genotyped samples with mutations in exons 3, 4, 7, 9, 10, 11, 13, 17b, and 21, including 20 different genotypes. Heterozygous mutations were detected by a change in shape of the melting curve or dHPLC tracing. All 20 samples with heterozygous mutations studied by both techniques were identified correctly by melting (100% sensitivity), and 19 were identified by dHPLC (95% sensitivity). The specificity of both methods also was good, although the dHPLC traces of exon 7 consistently revealed 2 peaks for wild-type samples, risking false-positive interpretation. Homozygous mutations could not be detected using curve shape by either method. However, when the absolute temperatures of HRMA were considered, G542X but not F508del homozygotes could be distinguished from wild type. HRMA easily detected heterozygotes in all single nucleotide polymorphism (SNP) classes (including A/T SNPs) and 1-or 2-base-pair deletions. HRMA had better sensitivity and specificity than dHPLC with the added advantage that some homozygous sequence alterations could be identified. HRMA has great potential for rapid, closed-tube mutation scanning.

Author notes

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Dr Wittwer holds equity interest in Idaho Technology.
Supported by the Institute for Clinical and Experimental Pathology, ARUP Laboratories.