text: Conventional SNP typing methods are typically time-consuming and expensive, requiring several probe based assays to be multiplexed together or the use of DNA microarrays. HRM is more cost-effective and reduces the need to design multiple pairs of primers and the need to purchase expensive probes. The HRM method has been successfully used to detect a single G to A substitution in the gene Vssc (Voltage Sensitive Sodium Channel) which confers resistance to the acaricide permethrin in Scabies mite. This mutation results in a coding change in the protein (G1535D). The analysis of scabies mites collected from suspected permethrin susceptible and tolerant populations by HRM showed distinct melting profiles.  The amplicons from the sensitive mites were observed to have a higher melting temperature relative to the tolerant mites, as expected from the higher thermostability of the GC base pair
  In a field more relevant to clinical diagnostics, HRM has been shown to be suitable in principle for the detection of mutations in the breast cancer susceptibility genes BRCA1 and BRCA2. More than 400 mutations have been identified in these genes.<br />The sequencing of genes is the gold standard for identifying mutations. Sequencing is time-consuming and labour-intensive and is often preceded by techniques used to identify heteroduplex DNA, which then further amplify these issues.  HRM  offers a faster and more convenient closed-tube method of assessing the presence of mutations and gives a result which can be further investigated if it is of interest.  In a study carried out by Scott et al. in 2006, 3 cell lines harbouring different BRCA mutations were used to assess the HRM methodology. It was found that the melting profiles of the resulting PCR products could be used to distinguish the presence or absence of a mutation in the amplicon. Similarly in 2007 Krypuy et al. showed that the careful design of  HRM assays (with regards to primer placement) could be successfully employed to detect mutations in the TP53 gene, which encodes the tumour suppressor protein p53 in clinical samples of breast and ovarian cancer.  Both these studies highlighted the fact that changes in the melting profile can be in the form of a shift in the melting temperature or an obvious difference in the shape of the melt curve.  Both of these parameters are a function of the amplicon sequence.
  The consensus is that HRM is a cost efficient method that can be employed as an initial screen for  samples suspected of harbouring polymorphisms or mutations.  This would reduce the number of samples which need to be investigated further using more conventional methods.