Alternative Methods For Detecting Chain Truncations

Many genotyping methods exist which can detect chain truncating mutations as well as other types of mutations. DNA sequencing is considered the gold standard for genotyping as it can detect any mutation that can be amplified by PCR including those that have never been previously described. However, it is expensive and time consuming to carry out complete gene sequencing even with high-throughput automated capillary sequencers. Furthermore, this method is not able to detect a mutant sequence that represents less than 25% of the sample because of the presence of the wild-type signal at every position.[17] Hybridization-based approaches for detecting mutations such as TaqMan® (Applied Biosystems), Invader (Third Wave Technology), and high-density chip arrays (Affymetrix) are high-throughput methods that are only capable of detecting previously identified mutations and will miss de novo mutations.[18] In one study,[19] five different mutation detection methods to detect truncation mutations in BRCA1 were compared. These included four DNA-based methods: two-dimensional gene scanning (TDGS), denaturing high-performance liquid chromatog-raphy (DHPLC), enzymatic mutation detection (EMD), SSCP, and PTT. Analysis of 21 samples showed that PTT correctly identified all 15 deleterious mutations. Not surprisingly, the DNA-based techniques did not detect a deletion of exon 22, and five truncating mutations were missed by SSCP. In another study,[20] researchers compared the effectiveness of PTT and SSCP for detecting BRCA 1 mutations and concluded that PTT is a superior screening test as the specificity of PTT was 100% and sensitivity was 82.6%, whereas for SSCP, the specificity was 99% but the sensitivity was only 60.9%.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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