This Week in Clinical Chemistry

Baylor College of Medicine investigators present a one-step mitochondrial genome analysis approach in Clinical Chemistry. By combining long-range PCR and massively parallel sequencing, the Baylor researchers were able to detect point mutations as well as large deletions in mtDNA. They analyzed 45 samples and determined that their approach had 100 percent diagnostic sensitivity and specificity as compared to Sanger sequencing results. "This one-step comprehensive approach makes qualitative and quantitative calls for every nucleotide position of the entire mitochondrial genome. It can simultaneously detect large mtDNA deletions as well as small indels, identifying both the breakpoints and the degree of heteroplasmy," the researchers write. "We believe this novel approach will greatly facilitate the diagnosis of mitochondrial diseases in a timely and cost-effective fashion."

In a review in Clinical Chemistry, researchers at the University of Oxford say that meta-analyses of biomarker studies "have the power to provide robust evidence to support our understanding of the role of novel biomarkers for disease," though they also have a number of limitations. The authors draw on two examples of biomarkers for cardiovascular disease risk — homocysteine and triglycerides — and how meta-analyses of those have helped generate hypotheses but also misleading findings. However, they note that additional information from randomized controlled trials and genetic studies may help refine the roles of biomarkers in predicting cardiovascular disease.