Sensitive quantification of m.3243A>G mutational proportion in non-retinal tissues and its relationship with visual symptoms.

The m.3243A>G mutation in the mitochondrial genome commonly causes retinal degeneration in patients with maternally inherited diabetes and deafness and mitochondrial encephalopathy, lactic acidosis and stroke-like episodes. Like other mitochondrial mutations, m.3243A>G is inherited from the mother with a variable proportion of wild type and mutant mitochondrial genomes in different cells. The mechanism by which the m.3243A>G variant in each tissue relates to the manifestation of disease phenotype is not fully understood. Using a digital PCR assay, we found that the % m.3243G in skin derived dermal fibroblasts was positively correlated with that of blood from the same individual. The % m.3243G detected in fibroblast cultures remained constant over multiple passages and was negatively correlated with mtDNA copy number. Although the % m.3243G present in blood was not correlated with severity of vision loss, as quantified by Goldmann visual field, a significant negative correlation between % m.3243G and the age of onset of visual symptoms was detected. Altogether, these results indicate that precise measurement of % m.3243G in clinically accessible tissues such as skin and blood may yield information relevant to the management of retinal m.3243A>G-associated disease.

Mandatory certification of forensic science practitioners in the United States: A supportive perspective.

The article presented is supportive of mandatory certification of forensic scientists and believes that such a mandate can help establish a threshold for competency in the profession, provide a universal standard for ethical professional conduct, and enhance the credibility of forensic science in users of the profession and the general societal public. After examining the history of professional certification in the United States across a spectrum of professions including forensic science, results of surveys sent to forensic science practitioners to gauge their views on mandatory certification is discussed. Seventy-three surveys were received with most surveyors being in support of mandatory certification related to their discipline. Reasons why many practitioners have chosen not to engage in voluntary certification were also provided on the surveys and discussed. Finally, the article discusses possible ways of implementing mandatory certification and concludes that the mechanisms to achieve this goal may already be in place.