Many late-stage chronic Lyme disease clinical findings are neuropsychiatric. A total clinical assessment is critical in diagnosis, especially since controversy surrounds the reliability of laboratory testing. The clinical findings of one hundred Lyme disease patients with chronic neuropsychiatric symptoms were entered into a database. The prevalence of each clinical finding pre-infection and post-infection was compared and calculated within the 95% confidence interval. Patients had minimal symptoms pre-infection, but a high post-infection prevalence of a broad spectrum of acquired multisystem symptoms. These findings included impairments of attention span, memory, processing, executive functioning, emotional functioning, behavior, psychiatric syndromes, vegetative functioning, neurological, musculoskeletal, cardiovascular, upper respiratory, dental, pulmonary, gastrointestinal, genitourinary, and other symptoms. The most prevalent symptoms included sustained attention impairments, brain fog, unfocused concentration, joint symptoms, distraction by frustration, depression, working memory impairments, decreased school/job performance, recent memory impairments, difficulty prioritizing multiple tasks, fatigue, non-restorative sleep, multitasking difficulties, sudden mood swings, hypersomnia, mental apathy, decreased social functioning, insomnia, tingling, word finding difficulties, name retrieval, headaches, sound hypersensitivity, paresis, anhedonia, depersonalization, cold intolerance, body temperature fluctuations, light sensitivity and dysfluent speech. The average patient had five symptoms pre-infection and 82 post-infection. Pattern recognition is critical in making a diagnosis. This study was used to develop three clinical assessment forms.

Mitochondrial mutational signature is very conserved and low deviations between species have been associated with longevity. By reconstructing species-specific mtDNA mutational spectrum for ray-finned fishes (Actinopterygii), we observed that temperature is a strong additional factor shaping the mtDNA mutational spectrum in ectotherms. The analysis of mammalian endotherms, with a special focus on species with temporarily or permanently low metabolic rates (hibernators, daily torpors, naked mole rat, etc.), confirmed the temperature effect, suggesting that two main factors shape between-species variation in mitochondrial mutational spectra: longevity and temperature.

The A-to-G point mutation at position 3243 in the human mitochondrial genome (m.3243A > G) is the most common pathogenic mtDNA variant responsible for disease in humans. It is widely accepted that m.3243A > G levels decrease in blood with age, and an age correction representing ~ 2% annual decline is often applied to account for this change in mutation level. Here we report that recent data indicate that the dynamics of m.3243A > G are more complex and depend on the mutation level in blood in a bi-phasic way. Consequently, the traditional 2% correction, which is adequate ‘on average’, creates opposite predictive biases at high and low mutation levels. Unbiased age correction is needed to circumvent these drawbacks of the standard model. We propose to eliminate both biases by using an approach where age correction depends on mutation level in a biphasic way to account for the dynamics of m.3243A > G in blood. The utility of this approach was further tested in estimating germline selection of m.3243A > G. The biphasic approach permitted us to uncover patterns consistent with the possibility of positive selection for m.3243A > G. Germline selection of m.3243A > G shows an ‘arching’ profile by which selection is positive at intermediate mutant fractions and declines at high and low mutant fractions. We conclude that use of this biphasic approach will greatly improve the accuracy of modelling changes in mtDNA mutation frequencies in the germline and in somatic cells during aging.

The A-to-G point mutation at position 3243 in the human mitochondrial genome (m.3243A>G) is the most common pathogenic mtDNA variant responsible for disease in humans. It is widely accepted that m.3243A>G levels decrease in blood with age, and correction representing ~2% annual decline is often applied to account for this change in mutation level. Here we report that recent data indicate the dynamics of m.3243A>G are far more complex and depend on the blood mutation level in a bi-phasic way. As a consequence, the traditional 2% correction, which is adequate on 'average', creates opposite predictive biases at high and low mutation levels. Thus, overall accuracy of traditional correction depends on the proportion of individuals with high and low mutant levels in the dataset. Unbiased age correction is needed to circumvent these drawbacks of the standard model. We propose to abolish both biases by using an approach where correction depends on mutation level in biphasic way, to account for the biphasic dynamics of m.3243A>G in blood. The significance of removing bias was further tested using germline selection as a model, in which we detected mutation patterns consistent with the possibility of positive selection for m.3243A>G. We conclude that use of bi-phasic approach will greatly improve the predictive accuracy of modeling data for changes in mtDNA mutations in the germline and in somatic cells during aging.

The resilience of the mitochondrial genome (mtDNA) to a high mutational pressure depends, in part, on negative purifying selection against detrimental mutations in the germline. Floros et al. reported a sharp increase in the synonymity of mtDNA mutations between early and late- stage primordial germ cells (PGCs), concomitant with a shift from glycolytic to oxidative metabolism, as evidenced by comparing data from pooled samples of early vs late PGCs. They thus asserted that this metabolic shift exposed deleterious mtDNA mutations to negative selection. We re- analyzed Floros data to resolve a perceived inconsistency of the pattern of synonymity change and discovered a significant contamination of pooled PGC mutations with nuclear sequence derived from mtDNA (NUMT). We determined that contamination was caused by co- amplification of the NUMT sequence by cross-specific PCR primers. Importantly, when we removed NUMT-derived sequence variants from pooled PGC data, the evidence of purifying selection in late PGCs was abolished. We then turned to mutations of single PGCs, also from the same group, for which no synonymity analysis was reported. We found no evidence of NUMT contamination of single PGCs mutations. This is consistent with the use of a different set of PCR primers which are unable to amplify NUMT since they were positioned outside the NUMT sequence. Importantly, we further demonstrated that single PGC mutations show a significant decrease of synonymity with increased mutant fraction. This observation is incompatible with predominantly purifying selection of mtDNA mutations in PGCs at these mutant fractions and suggests that selection may be predominantly positive.