Emerging therapeutic drug monitoring technologies: considerations and opportunities in precision medicine.

In recent years, the development of sensor and wearable technologies have led to their increased adoption in clinical and health monitoring settings. One area that is in early, but promising, stages of development is the use of biosensors for therapeutic drug monitoring (TDM). Traditionally, TDM could only be performed in certified laboratories and was used in specific scenarios to optimize drug dosage based on measurement of plasma/blood drug concentrations. Although TDM has been typically pursued in settings involving medications that are challenging to manage, the basic approach is useful for characterizing drug activity. TDM is based on the idea that there is likely a clear relationship between plasma/blood drug concentration (or concentration in other matrices) and clinical efficacy. However, these relationships may vary across individuals and may be affected by genetic factors, comorbidities, lifestyle, and diet. TDM technologies will be valuable for enabling precision medicine strategies to determine the clinical efficacy of drugs in individuals, as well as optimizing personalized dosing, especially since therapeutic windows may vary inter-individually. In this mini-review, we discuss emerging TDM technologies and their applications, and factors that influence TDM including drug interactions, polypharmacy, and supplement use. We also discuss how using TDM within single subject (N-of-1) and aggregated N-of-1 clinical trial designs provides opportunities to better capture drug response and activity at the individual level. Individualized TDM solutions have the potential to help optimize treatment selection and dosing regimens so that the right drug and right dose may be matched to the right person and in the right context.

Does Modulation of an Epigenetic Clock Define a Geroprotector?

There is growing interest in the development of interventions (e.g., drugs, diets, dietary supplements, behavioral therapies, etc.) that can enhance health during the aging process, prevent or delay multiple age-related diseases, and ultimately extend lifespan. However, proving that such 'geroprotectors' do what they are hypothesized to do in relevant clinical trials is not trivial. We briefly discuss some of the more salient issues surrounding the design and interpretation of clinical trials of geroprotectors, including, importantly, how one defines a geroprotector. We also discuss whether emerging surrogate endpoints, such as epigenetic clocks, should be treated as primary or secondary endpoints in such trials. Simply put, geroprotectors should provide overt health and disease prevention benefits but the time-dependent relationships between epigenetic clocks and health-related phenomena are complex and in need of further scrutiny. Therefore, studies that enable understanding of the relationships between epigenetic clocks and disease processes while simultaneously testing the efficacy of a candidate geroprotector are crucial to move the field forward.

Psychometric Properties of a New Stress-Related Personality Scale: The Virtual Inventory of Behavior and Emotions (VIBE).

BACKGROUND: Personality traits are important factors with regard to the tendency to experience and response to stress. This study introduces and tests a new stress-related personality scale called the Virtual Inventory of Behavior and Emotions (VIBE). METHODS: Two samples totaling 5512 individuals (with 66% between the ages of 18 and 34) completed the VIBE along with other measures of personality, stress, mood, and well-being. RESULTS: Exploratory factor analyses revealed a four-factor structure for the instrument with dimensions labeled: 1) stressed; 2) energetic; 3) social; and 4) disciplined. Confirmatory factor analytic procedures on the final 23-item version showed good psychometric properties and data fit while machine learning analyses demonstrated the VIBE's ability to distinguish between groups with similar patterns of response. Strong convergent validity was suggested through robust correlations between the dimensions of the VIBE and other established rating scales. CONCLUSION: Overall, the data suggest that the VIBE is a promising tool to help advance understanding of the relations between stress, personality, and related constructs.

Correction: Association Between Improvement in Baseline Mood and Long-Term Use of a Mindfulness and Meditation App: Observational Study.

[This corrects the article DOI: 10.2196/12617.].

Characterizing Emotional State Transitions During Prolonged Use of a Mindfulness and Meditation App: Observational Study.

BACKGROUND: The increasing demand for mental health care, a lack of mental health care providers, and unequal access to mental health care services have created a need for innovative approaches to mental health care. Digital device apps, including digital therapeutics, that provide recommendations and feedback for dealing with stress, depression, and other mental health issues can be used to adjust mood and ultimately show promise to help meet this demand. In addition, the recommendations delivered through such apps can also be tailored to an individual's needs (ie, personalized) and thereby potentially provide greater benefits than traditional "one-size-fits-all" recommendations. OBJECTIVE: This study aims to characterize individual transitions from one emotional state to another during the prolonged use of a digital app designed to provide a user with guided meditations based on their initial, potentially negative, emotional state. Understanding the factors that mediate such transitions can lead to improved recommendations for specific mindfulness and meditation interventions or activities (MMAs) provided in mental health apps. METHODS: We analyzed data collected during the use of the Stop, Breathe & Think (SBT) mindfulness app. The SBT app prompts users to input their emotional state before and immediately after engaging with MMAs recommended by the app. Data were collected from more than 650,000 SBT users engaging in nearly 5 million MMAs. We limited the scope of our analysis to users with 10 or more MMA sessions that included at least 6 basal emotional state evaluations. Using clustering techniques, we grouped emotions recorded by individual users and then applied longitudinal mixed effect models to assess the associations between individual recommended MMAs and transitions from one group of emotions to another. RESULTS: We found that basal emotional states have a strong influence on transitions from one emotional state to another after MMA engagement. We also found that different MMAs impact these transitions, and many were effective in eliciting a healthy transition but only under certain conditions. In addition, we observed gender and age effects on these transitions. CONCLUSIONS: We found that the initial emotional state of an SBT app user determines the type of SBT MMAs that will have a favorable effect on their transition from one emotional state to another. Our results have implications for the design and use of guided mental health recommendations for digital device apps.

Association Between Improvement in Baseline Mood and Long-Term Use of a Mindfulness and Meditation App: Observational Study.

BACKGROUND: The use of smartphone apps to monitor and deliver health care guidance and interventions has received considerable attention recently, particularly with regard to behavioral disorders, stress relief, negative emotional state, and poor mood in general. Unfortunately, there is little research investigating the long-term and repeated effects of apps meant to impact mood and emotional state. OBJECTIVE: We aimed to investigate the effects of both immediate point-of-intervention and long-term use (ie, at least 10 engagements) of a guided meditation and mindfulness smartphone app on users' emotional states. Data were collected from users of a mobile phone app developed by the company Stop, Breathe & Think (SBT) for achieving emotional wellness. To explore the long-term effects, we assessed changes in the users' basal emotional state before they completed an activity (eg, a guided meditation). We also assessed the immediate effects of the app on users' emotional states from preactivity to postactivity. METHODS: The SBT app collects information on the emotional state of the user before and after engagement in one or several mediation and mindfulness activities. These activities are recommended and provided by the app based on user input. We considered data on over 120,000 users of the app who collectively engaged in over 5.5 million sessions with the app during an approximate 2-year period. We focused our analysis on users who had at least 10 engagements with the app over an average of 6 months. We explored the changes in the emotional well-being of individuals with different emotional states at the time of their initial engagement with the app using mixed-effects models. In the process, we compared 2 different methods of classifying emotional states: (1) an expert-defined a priori mood classification and (2) an empirically driven cluster-based classification. RESULTS: We found that among long-term users of the app, there was an association between the length of use and a positive change in basal emotional state (4% positive mood increase on a 2-point scale every 10 sessions). We also found that individuals who were anxious or depressed tended to have a favorable long-term emotional transition (eg, from a sad emotional state to a happier emotional state) after using the app for an extended period (the odds ratio for achieving a positive emotional state was 3.2 and 6.2 for anxious and depressed individuals, respectively, compared with users with fewer sessions). CONCLUSIONS: Our analyses provide evidence for an association between both immediate and long-term use of an app providing guided meditations and improvements in the emotional state.

Parsing heterogeneity in attention-deficit hyperactivity disorder using EEG-based subgroups.

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is a heterogeneous condition for which multiple efforts to characterize brain state differences are underway. The objective of this study was to identify distinct subgroups of resting electroencephalography (EEG) profiles among children with and without ADHD and subsequently provide extensive clinical characterization of the subgroups. METHODS: Latent class analysis was used with resting state EEG recorded from a large sample of 781 children with and without ADHD (N = 620 ADHD, N = 161 Control), aged 6-18 years old. Behavioral and cognitive characteristics of the latent classes were derived from semistructured diagnostic interviews, parent completed behavior rating scales, and cognitive test performance. RESULTS: A five-class solution was the best fit for the data, of which four classes had a defining spectral power elevation. The distribution of ADHD and control subjects was similar across classes suggesting there is no one resting state EEG profile for children with or without ADHD. Specific latent classes demonstrated distinct behavioral and cognitive profiles. Those with elevated slow-wave activity (i.e. delta and theta band) had higher levels of externalizing behaviors and cognitive deficits. Latent subgroups with elevated alpha and beta power had higher levels of internalizing behaviors, emotion dysregulation, and intact cognitive functioning. CONCLUSIONS: There is population-level heterogeneity in resting state EEG subgroups, which are associated with distinct behavioral and cognitive profiles. EEG measures may be more useful biomarkers of ADHD outcome or treatment response rather than diagnosis.

Novel splice-affecting variants in CYP27A1 gene in two Chilean patients with Cerebrotendinous Xanthomatosis.

Cerebrotendinous Xanthomatosis (CTX), a rare lipid storage disorder, is caused by recessive loss-of-function mutations of the 27-sterol hydroxylase (CYP27A1), producing an alteration of the synthesis of bile acids, with an accumulation of cholestanol. Clinical characteristics include juvenile cataracts, diarrhea, tendon xanthomas, cognitive impairment and other neurological manifestations. Early diagnosis is critical, because treatment with chenodeoxycholic acid may prevent neurological damage. We studied the CYP27A1 gene in two Chilean CTX patients by sequencing its nine exons, exon-intron boundaries, and cDNA from peripheral blood mononuclear cells. Patient 1 is a compound heterozygote for the novel substitution c.256-1G > T that causes exon 2 skipping, leading to a premature stop codon in exon 3, and for the previously-known pathogenic mutation c.1183C > T (p.Arg395Cys). Patient 2 is homozygous for the novel mutation c.1185-1G > A that causes exon 7 skipping and the generation of a premature stop codon in exon 8, leading to the loss of the crucial adrenoxin binding domain of CYP27A1.

A parietal biomarker for ADHD liability: as predicted by the distributed effects perspective model of ADHD.

BACKGROUND: We previously hypothesized that poor task-directed sensory information processing should be indexed by increased weighting of right hemisphere (RH) biased attention and visuo-perceptual brain functions during task operations and have demonstrated this phenotype in ADHD across multiple studies, using multiple methodologies. However, in our recent distributed effects model of ADHD, we surmised that this phenotype is not ADHD specific, but rather more broadly reflective of any circumstance that disrupts the induction and maintenance of an emergent task-directed neural architecture. Under this view, increased weighting of RH-biased attention and visuo-perceptual brain functions is expected to generally index neurocognitive sets that are not optimized for task-directed thought and action, and when durable expressed, liability for ADHD. METHOD: The current study tested this view by examining whether previously identified rightward parietal EEG asymmetry in ADHD was associated with common ADHD characteristics and comorbidities [i.e., ADHD risk factors (RFs)]. RESULTS: Barring one exception (non-right handedness), we found that it was. Rightward parietal asymmetry (RPA) was associated with carrying the DRD4-7R risk allele, being male, having mood disorder, and having anxiety disorder. However, differences in the specific expression of RPA were observed, which are discussed in relation to possible unique mechanisms underlying ADHD liability in different ADHD RFs. CONCLUSION: Rightward parietal asymmetry appears to be a durable feature of ADHD liability, as predicted by the Distributed Effects Perspective Model of ADHD. Moreover, variability in the expression of this phenotype may shed light on different sources of ADHD liability.

Community-Based Mindfulness Program for Disease Prevention and Health Promotion: Targeting Stress Reduction.

PURPOSE: Poorly managed stress leads to detrimental physical and psychological consequences that have implications for individual and community health. Evidence indicates that U.S. adults predominantly use unhealthy strategies for stress management. This study examines the impact of a community-based mindfulness training program on stress reduction. DESIGN: This study used a one-group pretest-posttest design. SETTING: The study took place at the UCLA Mindful Awareness Research Center in urban Los Angeles. SUBJECTS: A sample of N = 127 community residents (84% Caucasian, 74% female) were included in the study. INTERVENTION: Participants received mindfulness training through the Mindful Awareness Practices (MAPs) for Daily Living I. MEASURES: Mindfulness, self-compassion, and perceived stress were measured at baseline and postintervention. ANALYSIS: Paired-sample t-tests were used to test for changes in outcome measures from baseline to postintervention. Hierarchical regression analysis was fit to examine whether change in self-reported mindfulness and self-compassion predicted postintervention perceived stress scores. RESULTS: There were statistically significant improvements in self-reported mindfulness (t = -10.67, p < .001, d = .90), self-compassion (t = -8.50, p < .001, d = .62), and perceived stress (t = 9.28, p < .001, d = -.78) at postintervention. Change in self-compassion predicted postintervention perceived stress (ß = -.44, t = -5.06, p < .001), but change in mindfulness did not predict postintervention perceived stress (ß = -.04, t = -.41, p = .68). CONCLUSION: These results indicate that a community-based mindfulness training program can lead to reduced levels of psychological stress. Mindfulness training programs such as MAPs may offer a promising approach for general public health promotion through improving stress management in the urban community.

[Cerebrotendinous xanthomatosis: physiopathology, clinical manifestations and genetics]. / Xantomatosis cerebrotendinosa: aspectos fisiopatológicos, clínicos y genéticos.

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disease, caused by genetic deficiency of the 27-hydroxylase enzyme (encoded by CYP27A1). It plays a key role in cholesterol metabolism, especially in bile acid synthesis and in the 25-hydroxylation of vitamin D3 in the liver. Its deficiency causes reduced bile acid synthesis and tissue accumulation of cholestanol. Clinical manifestations are related to the presence of cholestanol deposits and include tendon xanthomas, premature cataracts, chronic diarrhea, progressive neurologic impairment and less frequently coronary heart disease, early onset osteoporosis and abnormalities in the optic disk and retina. An early diagnosis and treatment with quenodeoxycholic acid may prevent further complications, mainly neurological manifestations. This review summarizes cholesterol metabolism related to bile acid synthesis, physiopathology, biochemistry and treatment of cerebrotendinous xanthomatosis.

[Association between genetic polymorphisms of interleukin 6 (IL6), IL6R and IL18 with metabolic syndrome in obese Chilean children]. / Polimorfismos genéticos de interleuquina 6 (IL6), IL6R e IL18: asociación con componentes del síndrome metabólico en niños chilenos con obesidad.

BACKGROUND: Metabolic Syndrome (MS) is highly prevalent among obese children and adolescents and is considered a predictor for the development of type 2 diabetes mellitus and cardiovascular disease. Obesity is associated with an increase in circulating levels of interleukins 6 (IL6) and 18 (IL18), which in turn would depend on polymorphisms of IL6, IL6R and IL18 genes. AIM: To evaluate the association between genetic polymorphisms of IL6 (rs1800795, rs1800796 and rs1800797), IL6R (rs2228145) and IL18 (rs360719, rs187238 and rs204355) and MS and/or its components in a sample of Chilean obese children. PATIENTS AND METHODS: These polymorphisms were genotyped in 259 obese children aged 10 ± 2 years with a body mass index of 26.1 ± 4.1 kg/m². Sixty eight had metabolic syndrome (26.3%). The association of their alleles, genotypes and haplotypes with the MS and its components was assessed. RESULTS: IL6, IL6R and IL18 variants showed no association with SM nor with any of the phenotypes that compose it. However, IL18 haplotypes (rs360719-rs187238-rs204355) TCT and CGT were associated with triglycerides ≤ 110 mg/dL and HDL < 40 mg/dL, respectively. CONCLUSIONS: IL6 and IL6R variants are not associated with MS or with any of its phenotypes. Although an association between IL18 haplotypes and certain MS component has been detected herein, it is necessary to replicate our findings in independent studies due to the low frequency of these allele combinations detected in our sample.

Xantomatosis cerebrotendinosa: aspectos fisiopatológicos, clínicos y genéticos / Cerebrotendinous xanthomatosis: physiopathology, clinical manifestations and genetics

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disease, caused by genetic deficiency of the 27-hydroxylase enzyme (encoded by CYP27A1). It plays a key role in cholesterol metabolism, especially in bile acid synthesis and in the 25-hydroxylation of vitamin D3 in the liver. Its deficiency causes reduced bile acid synthesis and tissue accumulation of cholestanol. Clinical manifestations are related to the presence of cholestanol deposits and include tendon xanthomas, premature cataracts, chronic diarrhea, progressive neurologic impairment and less frequently coronary heart disease, early onset osteoporosis and abnormalities in the optic disk and retina. An early diagnosis and treatment with quenodeoxycholic acid may prevent further complications, mainly neurological manifestations. This review summarizes cholesterol metabolism related to bile acid synthesis, physiopathology, biochemistry and treatment of cerebrotendinous xanthomatosis.

Polimorfismos genéticos de interleuquina 6 (IL6), IL6R e IL18: asociación con componentes del síndrome metabólico en niños chilenos con obesidad / Association between genetic polymorphisms of interleukin 6 (IL6), IL6R and IL18 with metabolic syndrome in obese Chilean children

Background: Metabolic Syndrome (MS) is highly prevalent among obese children and adolescents and is considered a predictor for the development of type 2 diabetes mellitus and cardiovascular disease. Obesity is associated with an increase in circulating levels of interleukins 6 (IL6) and 18 (IL18), which in turn would depend on polymorphisms of IL6, IL6R and IL18 genes. Aim: To evaluate the association between genetic polymorphisms of IL6 (rs1800795, rs1800796 and rs1800797), IL6R (rs2228145) and IL18 (rs360719, rs187238 and rs204355) and MS and/or its components in a sample of Chilean obese children. Patients and Methods: These polymorphisms were genotyped in 259 obese children aged 10 ± 2 years with a body mass index of 26.1 ± 4.1 kg/m². Sixty eight had metabolic syndrome (26.3%). The association of their alleles, genotypes and haplotypes with the MS and its components was assessed. Results: IL6, IL6R and IL18 variants showed no association with SM nor with any of the phenotypes that compose it. However, IL18 haplotypes (rs360719-rs187238-rs204355) TCT and CGT were associated with triglycerides ≤ 110 mg/dL and HDL < 40 mg/dL, respectively. Conclusions: IL6 and IL6R variants are not associated with MS or with any of its phenotypes. Although an association between IL18 haplotypes and certain MS component has been detected herein, it is necessary to replicate our findings in independent studies due to the low frequency of these allele combinations detected in our sample.

Divergent metabolic phenotype between two sisters with congenital generalized lipodystrophy due to double AGPAT2 homozygous mutations. a clinical, genetic and in silico study.

Congenital generalized lipodystrophy (CGL) is a rare autosomal recessive disorder characterized by extreme reduction of white adipose tissue (WAT) mass. CGL type 1 is the most frequent form and is caused by mutations in AGPAT2. Genetic and clinical studies were performed in two affected sisters of a Chilean family. These patients have notoriously dissimilar metabolic abnormalities that correlate with differential levels of circulating leptin and soluble leptin receptor fraction. Sequencing of AGPAT2 exons and exon-intron boundaries revealed two homozygous mutations in both sisters. Missense mutation c.299G>A changes a conserved serine in the acyltransferase NHX4D motif of AGPAT2 (p.Ser100Asn). Intronic c.493-1G>C mutation destroy a conserved splicing site that likely leads to exon 4 skipping and deletion of whole AGPAT2 substrate binding domain. In silico protein modeling provided insights of the mechanisms of lack of catalytic activity owing to both mutations.

Randomised controlled pilot trial of mindfulness training for stress reduction during pregnancy.

This randomised controlled pilot trial tested a six-week mindfulness-based intervention in a sample of pregnant women experiencing high levels of perceived stress and pregnancy anxiety. Forty-seven women enrolled between 10 and 25 weeks gestation were randomly assigned to either a series of weekly Mindful Awareness Practices classes (n = 24) with home practice or to a reading control condition (n = 23). Hierarchical linear models of between-group differences in change over time demonstrated that participants in the mindfulness intervention experienced larger decreases from pre-to post-intervention in pregnancy-specific anxiety and pregnancy-related anxiety (PRA) than participants in the reading control condition. However, these effects were not sustained through follow-up at six weeks post-intervention. Participants in both groups experienced increased mindfulness, as well as decreased perceived stress and state anxiety over the course of the intervention and follow-up periods. This study is one of the first randomised controlled pilot trials of a mindfulness meditation intervention during pregnancy and provides some evidence that mindfulness training during pregnancy may effectively reduce PRA and worry. We discuss some of the dilemmas in pursuing this translational strategy and offer suggestions for researchers interested in conducting mind-body interventions during pregnancy.

Association of RNASEL and 8q24 variants with the presence and aggressiveness of hereditary and sporadic prostate cancer in a Hispanic population.

To study the association between the polymorphisms Arg462Gln and Asp541Glu from the RNASEL gene (1q25), and the polymorphisms rs620861, rs1447295, rs6983267, rs7837328 from the chromosome 8q24 with the risk of presenting prostate cancer (PCa) and its clinical characteristics in a Hispanic (Chilean) population. The study was performed on 21 control patients and 83 patients diagnosed with PCa. Polymorphisms were analysed from blood samples through real-time PCR by using TaqMan probes, and the genetic analysis was performed with the SNPStats program. Also, a comparison was performed between clinical characteristics of PCa and the presence of the different polymorphism genotypes by using the Minitab software. There was a significant association between the genotype G/G from the polymorphism rs6983267 with an overall increased risk of PCa, in patients both with or without family history of PCa (OR = 4.47, 95% CI = 1.05-18.94, P = 0.034 and OR = 3.57, 95% CI = 0.96-13.35, P = 0.037, respectively). Regarding clinical parameters, patients carrying the genotype C/C from the polymorphism Asp541Glu had significantly higher prostate-specific antigen (PSA) levels than patients carrying the other genotypes (P = 0.034). Moreover, patients with the genotype G/G of rs6983267 had higher PSA levels (P = 0.024). The polymorphism rs6983267 from region 3 of the chromosome 8q24 appears to be a prominent risk factor for PCa and a biomarker for cancer aggressiveness in the group of patients who presented higher levels of PSA at the time of diagnosis.

Melanocortin-4 receptor polymorphism rs17782313: association with obesity and eating in the absence of hunger in Chilean children.

OBJECTIVE: The aim of this study was to assess the association between melanocortin-4 receptor (MC4R) rs17782313 alleles with obesity and eating behavior scores in Chilean children. METHODS: A case-control study was conducted with 139 normal-weight and 238 obese children (ages 6-12 y). MC4R rs17782313 genotypes were determined by quantitative-polymerase chain reaction allelic-discrimination assays. Eating behavior scores were evaluated in a subset of participants using the Chilean version of the Child Eating Behavior Questionnaire (CEBQ). Additionally, five normal-weight C-allele carriers of rs17782313 were matched by sex, age, and body mass index (BMI) to five TT homozygous children to carry out the Eating in the Absence of Hunger (EAH) test. RESULTS: The frequency of the C-allele of MC4R rs17782313 was higher in the obese group than in the control group, without achieving statistical significance (odds ratio, 1.4; 95% confidence interval, 0.8-2.4; P = 0.16). CEBQ scores of "enjoyment of food" were higher (P = 0.04) and "satiety responsiveness" were lower (P = 0.02) in children with CC genotype than in those with TT genotype matched by sex, age, and BMI. In the EAH test, all five non-obese carriers of the C-allele (three CC and two CT) showed increased sweet snack consumption compared with five matched (by sex-age-BMI) non-carriers after a preload meal, without achieving statistical significance (P = 0.06). CONCLUSION: MC4R polymorphism rs17782313 may contribute to childhood obesity, affecting enjoyment of food, satiety responsiveness, and possibly eating in the absence of hunger.

[Mitochondrial DNA heteroplasmy of the m.3243A>G mutation in maternally inherited diabetes and deafness]. / Heteroplasmia de la mutación del ADN mitocondrial m.3243A>G en la diabetes y sordera de herencia materna.

Maternally Inherited Diabetes and Deafness (MIDD) is caused by mutations in mitochondrial DNA (mtDNA), mainly m.3243A>G. Severity, onset and clinical phenotype of MIDD patients are partially determined by the proportion of mutant mitochondrial DNA copies in each cell and tissue (heteroplasmy). The identification of MIDD allows a corred treatment with insulin avoiding drugs that may interfere with mitochondrial electrón chain transpon. We estimated the degree of heteroplasmy of the mutation m.3243A>G from blood, saliva, hair root and a muscle biopsy using quantitative PCR (qPCR) in a femóle adult patient. For this purpose, PCR producís were inserted in a vector creating plasmids with 3243A or G. Mutant and wild-type vectors were mixed in different proportions to créate a calibration curve used to interpólate heteroplasmy percentages with qPCR threshold cycles. The proportions of m.3243A>G heteroplasmy were 62% (muscle), 14% (saliva), 6% (blood leukocytes) and 3% in hair root. Quantitative analysis of heteroplasmy showed marked variations in different tissues (highest in muscle and lowest in blood). Given the relatively high heteroplasmy found in saliva, this type of biológical sample may represent an adequate non-invasive way for assessing the presence of m.3243A>G mutations in epidemiologic studies.

Heteroplasmia de la mutación del ADN mitocondrial m.3243A>G en la diabetes y sordera de herencia materna / Mitochondrial DNA heteroplasmy of the m.3243A>G mutation in maternally inherited diabetes and deafness

Maternally Inherited Diabetes and Deafness (MIDD) is caused by mutations in mitochondrial DNA (mtDNA), mainly m.3243A>G. Severity, onset and clinical phenotype of MIDD patients are partially determined by the proportion ofmutant mitochondrial DNA copies in each cell and tissue (heteroplasmy). The identification ofMIDD allows a corred treatment with insulin avoiding drugs that may interfere with mitochondrial electrón chain transpon. We estimated the degree of heteroplasmy ofthe mutation m.3243A>G from blood, saliva, hair root and a muscle biopsy using quantitative PCR (qPCR) in a femóle adult patient. For this purpose, PCR producís were inserted in a vector creatingplasmids with 3243A or G. Mutant and wild-type vectors were mixed in different proportions to créate a calibration curve used to interpólate heteroplasmy percentages with qPCR threshold cycles. The proportions of m.3243A>G heteroplasmy were 62% (muscle), 14% (saliva), 6% (blood leukocytes) and 3% in hair root. Quantitative analysis of heteroplasmy showed marked variations in different tissues (highest in muscle and lowest in blood). Given the relatively high heteroplasmy found in saliva, this type of biológical sample may represent an adequate non-invasive way for assessing the presence of m.3243A>G mutations in epidemiologic studies.