OBJECTIVE: To explore the genetic etiology of a Chinese pedigree affected with infantile hepatitis syndrome. METHODS: Genes associated with liver diseases subjected to high-throughput sequencing. Candidate variants were validated by Sanger sequencing of the proband and his parents. The pathogenicity of the variants was analyzed through bioinformatic analysis. RESULTS: High-throughput sequencing revealed that the proband has harbored c.182T>C (p.F61S) and c.293C>T (p.P98L) variants of the MPV17 gene, which were verified by Sanger sequencing to be inherited from his parents. The variant c.182T>C (p.F61S) was unreported previously and predicted to be likely pathogenic by bioinformatic analysis. CONCLUSION The proband was caused by the compound heterozygous variations of MPV17 gene including c.182T>C (p.F61S) and c.293C>T (p.P98L). Discovery of the novel variant has enriched the spectrum of pathogenic variants of the MPV17 gene.
China ; DNA, Mitochondrial/genetics* ; Female ; Genetic Testing ; Humans ; Membrane Proteins/genetics* ; Metabolism, Inborn Errors/genetics* ; Mitochondrial Proteins/genetics* ; Mutation ; Pedigree ; Pregnancy ; Prenatal Diagnosis ; Syndrome

Ageratina adenophora is a noxious plant and it is known to cause acute asthma, diarrhea, depilation, and even death in livestock (Zhu et al., 2007; Wang et al., 2017). A. adenophora grows near roadsides and degraded land worldwide (He et al., 2015b). In the areas where it grows, A. adenophora is an invasive species that inhibits the growth of local plants and causes poisoning in animals that come in contact with it (Nie et al., 2012). In China, these plants can be found in Yunnan, Sichuan, Guizhou, Chongqing, and other southwestern areas (He et al., 2015a) and they have become a dominant species in these local regions. It threatens the native biodiversity and ecosystem in the invaded areas and causes serious economic losses (Wang et al., 2017). It has been reported that A. adenophora can grow in the northeast direction at a speed of 20 km per year in China (Guo et al., 2009). Because of the damage caused by A. adenophora, it ranks among the earliest alien invasive plant species in China (Wang et al., 2017).
Adenosine Triphosphatases/metabolism* ; Ageratina/toxicity* ; Animals ; Biodiversity ; Chemical and Drug Induced Liver Injury/pathology* ; China ; DNA, Mitochondrial/genetics* ; Ecosystem ; Introduced Species ; Liver/drug effects* ; Mice ; Microscopy, Electron, Transmission ; Mitochondria, Liver/pathology* ; Plant Extracts/toxicity*

Mitochondrial diseases are maternally inherited heterogeneous disorders that are primarily caused by mitochondrial DNA (mtDNA) mutations. Depending on the ratio of mutant to wild-type mtDNA, known as heteroplasmy, mitochondrial defects can result in a wide spectrum of clinical manifestations. Mitochondria-targeted endonucleases provide an alternative avenue for treating mitochondrial disorders via targeted destruction of the mutant mtDNA and induction of heteroplasmic shifting. Here, we generated mitochondrial disease patient-specific induced pluripotent stem cells (MiPSCs) that harbored a high proportion of m.3243A>G mtDNA mutations and caused mitochondrial encephalomyopathy and stroke-like episodes (MELAS). We engineered mitochondrial-targeted transcription activator-like effector nucleases (mitoTALENs) and successfully eliminated the m.3243A>G mutation in MiPSCs. Off-target mutagenesis was not detected in the targeted MiPSC clones. Utilizing a dual fluorescence iPSC reporter cell line expressing a 3243G mutant mtDNA sequence in the nuclear genome, mitoTALENs displayed a significantly limited ability to target the nuclear genome compared with nuclear-localized TALENs. Moreover, genetically rescued MiPSCs displayed normal mitochondrial respiration and energy production. Moreover, neuronal progenitor cells differentiated from the rescued MiPSCs also demonstrated normal metabolic profiles. Furthermore, we successfully achieved reduction in the human m.3243A>G mtDNA mutation in porcine oocytes via injection of mitoTALEN mRNA. Our study shows the great potential for using mitoTALENs for specific targeting of mutant mtDNA both in iPSCs and mammalian oocytes, which not only provides a new avenue for studying mitochondrial biology and disease but also suggests a potential therapeutic approach for the treatment of mitochondrial disease, as well as the prevention of germline transmission of mutant mtDNA.
Animals ; DNA, Mitochondrial ; genetics ; Humans ; Induced Pluripotent Stem Cells ; cytology ; metabolism ; MELAS Syndrome ; genetics ; Male ; Mice ; Microsatellite Repeats ; genetics ; Mitochondria ; genetics ; metabolism ; Mutation ; genetics

BACKGROUND: To the best of our knowledge, the association between pediatric AML and mitochondrial aberrations has not been studied. We investigated various mitochondrial aberrations in pediatric AML and evaluated their impact on clinical outcomes. METHODS: Sequencing, mitochondrial DNA (mtDNA) copy number determination, mtDNA 4,977-bp large deletion assessments, and gene scan analyses were performed on the bone marrow mononuclear cells of 55 pediatric AML patients and on the peripheral blood mononuclear cells of 55 normal controls. Changes in the mitochondrial mass, mitochondrial membrane potential, and intracellular reactive oxygen species (ROS) levels were also examined. RESULTS: mtDNA copy numbers were about two-fold higher in pediatric AML cells than in controls (P<0.0001). Furthermore, a close relationship was found between mtDNA copy number tertiles and the risk of pediatric AML. Intracellular ROS levels, mitochondrial mass, and mitochondrial membrane potentials were all elevated in pediatric AML. The frequency of the mtDNA 4,977-bp large deletion was significantly higher (P< 0.01) in pediatric AML cells, and pediatric AML patients harboring high amount of mtDNA 4,977-bp deletions showed shorter overall survival and event-free survival rates, albeit without statistical significance. CONCLUSIONS: The present findings demonstrate an association between mitochondrial genome alterations and the risk of pediatric AML.
Bone Marrow Cells/metabolism ; Case-Control Studies ; Child ; Cohort Studies ; DNA, Mitochondrial/chemistry/genetics/metabolism ; Female ; Flow Cytometry ; Gene Deletion ; Gene Dosage ; *Genome, Mitochondrial ; Humans ; Leukemia, Myeloid, Acute/genetics/mortality/*pathology ; Male ; Membrane Potential, Mitochondrial ; Minisatellite Repeats/genetics ; Odds Ratio ; Reactive Oxygen Species/metabolism ; Sequence Analysis, DNA ; Survival Rate

OBJECTIVETo investigate the relationship between the changes of the copy numbers of mtDNA in peripheral blood mono-nucle- ar cell(PBMC) and the disordered of antioxidant capacity of hepatocellular carcinoma (HCC) patients.

METHODSThe Ficoll Hypaque method was used to isolate the PBMC from blood specimens. The ND1 gene of the mitochondrial was amplified by real-time PCR; meantime β-actin was served as a quantitative standard marker; the difference of mtDNA copy number in PBMC was compared between HCC and healthy control group. The level of reactive oxygen species (ROS) in PBMC was determined by flow cytometry. The change of total antioxidant capacity (T- AOC) of plasma was detected by the biochemistry examination.

RESULTSThe copy numbers of ND1 gene in PBMC of HCC was 73% that of the healthy control group,which suggested a decrease of the copy numbers of mtDNA in HCC. The levels of ROS of PBMC in HCC was (417. 82 ± 110.62) and (301.82 ± 75.54) in control group, which showed that the levels of ROS of PBMC in HCC were significant higher than that in control group (P < 0.01).Plasma T-AOC in HCC was (1.30 ± 0.85), and (3.20 ± 1.62) in control. The T-AOC of plasma of HCC was significantly lower than in control group (P < 0.01).

CONCLUSIONThere was a certain relationship between the decrease of the copy numbers of mtDNA and the disordered antioxidant capacity in hepatocellular carcinoma, which may be associated with the development of hepatocellular carcinoma.

Actins ; Antioxidants ; metabolism ; Carcinoma, Hepatocellular ; blood ; genetics ; Case-Control Studies ; DNA Copy Number Variations ; DNA, Mitochondrial ; genetics ; Humans ; Leukocytes, Mononuclear ; metabolism ; Liver Neoplasms ; blood ; genetics ; Reactive Oxygen Species ; metabolism

BACKGROUND: A newborn screening (NBS) program has been utilized to detect asymptomatic newborns with inherited metabolic diseases (IMDs). There have been some bottlenecks such as false-positives and imprecision in the current NBS tests. To overcome these issues, we developed a multigene panel for IMD testing and investigated the utility of our integrated screening model in a routine NBS environment. We also evaluated the genetic epidemiologic characteristics of IMDs in a Korean population. METHODS: In total, 269 dried blood spots with positive results from current NBS tests were collected from 120,700 consecutive newborns. We screened 97 genes related to NBS in Korea and detected IMDs, using an integrated screening model based on biochemical tests and next-generation sequencing (NGS) called NewbornSeq. Haplotype analysis was conducted to detect founder effects. RESULTS: The overall positive rate of IMDs was 20%. We identified 10 additional newborns with preventable IMDs that would not have been detected prior to the implementation of our NGS-based platform NewbornSeq. The incidence of IMDs was approximately 1 in 2,235 births. Haplotype analysis demonstrated founder effects in p.Y138X in DUOXA2, p.R885Q in DUOX2, p.Y439C in PCCB, p.R285Pfs*2 in SLC25A13, and p.R224Q in GALT. CONCLUSIONS: Through a population-based study in the NBS environment, we highlight the screening and epidemiological implications of NGS. The integrated screening model will effectively contribute to public health by enabling faster and more accurate IMD detection through NBS. This study suggested founder mutations as an explanation for recurrent IMD-causing mutations in the Korean population.
Computational Biology ; DNA/chemistry/isolation & purification/metabolism ; Dried Blood Spot Testing ; Galactokinase ; Genomics ; Haplotypes ; High-Throughput Nucleotide Sequencing ; Humans ; Incidence ; Infant, Newborn ; Membrane Proteins/genetics ; Metabolic Diseases/*diagnosis/epidemiology/genetics ; Metabolism, Inborn Errors/diagnosis/epidemiology/genetics ; Mitochondrial Membrane Transport Proteins/genetics ; Neonatal Screening ; Polymorphism, Genetic ; Republic of Korea/epidemiology ; Sequence Analysis, DNA

Mitochondrial diseases is a group of metabolic disorders caused by abnormal structure and dysfunction of mitochondrial DNA (mtDNA). Abnormalities of mtDNA include point mutations, deletions, and rearrangements and depletion of mtDNA. These may affect the ability of mitochondria to generate energy in cells of various tissues and organs. As many factors are involved in the regulation of mtDNA mutations, most mitochondrial diseases may manifest great genetic heterogeneity and a wide spectrum of clinical manifestations. On the other hand, for the low prevalence of single disease, these disorders may be easily missed or with delayed diagnosis. This review focuses on the pathological mutations and benign variations of mtDNA, and research progress on such disorders.
Biomedical Research ; methods ; trends ; DNA, Mitochondrial ; genetics ; Energy Metabolism ; genetics ; Genetic Heterogeneity ; Humans ; Mitochondria ; genetics ; metabolism ; Mitochondrial Diseases ; diagnosis ; genetics ; Mutation

Mitochondria are important intracellular organelles that produce energy for cellular development, differentiation, and growth. Mitochondrial DNA (mtDNA) presents a 10- to 20-fold higher susceptibility to genetic mutations owing to the lack of introns and histone proteins. The mtDNA repair system is relatively inefficient, rendering it vulnerable to reactive oxygen species (ROS) produced during ATP synthesis within the mitochondria, which can then target the mtDNA. Under conditions of chronic inflammation and excess stress, increased ROS production can overwhelm the antioxidant system, resulting in mtDNA damage. This paper reviews recent literature describing the pathophysiological implications of oxidative stress, mitochondrial dysfunction, and mitochondrial genome aberrations in aging hematopoietic stem cells, bone marrow failure syndromes, hematological malignancies, solid organ cancers, chronic inflammatory diseases, and other diseases caused by exposure to environmental hazards.
DNA, Mitochondrial/*genetics/metabolism ; Hematologic Diseases/genetics/*pathology ; Humans ; *Inflammation ; Mitochondria/genetics ; Mutation ; Neoplasms/genetics/*pathology ; Oxidative Stress ; Reactive Oxygen Species/metabolism

OBJECTIVETo explore the role of mitochondrial DNA 5178 C/A (Mt5178) polymorphism of NADH-dehydrogenase subunit 2 (ND2) gene in type-2 diabetes mellitus (T2DM) among ethnic Han Chinese through a case-control study.

METHODSThe Mt5178C/A polymorphism was determined by sequencing 1103 T2DM patients and 791 healthy controls. Logistic regression analysis was conducted to estimate odds ratios (OR) and 95% confidence intervals (CI). To confirm the results, a meta-analysis was conducted based on published literature on the association of Mt5178 variant with T2DM.

RESULTSNo significant association was found between the Mt5178C/A variant and T2DM either by our study or the meta-analysis which included eight published studies. Nevertheless, it was found that the T2DM patients with 5178C genotype were at a higher risk for nephropathy complication (OR=1.49, 95%CI: 1.005-2.197, P<0.05) and at significantly lower risk for hypertension complication (OR=0.744, 95%CI: 0.556-0.996, P<0.05) compared with those carrying a 5178A genotype.

CONCLUSIONNo association was found between the Mt5178C/A polymorphism of mitochondrial ND2 gene with the increased risk of T2DM. However, the polymorphism may affect the development of nephropathy and hypertension complications among T2DM patients.

Adult ; Aged ; Blood Glucose ; metabolism ; Cholesterol ; blood ; Cholesterol, HDL ; blood ; DNA, Mitochondrial ; chemistry ; genetics ; Diabetes Complications ; blood ; genetics ; Diabetes Mellitus, Type 2 ; blood ; complications ; genetics ; Diabetic Nephropathies ; blood ; genetics ; Fasting ; blood ; Female ; Humans ; Hypertension ; blood ; complications ; genetics ; Male ; Meta-Analysis as Topic ; Middle Aged ; Odds Ratio ; Polymorphism, Single Nucleotide ; Sequence Analysis, DNA ; Triglycerides ; blood

Many researchers have reported that oxidative damage to mitochondrial DNA (mtDNA) is increased in several age-related disorders. Damage to mitochondrial constituents and mtDNA can generate additional mitochondrial dysfunction that may result in greater reactive oxygen species production, triggering a circular chain of events. However, the mechanisms underlying this vicious cycle have yet to be fully investigated. In this review, we summarize the relationship of oxidative stress-induced mitochondrial dysfunction with mtDNA mutation in neurodegenerative disorders.
Animals ; DNA, Mitochondrial/*genetics ; Humans ; Mitochondria/drug effects/genetics/metabolism ; Molecular Targeted Therapy ; *Mutation ; Neurodegenerative Diseases/drug therapy/*genetics/metabolism ; Reactive Oxygen Species/metabolism