OBJECTIVE: To explore the genetic basis for a Chinese pedigree with suspected mitochondrial functional defects through combined next-generation sequencing (NGS), copy number variation sequencing (CNV-seq), and mitochondrial DNA (mtDNA) sequencing. METHODS: Clinical data of the proband and his family members were collected. The patient and his parents were subjected to family-trio whole-exome sequencing (WES), CNV-seq and mtDNA variant detection. Candidate variant was verified by Sanger sequencing. RESULTS: Trio-WES revealed that the proband has carried compound heterozygous variants of the NDUFS1 gene, including a paternally derived c.64C>T (p.R22X) nonsense variant and a maternally derived c.845A>G (p.N282S) missense variant. Both variants may cause loss of protein function. No variant that may cause the phenotype was identified by CNV-seq and mtDNA variant analysis. CONCLUSION Children with suspected mitochondrial disorders may have no specific syndromes or laboratory findings. A comprehensive strategy including mtDNA testing may facilitate the diagnosis and early clinical interventions.
Child ; China ; DNA Copy Number Variations ; Electron Transport ; Humans ; Mutation ; NADH Dehydrogenase/genetics* ; Pedigree

OBJECTIVETo study the effects of indium exposure on the relative content of mitochondrial ND1 gene in lymphocytes.

METHODSVenous blood was obtained from 14 healthy workers and anticoagulated with heparin. Blood lymphocytes were separated and divided into three tube cultures. For two tubes in the exposed group, indium chloride was added to final concentrations of 0.2 mmol/L and 0.8 mmol/L, respectively. For one tube in the control group, an equal volume of normal saline solution was added. After incubation for 72 h, the relative content of mitochondrial gene in each group was determined using quantitative real-time PCR.

RESULTSLymphocytes exposed to 0.8 mmol/L indium chloride had a significantly higher relative content of mitochondrial gene than those exposed to 0.2 mmol/L indium chloride and those in the control group (P < 0.05, P < 0.05).

CONCLUSIONLymphocytes exposed to a high concentration of indium and its compounds have an elevated relative content of mitochondrial ND1 gene, indicating increased oxidative DNA damage induced by exposure to a high concentration of indium and its compounds.

DNA Damage ; drug effects ; DNA, Mitochondrial ; genetics ; Humans ; Indium ; toxicity ; Lymphocytes ; drug effects ; NADH Dehydrogenase ; genetics ; Occupational Exposure

OBJECTIVETo investigate the role of MT-ND1 m.3635G>A mutation in the pathogenesis of Leber's hereditary optic neuropathy (LHON).

METHODSBiochemical characteristics including the activity of complex Ⅰ, ATP production and oxygen consumption rate among lymphoblastoid cell lines derived from 3 carriers, 3 affected matrilineal relatives of the families and 3 controls were compared.

RESULTSComparison of mitochondrial functions in lymphoblastoid cell lines of the carriers, patients and controls showed a 51.0% decrease in the activity of complex Ⅰ in patients compared with controls (P<0.05). The m.3635G>A mutation has resulted in decreased efficiency of ATP synthesis (P<0.05). Comparison of oxygen consumption rate showed that the basal OCR (P<0.05), ATP-linked OCR (P<0.05) and the maximum OCR (P<0.05) have all reduced to some extent compared with the controls.

CONCLUSIONThese results showed that m.3635G>A, as a LHON-associated mutation, can lead to mitochondrial dysfunction.

Adenosine Triphosphate ; genetics ; Asian Continental Ancestry Group ; genetics ; Female ; Humans ; Male ; Mitochondria ; genetics ; Mutation ; genetics ; NADH Dehydrogenase ; genetics ; Optic Atrophy, Hereditary, Leber ; genetics ; Pedigree

OBJECTIVE: To test droplet digital PCR for species identification and absolute quantification of biological sample. METHODS: Specific primers and probes for human mtDNA encoding gene ND4 and 16S rRNA were designed, and the species-specificity was assessed on DNA samples derived from human and common animals. To determine the sensitivity and stability of droplet digital PCR for species identification and absolute quantification, gradient dilution series of recombinant plasmid and 16 human DNA samples were analyzed. RESULTS: Human recombinant plasmid FAM (ND4) could be used in detecting the samples of human. And the results of detecting were consistent with all levels of diluted concentrations. Droplet digital PCR was able to detect low and single copy of target DNA. CONCLUSION Droplet digital PCR, with high sensitivity and specificity, is fully amenable for species identification and absolute quantification of biological samples, also it can be applied on routine forensic examination.
Animals ; DNA ; DNA Primers/genetics* ; DNA, Mitochondrial/genetics* ; Humans ; NADH Dehydrogenase/genetics* ; Polymerase Chain Reaction/methods* ; RNA, Ribosomal, 16S/genetics* ; Sensitivity and Specificity ; Species Specificity

OBJECTIVETo investigate the relationship of the mutational status of the ND4 gene and the clinical features of acute myelogenous leukemia (AML) patients with ND4 mutations.

METHODSUsing PCR combined with directly sequencing, we identified somatic mutations of ND4 in 121 primary AML patients to couple with their clinical features.

RESULTSThere were 58 male patients and 63 female patients (median age 49 years, 10-86 years). Eight of 121 patients (6.6%) with de novo AML were found harboring missense mutation of ND4 gene, including 3 patients with A131V (3/8, 37.5%), 2 patients with A404T (2/8, 25%), 1 patient with F149L (1/8, 12.5%), 1 patient with G242D (1/8, 12.5%) and 1 patient with Y409H (1/8, 12.5%), respectively. Patients with ND4 mutations were associated with good karyotype (P=0.049), regardless of gender, age, white blood cell, hemoglobin, platelet, blast cells of bone marrow or immunophenotype (P>0.05). There were no statistical significance in mutations of FLT3-ITD, NPM1, CEBPA, c-KIT and DNMT3A between patients with ND4 mutation and wild-type (wt) ND4 (P>0.05). The median overall survival of patients with ND4 mutations and wt ND4 were all not reached. The median relapse-free survival were not reached and 29(2-53) months, respectively (P>0.05). There was no significance in the ratio of CR and RR patients between wt ND4 and ND4 mutated groups (P>0.05).

CONCLUSIONIt was concluded that novel ND4 mutations could be found in de novo AML patients, especially in patients with good karyotype. Thus, ND4 mutations might play an important role in AML prognosis. However, whether the mitochondria dysfunction contribute to leukemogenesis needs to be further investigated.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; Female ; Humans ; Leukemia, Myeloid, Acute ; drug therapy ; genetics ; Male ; Middle Aged ; Mutation ; NADH Dehydrogenase ; genetics ; Prognosis ; Young Adult

OBJECTIVETo clone and screen genes related to multidrug resistance (MDR) in leukemia.

METHODSSuppression subtractive hybridization (SSH) was performed to profile differentially expressed genes between a MDR leukemia cell line (K562/DOX, as tester) and its parent cell line (K562, as driver). Reverse Northern dot blot was carried out to further screen the subtracted cDNA library. The overexpressed cDNA fragments in K562/DOX cells were sequenced and compared with known genes in Genbank. RT-PCR and Northern blot were employed to confirm the differential expression of some identified genes.

RESULTSEleven genes were identified being overexpressed in K562/DOX, including S3 ribosomal protein (S3rp) gene, NADH dehydrogenase subunit 2 (ND2) gene and My023 gene, which have not been reported to be related to MDR in cancer.

CONCLUSIONSeveral genes, which might be involved in MDR were identified, indicating novel mechanisms of MDR in leukemia.

Blotting, Northern ; Drug Resistance, Multiple ; genetics ; Drug Resistance, Neoplasm ; genetics ; Gene Library ; Genes, MDR ; genetics ; Humans ; K562 Cells ; Leukemia ; genetics ; NADH Dehydrogenase ; genetics ; Nucleic Acid Hybridization ; methods ; Reverse Transcriptase Polymerase Chain Reaction ; Ribosomal Proteins ; genetics

We describe a Korean family presenting with pediatric-onset, progressive, generalized dystonia with bilateral striatal necrosis and the homoplasmic G14459A mutation in the mitochondrial ND6 gene. The G14459A mutation has been reported in families presenting with Leber hereditary optic neuropathy (LHON) alone, LHON plus dystonia, or pediatric-onset dystonia. The proband had shown dysarthria, progressive generalized dystonia, and spasticity at 5 yr. Brain MRI demonstrated bilateral striatal necrosis. Additional investigation of family members revealed the presence of homoplasmic G14459A mutation in asymptomatic individuals. The clinical manifestation of the homoplasmic G14459A mtDNA mutation within the same family showed asymptomatic or pediatric-onset dystonia, without optic neuropathy. This study reemphasizes that the G14459A mutation is a candidate mutation for maternally inherited dystonia, regardless of optic neuropathy, and supports the hypothesis that nuclear genes may play a role in modifying the clinical expression of mitochondrial disease.
Adult ; Asian Continental Ancestry Group/*genetics ; Base Sequence ; Brain/pathology ; Dystonia/complications/diagnosis/*genetics ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Mitochondrial Diseases/complications/diagnosis/*genetics ; NADH Dehydrogenase/*genetics ; Necrosis ; Optic Atrophy, Hereditary, Leber/genetics ; Pedigree ; *Point Mutation ; Republic of Korea

OBJECTIVETo report on the clinical, genetic and molecular characteristics of three ethnic Han Chinese families affected with Leber's hereditary optic neuropathy (LHON).

METHODSThe three families were all diagnosed with LHON. Ophthalmologic examinations were conducted on the probands . The ND1, ND4 and ND6 genes of the mitochondrial DNA (mtDNA) were amplified with PCR respectively for the screening of three primary mutations G3460A, G11778A and T14484C. The entire mtDNA of the probands were also amplified by PCR.

RESULTSAnalysis of mtDNA in the three pedigrees has failed to find the presence of the three LHON associated mutations but presence of a homoplastic ND1 T3866C mutation in all probands and their matrilineal relatives . The probands had different levels of visual impairment. The penetrance in the three families has been calculated as 12.5%, 11.1% and 33.3%, respectively. The T3866C mutation has resulted in replacement of isoleucine at position 187 with theronine. The isoleucine at position 187 is located at one of the transmembrane domains of ND1 polypeptide.

CONCLUSIONAbove results have suggested that the ND1 T3866C mutation might have been involved in the pathogenesis of LHON in the three Chinese families studied.

Adolescent ; Asian Continental Ancestry Group ; ethnology ; genetics ; Base Sequence ; Child ; Female ; Humans ; Male ; Mitochondria ; genetics ; Molecular Sequence Data ; NADH Dehydrogenase ; genetics ; Optic Atrophy, Hereditary, Leber ; ethnology ; genetics ; Pedigree ; Point Mutation

OBJECTIVETo assess the prevalence of the A to G variant at nucleotide 12026 (mt12026) of the mitochondrial NADH-dehydrogenase subunit 4 (ND4) gene in familial diabetes mellitus in Chinese population.

METHODSThe authors screened 770 randomly selected, unrelated probands of diabetic pedigrees, and 309 controls with normal glucose tolerance for the variant by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique and PCR-direct-sequencing.

RESULTSThe mt12026 A --> G variant was detected in 28 diabetic patients (3.63%) and 9 controls (2.91%). The frequency of the variant mt12026 A --> G was not statistically different between diabetic patients and controls. Moreover, clinical characteristics such as age, body mass index (BMI), and insulin resistant index were not different between diabetic patients with and without the mt12026 mutation.

CONCLUSIONThe mt12026 A --> G variant is a mitochondrial gene polymorphism in Chinese population, and it is unlikely that the mutation is in itself the cause of diabetes.

Asian Continental Ancestry Group ; genetics ; Blood Glucose ; metabolism ; Body Mass Index ; China ; DNA, Mitochondrial ; chemistry ; genetics ; Diabetes Mellitus ; blood ; ethnology ; genetics ; Family Health ; Female ; Gene Frequency ; Humans ; Male ; Middle Aged ; NADH Dehydrogenase ; genetics ; Point Mutation ; Polymorphism, Genetic ; Sequence Analysis, DNA

Opisthorchis viverrini and Clonorchis sinensis are parasites known to be carcinogenic and causative agents of cholangiocarcinoma in Asia. The standard method for diagnosis for those parasite infections is stool examination to detect parasite eggs. However, the method has low sensitivity, and eggs of O. viverrini and C. sinensis are difficult to distinguish from each other and from those of some other trematodes. Here, we report a multiplex real-time PCR coupled with high resolution melting (HRM) analysis for the differentiation of O. viverrini and C. sinensis eggs in fecal samples. Using 2 pairs of species-specific primers, DNA sequences from a portion of the mitochondrial NADH dehydrogenase subunit 2 (nad 2) gene, were amplified to generate 209 and 165 bp products for O. viverrini and C. sinensis, respectively. The distinct characteristics of HRM patterns were analyzed, and the melting temperatures peaked at 82.4+/-0.09degrees C and 85.9+/-0.08degrees C for O. viverrini and C. sinensis, respectively. This technique was able to detect as few as 1 egg of O. viverrini and 2 eggs of C. sinensis in a 150 mg fecal sample, which is equivalent to 7 and 14 eggs per gram of feces, respectively. The method is species-specific, rapid, simple, and does not require fluorescent probes or post-PCR processing for discrimination of eggs of the 2 species. It offers a new tool for differentiation and detection of Asian liver fluke infections in stool specimens.
Animals ; Asia ; Clonorchis sinensis/*classification/*genetics/isolation & purification ; Feces/parasitology ; Humans ; Multiplex Polymerase Chain Reaction/*methods ; NADH Dehydrogenase/genetics ; Opisthorchis/*classification/*genetics/isolation & purification ; Parasitology/*methods ; Real-Time Polymerase Chain Reaction/*methods ; Sensitivity and Specificity ; Transition Temperature ; Zygote