In recent years, the roles of mitochondrial RNA and its associated human diseases have been reported to increase significantly. Treatments based on mtRNA metabolic processes and nuclear gene mutations are thus discussed. The mitochondrial oxidative phosphorylation process is affected by mtRNA metabolism, including mtRNA production, maturation, stabilization, and degradation, which leads to a variety of inherited human mitochondrial diseases. Moreover, mitochondrial diseases are caused by mitochondrial messenger RNA, mitochondrial transfer RNA, and mitochondrial ribosomal RNA gene mutations. This review presents the molecular mechanisms of human mtRNA metabolism and pathological mutations in mtRNA metabolism-related nuclear-encoded/nonencoded genes and mitochondrial DNA mutations to highlight the importance of mitochondrial RNA-related diseases and treatments.
Humans ; Mitochondrial Diseases/therapy* ; RNA, Mitochondrial ; RNA/genetics* ; Mitochondria/genetics* ; Mutation/genetics* ; RNA, Transfer/genetics* ; DNA, Mitochondrial/genetics*

OBJECTIVE: To explore mechanisms of acid-sensing ion channel 1 (ASIC1) mediated lumbar nucleus pulposus cell apoptosis through extracellular-signalregulated protein kinase 5 (ERK5) signaling pathway and mitochondrial dysfunction pathway. METHODS: Totally 34 patients with degenerative lumbar disc herniation (LDH) admitted from January 2020 to December 2022 were collected as research objects, including 21 males and 13 females;aged from 29 to 52 years old with an average of (37.43±4.75) years old;22 patients with grade Ⅱ and 12 patients with grade Ⅳ, according to Pfirrmann grading criteria;15 patients with L_4,5 and 19 patients with L₅S₁. The expression of ASIC1 in nucleus pulposus of LDH patients was measured by immunohistochemical staining. Nucleus pulposus cells were cultured by primary culture method, identified by toluidine blue staining and immunohistochemical staining, and the expression of ASIC1 protein was located by immunofluorescence staining. According to the addition of siRNA-ASIC1, ASIC1 overexpression plasmid, and ERK5 inhibitors, the nucleus pulpocyte was divided into three groups, named as SIRNA-silenced group, overexpression group, and inhibitor group, with 3 patients in each group. Cells of each group were collected at 72 h after intervention, expression of ASIC1, ERK5, BCL-xL/BCL-2-associated Death promoter (Bad), B-cell lymphoma-2 associated X (Bax) and B-cell lymphoblast-2 gene (Bcl-2) were detected by reverse transcription-polymerase chain reaction (RT-PCR);intracellular calcium ion levels were detected by calcium ion kit, mitochondrial membrane potential was detected by JC-1 kit, and apoptosis was observed by AV-PI kit. RESULTS: In LDH patients with grade Ⅳ, nucleus pulposus tissue removed during operation revealed poor elasticity, white color and poor ductility, and immunohistochemical results showed increased ASIC1 expression. There was no significant difference in mRNA relative expression of ASIC1 between siRNA silencing group (0.31±0.03) and inhibitor group (0.39±0.05) (P>0.05). The mRNA relative expression level of ERK5 in siRNA silencing group(0.32±0.05) was significantly higher than that in inhibitor group (0.15±0.04)(P<0.05), which suggested ERK5 was the downstream molecule of ASIC1. The mRNA relative expression levels of apoptosis promoting factor Bad and Bax in siRNA silencing group and inhibitor group were lower than those in overexpression group(P<0.05), the relative expression level of anti-apoptosis factor Bcl-2 mRNA was significantly increased (P<0.05). The calcium content in overexpression group was higher than that in siRNA silencing and inhibitor groups (P<0.05), the normal proportion of mitochondrial membrane potential in overexpression group was lower than that in siRNA silencing and inhibitor group (P<0.05), and the apoptosis rate in overexpression group was higher than that in siRNA silencing and inhibitor group (P<0.05). CONCLUSION After the activation of ASIC1 channel protein, calcium ions could enter the cells and act as a second messenger molecule to regulate apoptosis of nucleus pulposus cells by ERK5 signaling pathway and mitochondrial disorder pathway.
Humans ; Acid Sensing Ion Channels/physiology* ; Male ; Female ; Apoptosis ; Middle Aged ; Adult ; Signal Transduction ; Mitogen-Activated Protein Kinase 7/physiology* ; Mitochondrial Diseases/genetics* ; Nucleus Pulposus/metabolism* ; Intervertebral Disc Degeneration/metabolism* ; Mitochondria/metabolism* ; Intervertebral Disc Displacement/genetics*

OBJECTIVES: To investigate the clinical features and gene mutation characteristics of combined oxidative phosphorylation deficiency type 7 (COXPD7) caused by mutations in the C12orf65 gene, and to enhance the awareness of this disease. METHODS: A child diagnosed with COXPD7 in the Department of Neurology, Children's Hospital Affiliated to Zhengzhou University in 2021 was included, along with 10 patients reported in the literature. All subjects were analyzed for their genotypes and clinical phenotypes. RESULTS: A total of 11 patients with COXPD7 were included, comprising 1 reported in this study and 10 from the literature. Among the 11 patients, 9 had homozygous mutations in the C12orf65 gene, while 2 had compound heterozygous mutations, which were identified as frameshift or nonsense mutations. The age of onset ranged from 1 day to 2 years, and clinical manifestations included optic nerve atrophy and delays in intellectual and motor development. Eight patients exhibited external ophthalmoplegia, and five patients displayed spastic paralysis. Cranial magnetic resonance imaging revealed optic nerve atrophy in all 11 patients, abnormal brainstem signals in 10 patients, and a lactate peak on brainstem magnetic resonance spectroscopy scans in 3 patients. CONCLUSIONS COXPD7 associated with the C12orf65 gene results from homozygous or compound heterozygous mutations, with primary clinical manifestations of optic nerve atrophy and delays in intellectual and motor development. Some patients may also present with spastic paralysis or external ophthalmoplegia. Cranial imaging reveals symmetrical abnormal signals in bilateral basal ganglia and brainstem, and a lactate peak is observed on brainstem magnetic resonance spectroscopy scans.
Child, Preschool ; Female ; Humans ; Infant ; Male ; Mitochondrial Diseases/genetics* ; Mitochondrial Proteins/genetics* ; Mutation ; Oxidative Phosphorylation ; Infant, Newborn

OBJECTIVE: To analyze the clinical phenotype and genetic variants of a child suspected for mitochondrial F-S disease. METHODS: A child with mitochondrial F-S disease who visited Department of Neurology, Hunan Provincial children's Hospital on November 5, 2020 was selected as research subject of this study. Clinical data of the child was collected. The child was subjected to whole exome sequencing (WES). Bioinformatics tools were used to analyze the pathogenic variants. Candidate variants were verified by Sanger sequencing of the child and her parents. RESULTS: WES revealed that the child has harbored compound heterozygous variants of the FDXR gene, namely c.310C>T (p.R104C) and c.235C>T (p.R79C), which were inherited from her father and mother, respectively. Neither variant has been reported in HGMD, PubMed, 1000 Genomes, and dbSNP databases. Both of the variants have been suggested as deleterious according to the prediction results from different bioinformatics analysis software. CONCLUSION Mitochondrial diseases should be suspected for patients with multiple system involvement. The compound heterozygous variants of the FDXR gene probably underlay the disease in this child. Above finding has enriched the spectrum of FDXR gene mutations underlying mitochondrial F-S disease. WES can facilitate the diagnosis of mitochondrial F-S disease at the molecular level.
Female ; Humans ; Exome Sequencing ; Mitochondrial Diseases/genetics* ; Mothers ; Mutation ; Phenotype ; Child

Humans ; Mitochondrial Diseases/prevention & control* ; DNA, Mitochondrial/genetics*

Humans ; Mitochondrial Diseases/therapy* ; DNA, Mitochondrial/genetics*

OBJECTIVE: To determine the carrier rate for 21 inherited metabolic diseases among a Chinese population of childbearing age. METHODS: A total of 897 unrelated healthy individuals (including 143 couples) were recruited, and DNA was extracted from their peripheral blood samples. Whole exome sequencing (WES) was carried out to screen potential variants among 54 genes associated with 21 inherited metabolic diseases. Pathogenic and likely pathogenic variants and unreported loss-of-function variants were analyzed. RESULTS: One hundred fourty types of pathogenic/likely pathogenic variants (with an overall number of 183) and unreported loss-of-function variants were detected, which yield a frequency of 0.20 per capita. A husband and wife were both found to carry pathogenic variants of the SLC25A13 gene and have given birth to a healthy baby with the aid of preimplantation genetic diagnosis. The detected variants have involved 40 genes, with the most common ones including ATP7B, SLC25A13, PAH, CBS and MMACHC. Based on the Hardy-Weinberg equilibrium, the incidence of the 21 inherited metabolic diseases in the population was approximately 1/1100, with the five diseases with higher incidence including citrullinemia, methylmalonic acidemia, Wilson disease, glycogen storage disease, and phenylketonuria. CONCLUSION This study has preliminarily determined the carrier rate and incidence of 21 inherited metabolic diseases among a Chinese population of childbearing age, which has provided valuable information for the design of neonatal screening program for inherited metabolic diseases. Pre-conception carrier screening can provide an important measure for the prevention of transmission of Mendelian disorders in the population.
Asians/genetics* ; China ; Exome ; Female ; Humans ; Infant, Newborn ; Metabolic Diseases/genetics* ; Mitochondrial Membrane Transport Proteins/genetics* ; Oxidoreductases/genetics* ; Whole Exome Sequencing

OBJECTIVE: To analyze the clinical features and genetic variants in four neonates with very long chain acyl-coenzyme A dehydrogenase (VLCAD) deficiency. METHODS: Neonates with a tetradecenoylcarnitine (C14:1) concentration at above 0.4 μmol/L in newborn screening were recalled for re-testing. Four neonates were diagnosed with VLCAD deficiency by MS-MS and genetic testing, and their clinical features and genotypes were analyzed. RESULTS: All cases had elevated blood C14:1, and the values of first recalls were all lower than the initial test. In 2 cases, the C14:1 had dropped to the normal range. 1 case has remained at above 1 μmol/L after the reduction, and the remainder one case was slightly decreased. In total eight variants of the ADACVL genes were detected among the four neonates, which included 5 missense variants and 3 novel variants (p.Met344Val, p.Ala416Val, c.1077+6T>A). No neonate showed salient clinical manifestations. CONCLUSION Above findings have enriched the spectrum of ADACVL gene mutations and provided a valuable reference for the screening and diagnosis of VLCAD deficiency.
Acyl-CoA Dehydrogenase/genetics* ; Acyl-CoA Dehydrogenase, Long-Chain ; Congenital Bone Marrow Failure Syndromes ; Genetic Testing ; Humans ; Infant, Newborn ; Lipid Metabolism, Inborn Errors ; Mitochondrial Diseases ; Muscular Diseases ; Tandem Mass Spectrometry

OBJECTIVE: To explore the genetic basis for a child with myopathy and cerebellar atrophy with ataxia. METHODS: Clinical examinations and laboratory testing were carried out for the patient. The proband and the parents' genomic DNA was extracted from peripheral blood samples and subjected to trio whole-exome sequencing. Candidate variant was validated by Sanger sequencing. RESULTS: The 1-year-and-8-month-old boy manifested motor developmental delay, ataxia, hypomyotonia, increased serum creatine kinase. Cranial MRI showed cerebellar atrophy with progressive aggravation. Genetic testing revealed that the patient has harbored compound heterozygous variants of the MSTO1 gene, namely c.13delG (p.Ala5ProfsTer68) and c.971C>T (p.Thr324Ile), which were respectively inherited from his mother and father. The former was unreported previously and was predicted to be likely pathogenic, whilst the latter has been reported previously and was predicted to be of uncertain significance. CONCLUSION The compound heterozygous c.13delG (p.Ala5ProfsTer68) and c.971C>T (p.Thr324Ile) variants probably underlay the disease in the proband. Above finding has enriched the spectrum of MSTO1 gene variants underlying mitochondrial myopathy and cerebellar atrophy with ataxia.
Ataxia/genetics* ; Atrophy/genetics* ; Cell Cycle Proteins/genetics* ; Child ; Cytoskeletal Proteins/genetics* ; Humans ; Infant ; Male ; Mitochondrial Myopathies ; Mutation ; Neurodegenerative Diseases ; Whole Exome Sequencing

Objective: To explore the clinical features of hepatocerebral mitochondrial DNA depletion syndrome (MDS). Methods: The clinical data of 6 hepatocerebral MDS patients diagnosed in the Jinshan Hospital of Fudan University from January 2012 to December 2019 were retrospectively collected and analyzed. Related literature published before January 2020 were searched with the key words of "DGUOK""MPV17""POLG""C10orf2" in PubMed, China national knowledge infrastructure (CNKI) and Wanfang database. Results: All the 6 hepatocerebral MDS cases were male. The age of onset ranged from 3 days to 8 months. The most common initial symptoms were cholestasis and developmental retrogression. The main clinical manifestations included hepatomegaly (4 cases), hypotonia (3 cases), growth retardation (4 cases), cholestasis (5 cases), coagulopathy (5 cases), hypoalbuminemia (3 cases), hypoglycemia (4 cases), hyperlactacidemia (5 cases), and abnormal blood metabolism screening (6 cases). The isotope hepatobiliary imaging revealed no gallbladder and intestinal tract development within 24 hours in 2 patients. Regarding the cranial imaging examination, the head CT found widening of the extracranial space in 1 case, the brain magnetic resonance imaging (MRI) found ventricular enlargement in 2 cases, and the brain ultrasound found peripheral white matter injury in 1 case. Two cases were lost to follow-up, one died of liver failure, and three died of multiple organ failure due to aggravated infection. Among the 6 cases, there were 3 with MPV17 variation (c.182T>C and c.279G>C were novel), 1 with POLG variation (c.2993G>A was novel), 1 with DGUOK variation (c.679G>A homozygous mutation, parthenogenetic diploid of chromosome 2) and 1 with C10orf2 variation (c.1186C>T and c.1504C>T were novel). The literature review found that 129, 100, 51 and 12 cases of hepatocerebral MDS were caused by DGUOK, MPV17, POLG and C10orf2 gene variations, respectively. And the most common clinical manifestations were liver dysfunction presented with cholestasis and elevated transaminase, metabolic disorders including hypoglycemia and hyperlactacidemia, and diverse neurologic symptoms including developmental retardation, hypotonia, epilepsy and peripheral neuropathy. Besides, 1/3 of the patients with C10orf2 variation developed renal tubular injury. Conclusions: Hepatocerebral MDS mainly present with liver dysfunction, metabolic disorder and neuromuscular impairment. Different genotypes show specific clinical manifestations.
Cholestasis ; DNA, Mitochondrial/genetics* ; Female ; Humans ; Hypoglycemia/genetics* ; Infant ; Liver Diseases/genetics* ; Male ; Mitochondrial Diseases ; Muscle Hypotonia ; Retrospective Studies