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1.
J Med Genet ; 2021 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-33811136

RESUMEN

BACKGROUND: Progressive cavitating leukoencephalopathy (PCL) is thought to result from mutations in nuclear genes affecting mitochondrial function and energy metabolism. To date, mutations in two subunits of complex I, NDUFS1 and NDUFV1, have been reported to be related to PCL. METHODS: Patients underwent clinical examinations, brain MRI, skin biopsy and muscle biopsy. Whole-genome or whole-exome sequencing was performed on the index patients from two unrelated families with PCL. The effects of the mutations were examined through complementation of the NDUFV2 mutation by cDNA expression. RESULTS: The common clinical features of the patients in this study were recurring episodes of acute or subacute developmental regression that appeared in the first years of life, followed by gradual remissions and prolonged periods of stability. MRI showed leukoencephalopathy with multiple cavities. Three novel NDUFV2 missense mutations were identified in these families. Complex I deficiency was confirmed in affected individuals' fibroblasts and a muscle biopsy. Functional and structural analyses revealed that these mutations affect the structural stability and function of the NDUFV2 protein, indicating that defective NDUFV2 function is responsible for the phenotypes in these individuals. CONCLUSIONS: Here, we report the clinical presentations, neuroimaging and molecular and functional analyses of novel mutations in NDUFV2 in two sibling pairs of two Chinese families presenting with PCL. We hereby expand the knowledge on the clinical phenotypes associated with mutations in NDUFV2 and the genotypes causative for PCL.

2.
Sci Rep ; 11(1): 3531, 2021 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-33574353

RESUMEN

Prenatal diagnoses of mitochondrial diseases caused by defects in nuclear DNA (nDNA) or mitochondrial DNA have been reported in several countries except for Japan. The present study aimed to clarify the status of prenatal genetic diagnosis of mitochondrial diseases caused by nDNA defects in Japan. A comprehensive genomic analysis was performed to diagnose more than 400 patients, of which, 13 families (16 cases) had requested prenatal diagnoses. Eight cases diagnosed with wild type homozygous or heterozygous variants same as either of the heterozygous parents continued the pregnancy and delivered healthy babies. Another eight cases were diagnosed with homozygous, compound heterozygous, or hemizygous variants same as the proband. Of these, seven families chose to terminate the pregnancy, while one decided to continue the pregnancy. Neonatal- or infantile-onset mitochondrial diseases show severe phenotypes and lead to lethality. Therefore, such diseases could be candidates for prenatal diagnosis with careful genetic counseling, and prenatal testing could be a viable option for families.

3.
Mitochondrion ; 57: 222-229, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33401012

RESUMEN

Childhood-onset dystonia with optic atrophy and basal ganglia abnormalities is an extremely rare autosomal recessive mitochondrial disease caused by biallelic mutations in MECR. Using whole-exome sequencing, we identified a novel homozygous MECR mutation (c.910G > T, p.Asp304Tyr) in a Chinese patient with childhood-onset dystonia and basal ganglia abnormalities, without optic atrophy. With lipoic acid treatment, the disease progression was under control, and neither visual impairment nor optic atrophy was observed. To our knowledge, this is the first study about MECR-related mitochondrial disease in a Chinese patient and the first to report that supplementation with lipoic acid is a possible effective therapeutic strategy for this disease.

4.
Mol Genet Genomic Med ; 8(10): e1427, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32749073

RESUMEN

BACKGROUND: Mitochondrial DNA depletion syndrome (MTDPS) is part of a group of mitochondrial diseases characterized by a reduction in mitochondrial DNA copy number. Most MTDPS is caused by mutations in genes that disrupt deoxyribonucleotide metabolism. METHODS: We performed the whole-exome sequencing of a hepato-encephalopathy patient with MTDPS and functional analyses to determine the clinical significance of the identified variant. RESULTS: Here, whole-exome sequencing of a patient presenting with hepato-encephalopathy and MTDPS identified a novel homozygous frameshift variant, c.13_29del (p.Trp6Profs*71) in MICOS13. MICOS13 (also known as QIL1, MIC13, or C19orf70) is a component of the MICOS complex, which plays crucial roles in the maintenance of cristae junctions at the mitochondrial inner membrane. We found loss of MICOS13 protein and fewer cristae structures in the mitochondria of fibroblasts derived from the patient. Stable expression of a wild-type MICOS13 cDNA in the patients fibroblasts using a lentivirus system rescued mitochondrial respiratory chain complex deficiencies. CONCLUSION: Our findings suggest that the novel c.13_29del (p.Trp6Profs*71) MICOS13 variant causes hepato-encephalopathy with MTDPS. We propose that MICOS13 is classified as the cause of MTDPS.

5.
Mol Genet Metab Rep ; 24: 100622, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32670798

RESUMEN

The detoxification of ammonia to urea requires a functional hepatic urea cycle, which consists of six enzymes and two mitochondrial membrane transporters. The initial step of the urea cycle is catalyzed by carbamyl phosphate synthetase 1 (CPS1). CPS1 deficiency (CPS1D) is a rare autosomal recessive disorder. N-Carbamylglutamate (NCG), a deacylase-resistant analogue of N-acetylglutamate, can activate CPS1. We describe the therapeutic course of a patient suffering from neonatal onset CPS1D with compound heterozygosity for the c.2359C > T (p.Arg787*) and c.3559G > T (p.Val1187Phe) variants in CPS1, treated with NCG. She presented with hyperammonemia, which reached 944 µmol/L at the age of 2 days. The ammonia concentration decreased after treatment with continuous hemodiafiltration, NCG, sodium benzoate, sodium phenylbutyrate, L-arginine, vitamin cocktail (vitamin B1, vitamin B12, vitamin C, vitamin E, biotin), l-carnitine, coenzyme Q10, and parenteral nutrition. Her ammonia and glutamine levels remained low; thus, protein intake was increased to 1.2 g/kg/day. Furthermore, the amount of sodium benzoate and sodium phenylbutyrate were reduced. She remained metabolically stable and experienced no metabolic crisis following treatment with oral NCG, sodium benzoate, sodium phenylbutyrate, citrulline, vitamin cocktail, l-carnitine, and coenzyme Q10 until she underwent liver transplantation at 207 days of age. She had no neurological complications at the age of 15 months. Ammonia and glutamine levels of the patient were successfully maintained at a low level via NCG treatment with increased protein intake, which led to normal neurological development. Thus, undiagnosed urea cycle disorders should be treated rapidly with acute therapy including NCG, which should be maintained until a genetic diagnosis is reached. It is essential to prevent metabolic crises in patients with CPS1D until liver transplantation to improve their prognoses.

6.
Orphanet J Rare Dis ; 15(1): 169, 2020 07 24.
Artículo en Inglés | MEDLINE | ID: mdl-32703289

RESUMEN

BACKGROUND: Hepatocerebral mitochondrial DNA depletion syndrome (MTDPS) is a disease caused by defects in mitochondrial DNA maintenance and leads to liver failure and neurological complications during infancy. Liver transplantation (LT) remains controversial due to poor outcomes associated with extrahepatic symptoms. The purposes of this study were to clarify the current clinical and molecular features of hepatocerebral MTDPS and to evaluate the outcomes of LT in MTDPS patients in Japan. RESULTS: We retrospectively assessed the clinical and genetic findings, as well as the clinical courses, of 23 hepatocerebral MTDPS patients from a pool of 999 patients who were diagnosed with mitochondrial diseases between 2007 and 2019. Causative genes were identified in 18 of 23 patients: MPV17 (n = 13), DGUOK (n = 3), POLG (n = 1), and MICOS13 (n = 1). Eight MPV17-deficient patients harbored c.451dupC and all three DGUOK-deficient patients harbored c.143-307_170del335. The most common initial manifestation was failure to thrive (n = 13, 56.5%). The most frequent liver symptom was cholestasis (n = 21, 91.3%). LT was performed on 12 patients, including nine MPV17-deficient and two DGUOK-deficient patients. Among the 12 transplanted patients, five, including one with mild intellectual disability, survived; while seven who had remarkable neurological symptoms before LT died. Five of the MPV17-deficient survivors had either c.149G > A or c.293C > T. CONCLUSIONS: MPV17 was the most common genetic cause of hepatocerebral MTDPS. The outcome of LT for MTDPS was not favorable, as previously reported, however, patients harboring MPV17 mutations associated with mild phenotypes such as c.149G > A or c.293C > T, and exhibiting no marked neurologic manifestations before LT, had a better prognosis after LT.

7.
Mol Genet Metab Rep ; 24: 100610, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32509533

RESUMEN

Mitochondrial trifunctional protein (TFP) deficiency is a rare inherited metabolic disorder caused by defects in fatty acid ß-oxidation (FAO) of long-chain fatty acids, leading to impaired energy production. Fasting avoidance, fatty acid-restricted diets, and supplementation with medium-chain triglycerides are recommended as a treatment, but there are no pharmaceutical treatments available with strong evidence of efficacy. Bezafibrate, which enhances the transcription of FAO enzymes, is a promising therapeutic option for FAO disorders (FAODs). The effectiveness of bezafibrate for FAODs has been reported in some clinical trials, but few clinical studies have investigated its in vivo efficacy toward TFP deficiency. Herein, we describe two Japanese patients with TFP deficiency. Patient 1 presented with recurrent myalgia since the age of 5 years. Laboratory findings showed increased serum levels of long-chain fatty acids and reduced expression of TFPα and TFPß in his skin fibroblasts. Based on these findings, he was diagnosed with the myopathic type of TFP deficiency. Patient 2 suddenly exhibited cardiopulmonary arrest one day after birth. Elevated levels of creatine kinase and long-chain acylcarnitines were observed. Genetic analysis identified compound heterozygous variants in HADHB (c.1175C>T/c.1364T>G). He was diagnosed with the lethal type of TFP deficiency. Although both patients were treated with dietary therapy and l-carnitine supplementation, they experienced frequent myopathic attacks associated with respiratory infections and exercise. After the initiation of bezafibrate, their myopathic manifestations were markedly reduced, leading to an improvement in quality of life without any side effects. Our clinical findings indicate that bezafibrate combined with other treatments such as dietary therapy may be effective in improving myopathic manifestations in TFP deficiency.

8.
Mol Genet Metab Rep ; 24: 100612, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32547926

RESUMEN

Hearing impairment is a neurological symptom of hypophosphatasia (HPP), which leads to a reduced quality of life. However, the pathomechanism of hearing impairment and the effects of asfotase alfa enzyme replacement therapy on hearing function in HPP have not been clarified. Here we report a case and present clinical data of a patient with perinatal HPP whose hearing impairment improved after asfotase alfa treatment.

9.
Clin Genet ; 98(2): 155-165, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32385911

RESUMEN

Mitochondrial complex I deficiency is caused by pathogenic variants in mitochondrial and nuclear genes associated with complex I structure and assembly. We report the case of a patient with NDUFA8-related mitochondrial disease. The patient presented with developmental delay, microcephaly, and epilepsy. His fibroblasts showed apparent biochemical defects in mitochondrial complex I. Whole-exome sequencing revealed that the patient carried a homozygous variant in NDUFA8. His fibroblasts showed a reduction in the protein expression level of not only NDUFA8, but also the other complex I subunits, consistent with assembly defects. The enzyme activity of complex I and oxygen consumption rate were restored by reintroducing wild-typeNDUFA8 cDNA into patient fibroblasts. The functional properties of the variant in NDUFA8 were also investigated using NDUFA8 knockout cells expressing wild-type or mutated NDUFA8 cDNA. These experiments further supported the pathogenicity of the variant in complex I assembly. This is the first report describing that the loss of NDUFA8, which has not previously been associated with mitochondrial disease, causes severe defect in the assembly of mitochondrial complex I, leading to progressive neurological and developmental abnormalities.

10.
Mol Genet Metab Rep ; 24: 100601, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32455116

RESUMEN

Glycogen storage disease type IV (GSD IV) is a rare inborn metabolic disorder characterized by the accumulation of amylopectin-like glycogen in the liver or other organs. The hepatic subtype may appear normal at birth but rapidly develops to liver cirrhosis in infancy. Liver pathological findings help diagnose the hepatic form of the disease, supported by analyses of enzyme activity and GBE1 gene variants. Pathology usually shows periodic acid-Schiff (PAS) positive hepatocytes resistant to diastase. We report two cases of hepatic GSD IV with pathology showing PAS positive hepatocytes that were mostly digested by diastase, which differ from past cases. Gene analysis was critical for the diagnosis. Both cases were found to have the same variants c.288delA (p.Gly97GlufsTer46) and c.1825G > A (p.Glu609Lys). These findings suggest that c.1825G > A variant might be a common variant in the non-progressive hepatic form of GSD IV.

11.
Brain Dev ; 42(7): 523-528, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32336482

RESUMEN

BACKGROUND: Riboflavin may prevent migraine episodes; however, there is limited evidence of its effectiveness in pediatric populations. This study investigated the effectiveness of riboflavin and clinical predictors of response in children with migraines. METHODS: We retrospectively reviewed data from 68 Japanese children with migraines, of whom 52 also exhibited another type of headache. Patients received 10 or 40 mg/day of riboflavin. We evaluated the average migraine frequency per month as a baseline and after 3 months of riboflavin therapy to determine the effectiveness and clinical predictors of response. RESULTS: The frequency of migraine episodes was significantly lower at 3 months than at baseline (median, [interquartile range], 5.2 (3-7) vs. 4.0 (2-5); p < 0.01). Twenty-five patients (36.7%) showed 50% or greater reduction in episode frequency (responders), while 18 (26.5%) showed a 25%-50% reduction. We compared responders (n = 25) and non-responders (n = 43) and found no significant differences in sex, familial history, riboflavin dose, migraine type (i.e., presence or absence of aura), age at headache onset, or age at consultation. However, non-responders were more likely to have co-morbid non-migraine headaches (odds ratio, 4.11; 95% confidence interval [CI], 1.27-13.33; p = 0.02); this variable was also significant in a multivariate analysis (adjusted odds ratio, 3.8; 95% CI, 1.16-12.6; p = 0.03). Of the co-morbid headache types, only tension headaches were significant (odds ratio, 0.176; 95% CI, 0.04-0.73; p = 0.013). No adverse effects of riboflavin were identified. CONCLUSIONS: Low-dose riboflavin is safe and modestly effective for migraines in children. It may be especially beneficial for children without other co-morbid headache types.

12.
Eur J Med Genet ; 63(5): 103872, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32028043

RESUMEN

Microdeletions in the 9q22.3 chromosomal region can cause macrosomia with characteristic features, including prenatal-onset overgrowth, metopic craniosynostosis, hydrocephalus, developmental delay, and intellectual disability, in addition to manifestations of nevoid basal cell carcinoma syndrome (NBCCS). Haploinsufficiency of PTCH1 may be responsible for accelerated overgrowth, but the mechanism of macrosomia remains to be elucidated. We report a familial case with a 9q22.3 microdeletion, manifesting with prenatal-onset overgrowth in a mother and post-natal overgrowth in her daughter. Although both were clinically diagnosed with NBCCS, they had characteristic features of 9q22.3 microdeletion, especially the daughter. Microarray comparative genomic hybridization analysis revealed a 4.0 Mb deletion of chromosome 9q22.3 in both individuals. Among the 11 reported patients of overgrowth and/or macrosomia, a 550 Kb region encompassing PTCH1, C9orf3, FANCC, and 5 miRNAs is the most commonly deleted region. The let-7 family miRNAs, which are involved in diverse cellular processes including growth and tumor processes, were identified in the deleted regions in 10 of 11 patients. Characteristic features of 9q22.3 microdeletion might be associated with decreased expression of let-7.

13.
J Inherit Metab Dis ; 43(4): 819-826, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-31967322

RESUMEN

Leigh syndrome is a major phenotype of mitochondrial diseases in children. With new therapeutic options being proposed, assessing the mortality and clinical condition of Leigh syndrome patients is crucial for evaluating therapeutics. As data are scarce in Japan, we analysed the mortality rate and clinical condition of Japanese Leigh syndrome patients that we diagnosed since 2007. Data from 166 Japanese patients diagnosed with Leigh syndrome from 2007 to 2017 were reviewed. Patients' present status, method of ventilation and feeding, and degree of disability as of April 2018 was analysed. Overall, 124 (74.7%) were living, 40 (24.1%) were deceased, and 2 (1.2%) were lost to follow-up. Median age of living patients was 8 years (1-39 years). Median length of disease course was 91 months for living patients and 23.5 months for deceased patients. Nearly 90% of deaths occurred by age 6. Mortality rate of patients with onset before 6 months of age was significantly higher than that of onset after 6 months. All patients with neonatal onset were either deceased or bedridden. MT-ATP6 deficiency caused by m.8993T>G mutation and MT-ND5 deficiency induced a severe form of Leigh syndrome. Patients with NDUFAF6, ECHS1, and SURF1 deficiency had relatively mild symptoms and better survival. The impact of onset age on prognosis varied across the genetic diagnoses. The clinical condition of many patients was poor; however, few did not require mechanical ventilation or tube-feeding and were not physically dependent. Early disease onset and genetic diagnosis may have prognostic value.

14.
J Pediatr Endocrinol Metab ; 32(10): 1181-1185, 2019 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-31473688

RESUMEN

Mitochondrial acyl-CoA dehydrogenase 9 (ACAD9) deficiency is one of the common causes of respiratory chain complex I deficiency, which is characterized by cardiomyopathy, lactic acidemia, and muscle weakness. Infantile cardiomyopathy is the most common phenotype and is usually lethal by the age of 5 years. Riboflavin treatment is known to be effective in ~65% of the patients; however, the remaining are unresponsive to riboflavin and are in need of additional treatment measures. In this report, we describe a patient with ACAD9 deficiency who developed progressive cardiomyopathy at 8 months of age. As the patient's left ventricular ejection fraction (LVEF) kept decreasing to 45.4% at 1 year 8 months, sodium pyruvate treatment was introduced together with a beta-blocker and coenzyme Q10. This resulted in a steady improvement, with full and sustained normalization of cardiac function without riboflavin. The therapy, therefore, might be a useful addition for the treatment of ACAD9 deficiency.


Asunto(s)
Acidosis/tratamiento farmacológico , Acil-CoA Deshidrogenasa/deficiencia , Acil-CoA Deshidrogenasas/deficiencia , Errores Innatos del Metabolismo de los Aminoácidos/tratamiento farmacológico , Cardiomiopatías/tratamiento farmacológico , Cardiomiopatía Hipertrófica/tratamiento farmacológico , Carvedilol/administración & dosificación , Enfermedades Mitocondriales/tratamiento farmacológico , Debilidad Muscular/tratamiento farmacológico , Piruvatos/administración & dosificación , Ubiquinona/análogos & derivados , Acidosis/complicaciones , Acidosis/patología , Antagonistas Adrenérgicos beta/administración & dosificación , Errores Innatos del Metabolismo de los Aminoácidos/complicaciones , Errores Innatos del Metabolismo de los Aminoácidos/patología , Cardiomiopatías/complicaciones , Cardiomiopatías/patología , Cardiomiopatía Hipertrófica/complicaciones , Cardiomiopatía Hipertrófica/patología , Quimioterapia Combinada , Femenino , Humanos , Recién Nacido , Enfermedades Mitocondriales/complicaciones , Enfermedades Mitocondriales/patología , Debilidad Muscular/complicaciones , Debilidad Muscular/patología , Pronóstico , Ubiquinona/administración & dosificación , Vitaminas/administración & dosificación
15.
J Med Case Rep ; 13(1): 250, 2019 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-31401974

RESUMEN

BACKGROUND: Various antiepileptic drugs can potentially cause psychiatric side effects in patients with epilepsy, but the precise mechanism of these actions remains unknown. In recent years, the common polymorphism C677T in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene has attracted attention for its role in the onset of psychiatric diseases. MTHFR and several vitamins (as cofactors) are crucial for remethylation of homocysteine via folate and homocysteine metabolism. We report a case of a Japanese patient who presented with reversible schizophrenia-like symptoms during antiepileptic drug therapy. CASE PRESENTATION: Our patient had frontal lobe epilepsy and had been treated with several antiepileptic drugs since the age of 13 years. He developed auditory hallucinations and multiple personalities at 17 years of age, several months after the initiation of phenytoin and phenobarbital, despite these antiepileptic drugs being used within the therapeutic ranges. Genetic analysis revealed that he was homozygous for the C677T polymorphism of MTHFR. Hyperhomocysteinemia, hypomethionemia, and multiple vitamin deficiencies, including folate, riboflavin, and pyridoxal, were identified at the age of 23 years. Vitamin supplementation and alteration of the antiepileptic drugs improved his psychotic symptoms. Multiple vitamin deficiencies with homozygous MTHFR C677T should be considered in patients presenting with schizophrenia-like symptoms during antiepileptic drug therapy. CONCLUSIONS: To the best of our knowledge, this is the first report of antiepileptic drug-induced psychosis associated with homozygous C677T and multiple vitamin deficiencies. Our findings will contribute to the elucidation of the pathogenesis of the psychiatric side effects of antiepileptic drugs and lead to improved medical management for patients with epilepsy.


Asunto(s)
Anticonvulsivantes/efectos adversos , Epilepsia/tratamiento farmacológico , Fenobarbital/efectos adversos , Fenitoína/efectos adversos , Psicosis Inducidas por Sustancias/etiología , Adolescente , Avitaminosis/complicaciones , Humanos , Masculino , Metilenotetrahidrofolato Reductasa (NADPH2)/deficiencia , Polimorfismo Genético , Psicosis Inducidas por Sustancias/diagnóstico , Psicosis Inducidas por Sustancias/genética , Adulto Joven
16.
Sci Rep ; 9(1): 10549, 2019 07 22.
Artículo en Inglés | MEDLINE | ID: mdl-31332208

RESUMEN

Mitochondrial respiratory chain complexes II, III, and IV and cytochrome c contain haem, which is generated by the insertion of Fe2+ into protoporphyrin IX. 5-Aminolevulinic acid (ALA) combined with sodium ferrous citrate (SFC) was reported to enhance haem production, leading to respiratory complex and haem oxygenase-1 (HO-1) upregulation. Here, we investigated the effects of different concentrations of ALA and SFC alone or in combination (ALA/SFC) on fibroblasts from 8 individuals with mitochondrial diseases and healthy controls. In normal fibroblasts, expression levels of oxidative phosphorylation (OXPHOS) complex subunits and corresponding genes were upregulated only by ALA/SFC. Additionally, the increased oxygen consumption rate (OCR) and ATP levels in normal fibroblasts were more obvious after treatment with ALA/SFC than after treatment with ALA or SFC. OXPHOS complex proteins were enhanced by ALA/SFC, whereas OCR and ATP levels were increased in 6 of the 8 patient-derived fibroblasts. Further, HO-1 protein and mRNA levels were enhanced by ALA/SFC in all fibroblasts. The relative mtDNA copy number was increased by ALA/SFC. Thus, our findings indicate that ALA/SFC is effective in elevating OXPHOS, HO-1 protein, and mtDNA copy number, resulting in an increase in OCR and ATP levels, which represents a promising therapeutic option for mitochondrial diseases.


Asunto(s)
Ácido Aminolevulínico/administración & dosificación , Compuestos Ferrosos/administración & dosificación , Enfermedades Mitocondriales/tratamiento farmacológico , Enfermedades Mitocondriales/metabolismo , Citrato de Sodio/administración & dosificación , Adenosina Trifosfato/metabolismo , Vías Biosintéticas , Estudios de Casos y Controles , Variaciones en el Número de Copia de ADN/efectos de los fármacos , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Femenino , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Hemo/biosíntesis , Hemo-Oxigenasa 1/genética , Hemo-Oxigenasa 1/metabolismo , Humanos , Técnicas In Vitro , Lactante , Recién Nacido , Masculino , Enfermedades Mitocondriales/genética , Fosforilación Oxidativa/efectos de los fármacos , Consumo de Oxígeno/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Regulación hacia Arriba/efectos de los fármacos
17.
Brain Dev ; 41(5): 465-469, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30739820

RESUMEN

Mutations in the mitochondrial tRNAMet gene have been reported in only five patients to date, all of whom presented with muscle weakness and exercise intolerance as signs of myopathy. We herein report the case of a 12-year-old girl with focal epilepsy since the age of eight years. At age 11, the patient developed sudden visual disturbances and headaches accompanied by recurrent, stroke-like episodes with lactic acidosis (pH 7.279, lactic acid 11.6 mmol/L). The patient frequently developed a delirious state, exhibited regression of intellectual ability. Brain magnetic resonance imaging revealed high-intensity signals on T2-weighted images of the left occipital lobe. Mitochondrial gene analysis revealed a heteroplasmic m.4450G > A mutation in the mitochondrial tRNAMet. The heteroplasmic rate of the m.4450G > A mutation in blood, skin, urinary sediment, hair, saliva, and nail samples were 20, 38, 59, 41, 27, and 35%, respectively. The patient's fibroblast showed an approximately 53% reduction in the oxygen consumption rate, compared to a control, and decreased complex I and IV activities. Stroke-like episodes, lactic acidosis, encephalopathy with brain magnetic resonance imaging findings, and declined mitochondrial function were consistent with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. To our knowledge, the findings associated with this first patient with MELAS syndrome harboring the m.4450G > A mutation in mitochondrial tRNAMet expand the phenotypic spectrum of tRNAMet gene.


Asunto(s)
Síndrome MELAS/diagnóstico , Síndrome MELAS/genética , Síndrome MELAS/fisiopatología , ARN Mitocondrial/genética , ARN de Transferencia de Metionina/genética , Niño , Femenino , Humanos
19.
Neurogenetics ; 20(1): 9-25, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30607703

RESUMEN

Pentatricopeptide repeat domain proteins are a large family of RNA-binding proteins involved in mitochondrial RNA editing, stability, and translation. Mitochondrial translation machinery defects are an expanding group of genetic diseases in humans. We describe a patient who presented with low birth weight, mental retardation, and optic atrophy. Brain MRI showed abnormal bilateral signals at the basal ganglia and brainstem, and the patient was diagnosed as Leigh syndrome. Exome sequencing revealed two potentially loss-of-function variants [c.415-2A>G, and c.1747_1748insCT (p.Phe583Serfs*3)] in PTCD3 (also known as MRPS39). PTCD3, a member of the pentatricopeptide repeat domain protein family, is a component of the small mitoribosomal subunit. The patient had marked decreases in mitochondrial complex I and IV levels and activities, oxygen consumption and ATP biosynthesis, and generalized mitochondrial translation defects in fibroblasts. Quantitative proteomic analysis revealed decreased levels of the small mitoribosomal subunits. Complementation experiments rescued oxidative phosphorylation complex I and IV levels and activities, ATP biosynthesis, and MT-RNR1 rRNA transcript level, providing functional validation of the pathogenicity of identified variants. This is the first report of an association of PTCD3 mutations with Leigh syndrome along with combined oxidative phosphorylation deficiencies caused by defects in the mitochondrial translation machinery.


Asunto(s)
Proteínas de Arabidopsis/genética , Enfermedad de Leigh/genética , Mutación/genética , Fosforilación Oxidativa , Proteínas de Unión al ARN/genética , Femenino , Humanos , Mitocondrias/genética , Linaje
20.
Genet Med ; 21(2): 512-515, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30190610

RESUMEN

In the above article, we noticed that one female patient in the positive group (plasma lyso-Gb3 7.6 ng/ml, α-galactosidase A activity 4.9 nmol/h/ml) who presented at the neurology clinic was already diagnosed with Fabry disease before the current study. We excluded patients with a confirmed diagnosis of Fabry disease and those with relatives known to have Fabry disease. To accurately describe the information in the current study, we must exclude this patient from the analysis. We have accurately revised this information as follows.

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