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PURPOSE: Providing additional insights on the efficacy of human nuclear transfer (NT). Here, and earlier, NT has been applied to minimize transmission risk of mitochondrial DNA (mtDNA) diseases. NT has also been proposed for treating infertility, but it is still unclear which infertility indications would benefit. In this work, we therefore additionally assess the applicability of NT to overcome failed fertilization. METHODS: Patient 1 carries a homoplasmic mtDNA mutation (m.11778G > A). Seventeen metaphase II (MII) oocytes underwent pre-implantation genetic testing (PGT), while five MII oocytes were used for spindle transfer (ST), and one in vitro matured (IVM) metaphase I oocyte underwent early pronuclear transfer (ePNT). Patients 2-3 experienced multiple failed intracytoplasmic sperm injection (ICSI) and ICSI-assisted oocyte activation (AOA) cycles. For these patients, the obtained MII oocytes underwent an additional ICSI-AOA cycle, while the IVM oocytes were subjected to ST. RESULTS: For patient 1, PGT-M confirmed mutation loads close to 100%. All ST-reconstructed oocytes fertilized and cleaved, of which one progressed to the blastocyst stage. The reconstructed ePNT-zygote reached the morula stage. These samples showed an average mtDNA carry-over rate of 2.9% ± 0.8%, confirming the feasibility of NT to reduce mtDNA transmission. For patient 2-3 displaying fertilization failure, ST resulted in, respectively, 4/5 and 6/6 fertilized oocytes, providing evidence, for the first time, that NT can enable successful fertilization in this patient population. CONCLUSION: Our study showcases the repertoire of disorders for which NT can be beneficial, to overcome either mitochondrial disease transmission or failed fertilization after ICSI-AOA.
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Infertilidade , Doenças Mitocondriais , DNA Mitocondrial/genética , Fertilização , Fertilização in vitro/métodos , Humanos , Infertilidade/genética , Infertilidade/terapia , Oócitos , Injeções de Esperma IntracitoplásmicasRESUMO
Complex I deficiency is the most common biochemical phenotype observed in individuals with mitochondrial disease. With 44 structural subunits and over 10 assembly factors, it is unsurprising that complex I deficiency is associated with clinical and genetic heterogeneity. Massively parallel sequencing (MPS) technologies including custom, targeted gene panels or unbiased whole-exome sequencing (WES) are hugely powerful in identifying the underlying genetic defect in a clinical diagnostic setting, yet many individuals remain without a genetic diagnosis. These individuals might harbor mutations in poorly understood or uncharacterized genes, and their diagnosis relies upon characterization of these orphan genes. Complexome profiling recently identified TMEM126B as a component of the mitochondrial complex I assembly complex alongside proteins ACAD9, ECSIT, NDUFAF1, and TIMMDC1. Here, we describe the clinical, biochemical, and molecular findings in six cases of mitochondrial disease from four unrelated families affected by biallelic (c.635G>T [p.Gly212Val] and/or c.401delA [p.Asn134Ilefs(∗)2]) TMEM126B variants. We provide functional evidence to support the pathogenicity of these TMEM126B variants, including evidence of founder effects for both variants, and establish defects within this gene as a cause of complex I deficiency in association with either pure myopathy in adulthood or, in one individual, a severe multisystem presentation (chronic renal failure and cardiomyopathy) in infancy. Functional experimentation including viral rescue and complexome profiling of subject cell lines has confirmed TMEM126B as the tenth complex I assembly factor associated with human disease and validates the importance of both genome-wide sequencing and proteomic approaches in characterizing disease-associated genes whose physiological roles have been previously undetermined.
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Alelos , Complexo I de Transporte de Elétrons/deficiência , Proteínas de Membrana/genética , Doenças Mitocondriais/genética , Mutação/genética , Fenótipo , Adolescente , Adulto , Idade de Início , Sequência de Aminoácidos , Criança , Complexo I de Transporte de Elétrons/genética , Feminino , Humanos , Lactente , Masculino , Proteínas de Membrana/química , Pessoa de Meia-Idade , Linhagem , Adulto JovemRESUMO
Exome sequencing has recently identified mutations in the gene TANGO2 (transport and Golgi organization 2) as a cause of developmental delay associated with recurrent crises involving rhabdomyolysis, cardiac arrhythmias, and metabolic derangements. The disease is not well understood, in part as the cellular function and subcellular localization of the TANGO2 protein remain unknown. Furthermore, the clinical syndrome with its heterogeneity of symptoms, signs, and laboratory findings is still being defined. Here, we describe 11 new cases of TANGO2-related disease, confirming and further expanding the previously described clinical phenotype. Patients were homozygous or compound heterozygous for previously described exonic deletions or new frameshift, splice site, and missense mutations. All patients showed developmental delay with ataxia, dysarthria, intellectual disability, or signs of spastic diplegia. Of importance, we identify two subjects (aged 12 and 17 years) who have never experienced any overt episode of the catabolism-induced metabolic crises typical for the disease. Mitochondrial complex II activity was mildly reduced in patients investigated in association with crises but normal in other patients. In one deceased patient, post-mortem autopsy revealed heterotopic neurons in the cerebral white matter, indicating a possible role for TANGO2 in neuronal migration. Furthermore, we have addressed the subcellular localization of several alternative isoforms of TANGO2, none of which were mitochondrial but instead appeared to have a primarily cytoplasmic localization. Previously described aberrations in Golgi morphology were not observed in cultured skin fibroblasts.
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Translocador Nuclear Receptor Aril Hidrocarboneto/deficiência , Translocador Nuclear Receptor Aril Hidrocarboneto/genética , Deficiências do Desenvolvimento/genética , Metabolismo Energético/genética , Deficiência Intelectual/genética , Mitocôndrias/genética , Adolescente , Translocador Nuclear Receptor Aril Hidrocarboneto/fisiologia , Ataxia/genética , Paralisia Cerebral/genética , Criança , Pré-Escolar , Disartria/genética , Exoma , Éxons , Feminino , Humanos , Masculino , Mutação , Linhagem , Fenótipo , Sequenciamento do ExomaRESUMO
BACKGROUND: Mitochondrial disease is often suspected in cases of severe epileptic encephalopathy especially when a complex movement disorder, liver involvement and progressive developmental regression are present. Although mutations in either mitochondrial DNA or POLG are often present, other nuclear defects in mitochondrial DNA replication and protein translation have been associated with a severe epileptic encephalopathy. METHODS AND RESULTS: We identified a proband with an epileptic encephalopathy, complex movement disorder and a combined mitochondrial respiratory chain enzyme deficiency. The child presented with neurological regression, complex movement disorder and intractable seizures. A combined deficiency of mitochondrial complexes I, III and IV was noted in liver tissue, along with increased mitochondrial DNA content in skeletal muscle. Incomplete assembly of complex V, using blue native polyacrylamide gel electrophoretic analysis and complex I, using western blotting, suggested a disorder of mitochondrial transcription or translation. Exome sequencing identified compound heterozygous mutations in CARS2, a mitochondrial aminoacyl-tRNA synthetase. Both mutations affect highly conserved amino acids located within the functional ligase domain of the cysteinyl-tRNA synthase. A specific decrease in the amount of charged mt-tRNA(Cys) was detected in patient fibroblasts compared with controls. Retroviral transfection of the wild-type CARS2 into patient skin fibroblasts led to the correction of the incomplete assembly of complex V, providing functional evidence for the role of CARS2 mutations in disease aetiology. CONCLUSIONS: Our findings indicate that mutations in CARS2 result in a mitochondrial translational defect as seen in individuals with mitochondrial epileptic encephalopathy.
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Aminoacil-tRNA Sintetases/genética , Encefalopatias/genética , Epilepsia/genética , Sequência de Aminoácidos , Aminoacilação , Criança , Análise Mutacional de DNA , Exoma , Humanos , Masculino , Dados de Sequência Molecular , RNA de Transferência/metabolismo , Alinhamento de SequênciaRESUMO
A homozygous missense mutation (c.822G>C) was found in the gene encoding the mitochondrial asparaginyl-tRNA synthetase (NARS2) in two siblings born to consanguineous parents. These siblings presented with different phenotypes: one had mild intellectual disability and epilepsy in childhood, whereas the other had severe myopathy. Biochemical analysis of the oxidative phosphorylation (OXPHOS) complexes in both siblings revealed a combined complex I and IV deficiency in skeletal muscle. In-gel activity staining after blue native-polyacrylamide gel electrophoresis confirmed the decreased activity of complex I and IV, and, in addition, showed the presence of complex V subcomplexes. Considering the consanguineous descent, homozygosity mapping and whole-exome sequencing were combined revealing the presence of one single missense mutation in the shared homozygous region. The c.822G>C variant affects the 3' splice site of exon 7, leading to skipping of the whole exon 7 and a part of exon 8 in the NARS2 mRNA. In EBV-transformed lymphoblasts, a specific decrease in the amount of charged mt-tRNA(Asn) was demonstrated as compared with controls. This confirmed the pathogenic nature of the variant. To conclude, the reported variant in NARS2 results in a combined OXPHOS complex deficiency involving complex I and IV, making NARS2 a new member of disease-associated aaRS2.
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Aspartato-tRNA Ligase/genética , Mutação de Sentido Incorreto , Adulto , Aspartato-tRNA Ligase/metabolismo , Sequência de Bases , Células Cultivadas , Consanguinidade , Análise Mutacional de DNA , Feminino , Estudos de Associação Genética , Homozigoto , Humanos , Masculino , Doenças Musculares/genética , Biossíntese de Proteínas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Sítios de Splice de RNARESUMO
VPS45 mutations cause severe congenital neutropenia (SCN). We report on a girl with SCN and neurological impairment harboring a homozygous p.E238K mutation in VPS45 (vacuolar sorting protein 45). She successfully underwent hematopoietic stem cell transplantation. Our findings delineate the phenotype and indicate a possible genotype-phenotype correlation for neurological involvement.
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Homozigoto , Mutação/genética , Doenças do Sistema Nervoso/etiologia , Neutropenia/congênito , Proteínas de Transporte Vesicular/genética , Pré-Escolar , Síndrome Congênita de Insuficiência da Medula Óssea , Feminino , Genótipo , Humanos , Doenças do Sistema Nervoso/patologia , Neutropenia/complicações , Neutropenia/genética , Neutropenia/patologia , Fenótipo , PrognósticoRESUMO
Leukodystrophies are a heterogeneous group of severe genetic neurodegenerative disorders. A multiple mitochondrial dysfunctions syndrome was found in an infant presenting with a progressive leukoencephalopathy. Homozygosity mapping, whole exome sequencing, and functional studies were used to define the underlying molecular defect. Respiratory chain studies in skeletal muscle isolated from the proband revealed a combined deficiency of complexes I and II. In addition, western blotting indicated lack of protein lipoylation. The combination of these findings was suggestive for a defect in the iron-sulfur (Fe/S) protein assembly pathway. SNP array identified loss of heterozygosity in large chromosomal regions, covering the NFU1 and BOLA3, and the IBA57 and ABCB10 candidate genes, in 2p15-p11.2 and 1q31.1-q42.13, respectively. A homozygous c.436C > T (p.Arg146Trp) variant was detected in IBA57 using whole exome sequencing. Complementation studies in a HeLa cell line depleted for IBA57 showed that the mutant protein with the semi-conservative amino acid exchange was unable to restore the biochemical phenotype indicating a loss-of-function mutation of IBA57. In conclusion, defects in the Fe/S protein assembly gene IBA57 can cause autosomal recessive neurodegeneration associated with progressive leukodystrophy and fatal outcome at young age. In the affected patient, the biochemical phenotype was characterized by a defect in the respiratory chain complexes I and II and a decrease in mitochondrial protein lipoylation, both resulting from impaired assembly of Fe/S clusters.
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Proteínas de Transporte/genética , Proteínas Ferro-Enxofre/genética , Leucoencefalopatias/diagnóstico , Leucoencefalopatias/genética , Doenças Mitocondriais/diagnóstico , Complexo I de Transporte de Elétrons/genética , Evolução Fatal , Heterozigoto , Homozigoto , Humanos , Lactente , Imageamento por Ressonância Magnética , Masculino , Mitocôndrias/genética , Mutação , FenótipoAssuntos
Linfócitos B/metabolismo , Diferenciação Celular/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Haploinsuficiência , Fator de Transcrição Ikaros/genética , Adolescente , Doenças Assintomáticas , Linfócitos B/imunologia , Biomarcadores , Criança , Análise Mutacional de DNA , Feminino , Estudos de Associação Genética/métodos , Humanos , Imunofenotipagem , Masculino , Mutação , Linhagem , Sequenciamento do ExomaRESUMO
Schistosome worms inhabit mammalian mesenteric veins. Their eggs cause chronic inflammation, which progresses to periportal fibrosis in 5 to 30% of cases, increasing portal blood pressure and leading to esophageal varices. Episodes of bleeding cause hepatic necrosis and may ultimately lead to hepatic failure and the death of the patient. Schistosome infections can also cause pulmonary hypertension and heart failure. The mechanisms of fibrogenesis and fibrolysis are beginning to be unraveled, but it remains unclear why disease occurs only in certain subjects, as also observed for other types of chronic liver inflammation, as in hepatitis C or B. We summarize here the results that showed that fibrosis progression is determined by a genetic locus on chromosome 6. The CCN2 gene at this locus, encodes CTGF that is a crucial regulator of fibrosis. Two groups of CCN2 polymorphisms independently modulate the progression of hepatic fibrosis. These results were obtained in an Asian population, but were extended to humans living in Africa and South America and are presently tested in liver fibrosis of other etiological origins.
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Fator de Crescimento do Tecido Conjuntivo/fisiologia , Predisposição Genética para Doença , Cirrose Hepática/genética , Hepatopatias Parasitárias/genética , Esquistossomose/genética , Esplenopatias/genética , Animais , Povo Asiático/genética , Fator de Crescimento do Tecido Conjuntivo/genética , Progressão da Doença , Estudos de Associação Genética , Humanos , Cirrose Hepática/etnologia , Cirrose Hepática/etiologia , Cirrose Hepática/parasitologia , Hepatopatias Parasitárias/etnologia , Hepatopatias Parasitárias/etiologia , Schistosoma/fisiologia , Esquistossomose/complicações , Esquistossomose/etnologia , Índice de Gravidade de Doença , Esplenopatias/etnologia , Esplenopatias/etiologia , Esplenopatias/parasitologiaRESUMO
The environmental quality of the Jacuípe River's estuary (very important in northeastern Brazil) was assessed during 2007 and 2008. In water, concentrations (mg L⻹) of NO2â» (<0.004 to 0.016), NO3â» (0.01 to 0.33), soluble PO4³â» (<0.02 to 0.22), dissolved oxygen (3.9 to 9.6), total contents (mg L⻹) of Cd (<0.001), Cu (<0.01), Pb (<0.01), and Zn (<0.1), pH (5.60 to 8.00), and electrical conductivity (0.12 to 48.60 mS cm⻹) agreed with environmental standards. In sediments, clay and total organic matter (%, m/m) varied, respectively, from 8.8 to 12.0 and from 1.1 to 8.8, while infrared, thermogravimetric profile, electronic micrograph, as well as X-Ray analyses showed desirable adsorptive characteristics. However, maximum exchangeable levels (mg kg⻹) of Cd (1.3), Cu (44.6), Pb (35.7), and Zn (43.7) and their respective maximum pseudototal concentrations (mg kg⻹): 19.4, 95.1, 68.2, and 30.3 were below the recommended limits. In this sense, it was possible to demonstrate good environmental preservation even with the growing number of industries and touristic activities in the evaluated estuarine area.
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Sedimentos Geológicos/química , Clima Tropical , Água/química , Brasil , Microscopia Eletrônica , Espectrofotometria Atômica , TermogravimetriaRESUMO
BACKGROUND: In order to facilitate the diagnostic process for adult patients suffering from a rare disease, the Undiagnosed Disease Program (UD-PrOZA) was founded in 2015 at the Ghent University Hospital in Belgium. In this study we report the five-year results of our multidisciplinary approach in rare disease diagnostics. METHODS: Patients referred by a healthcare provider, in which an underlying rare disease is likely, qualify for a UD-PrOZA evaluation. UD-PrOZA uses a multidisciplinary clinical approach combined with state-of-the-art genomic technologies in close collaboration with research facilities to diagnose patients. RESULTS: Between 2015 and 2020, 692 patients (94% adults) were referred of which 329 (48%) were accepted for evaluation. In 18% (60 of 329) of the cases a definite diagnosis was made. 88% (53 of 60) of the established diagnoses had a genetic origin. 65% (39 of 60) of the genetic diagnoses were made through whole exome sequencing (WES). The mean time interval between symptom-onset and diagnosis was 19 years. Key observations included novel genotype-phenotype correlations, new variants in known disease genes and the identification of three new disease genes. In 13% (7 of 53), identifying the molecular cause was associated with therapeutic recommendations and in 88% (53 of 60), gene specific genetic counseling was made possible. Actionable secondary findings were reported in 7% (12 of 177) of the patients in which WES was performed. CONCLUSION: UD-PrOZA offers an innovative interdisciplinary platform to diagnose rare diseases in adults with previously unexplained medical problems and to facilitate translational research.
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Doenças Raras , Doenças não Diagnosticadas , Exoma , Genômica , Humanos , Doenças Raras/diagnóstico , Doenças Raras/genética , Sequenciamento do ExomaRESUMO
Deficiency of the serine hydrolase prolyl endopeptidase-like (PREPL) causes a recessive metabolic disorder characterized by neonatal hypotonia, feeding difficulties, and growth hormone deficiency. The pathophysiology of PREPL deficiency and the physiological substrates of PREPL remain largely unknown. In this study, we connect PREPL with mitochondrial gene expression and oxidative phosphorylation by analyzing its protein interactors. We demonstrate that the long PREPLL isoform localizes to mitochondria, whereas PREPLS remains cytosolic. Prepl KO mice showed reduced mitochondrial complex activities and disrupted mitochondrial gene expression. Furthermore, mitochondrial ultrastructure was abnormal in a PREPL-deficient patient and Prepl KO mice. In addition, we reveal that PREPL has (thio)esterase activity and inhibition of PREPL by Palmostatin M suggests a depalmitoylating function. We subsequently determined the crystal structure of PREPL, thereby providing insight into the mechanism of action. Taken together, PREPL is a (thio)esterase rather than a peptidase and PREPLL is involved in mitochondrial homeostasis.
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BACKGROUND: The first subjects with deficiency of mitochondrial tryptophanyl-tRNA synthetase (WARS2) were reported in 2017. Their clinical characteristics can be subdivided into three phenotypes (neonatal phenotype, severe infantile onset phenotype, Parkinson-like phenotype). RESULTS: Here, we report on a subject who presented with early developmental delay, motor weakness and intellectual disability and who was considered during several years as having a non-progressive encephalopathy. At the age of six years, she had an epileptic seizure which was treated with sodium valproate. In the months after treatment was started, she developed acute liver failure and severe progressive encephalopathy. Although valproate was discontinued, she died six months later. Spectrophotometric analysis of the oxidative phosphorylation complexes in liver revealed a deficient activity of complex III and low normal activities of the complexes I and IV. Activity staining in the BN-PAGE gel confirmed the low activities of complex I, III and IV and, in addition, showed the presence of a subcomplex of complex V. Histochemically, a mosaic pattern was seen in hepatocytes after cytochrome c oxidase staining. Using Whole Exome Sequencing two known pathogenic variants were detected in WARS2 (c.797delC, p.Pro266ArgfsTer10/ c.938 A > T, p.Lys313Met). CONCLUSION: This is the first report of severe hepatopathy in a subject with WARS2 deficiency. The hepatopathy occurred soon after start of sodium valproate treatment. In the literature, valproate-induced hepatotoxicity was reported in the subjects with pathogenic mutations in POLG and TWNK. This case report illustrates that the course of the disease in the subjects with a mitochondrial defect can be non-progressive during several years. The subject reported here was first diagnosed as having cerebral palsy. Only after a mitochondriotoxic medication was started, the disease became progressive, and the diagnosis of a mitochondrial defect was made.
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Mitocôndrias/metabolismo , Triptofano-tRNA Ligase/deficiência , Triptofano-tRNA Ligase/metabolismo , Ácido Valproico/uso terapêutico , Aminoacil-tRNA Sintetases/genética , Aminoacil-tRNA Sintetases/metabolismo , Western Blotting , Criança , DNA Polimerase gama/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Eletroforese em Gel de Poliacrilamida , Exoma/genética , Feminino , Humanos , Mitocôndrias/efeitos dos fármacos , Doenças Mitocondriais/tratamento farmacológico , Doenças Mitocondriais/metabolismo , Sequenciamento do ExomaRESUMO
OBJECTIVE: To report the clinical, radiologic, biochemical, and molecular characteristics in a 46-year-old participant with adult-onset Leigh syndrome (LS), followed by parkinsonism. METHODS: Case description with diagnostic workup included blood and CSF analysis, skeletal muscle investigations, blue native polyacrylamide gel electrophoresis, whole exome sequencing targeting nuclear genes involved in mitochondrial transcription and translation, cerebral MRI, 123I-FP-CIT brain single-photon emission computed tomography (SPECT), and C-11 raclopride positron emission tomography (PET). RESULTS: The participant was found to have a defect in the oxidative phosphorylation caused by a c.626C>T mutation in the gene coding for mitochondrial methionyl-tRNA formyltransferase (MTFMT), which is a pathogenic mutation affecting intramitochondrial protein translation. The proband had a normal concentration of lactate in blood and no abnormal microscopic findings in skeletal muscle. Cerebral MRI showed bilateral lesions in the striatum, mesencephalon, pons, and medial thalamus. Lactate concentration in CSF was increased. FP-CIT SPECT and C-11 raclopride PET demonstrated a defect in the dopaminergic system. CONCLUSIONS: We report on a case with adult-onset LS related to a MTFMT mutation. Two years after the onset of symptoms of LS, the proband developed a parkinson-like disease. The c.626C>T mutation is the most common pathogenic mutation found in 22 patients reported earlier in the literature with a defect in MTFMT. The age of the previously reported cases varied between 14 months and 24 years. Our report expands the phenotypical spectrum of MTFMT-related neurologic disease and provides clinical evidence for involvement of MTFMT in extrapyramidal syndromes.
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Megaconial congenital muscular dystrophy is a disease caused by pathogenic mutations in the gene encoding choline kinase beta (CHKB). Microscopically, the disease is hallmarked by the presence of enlarged mitochondria at the periphery of skeletal muscle fibres leaving the centre devoid of mitochondria. Clinical characteristics are delayed motor development, intellectual disability and dilated cardiomyopathy in half of reported cases. This study describes a patient presenting with the cardinal clinical features, in whom a homozygous nonsense mutation (c.248_249insT; p.Arg84Profs*209) was identified in CHKB and who was treated by heart transplantation. Microscopic evaluation of skeletal and heart muscles typically showed enlarged mitochondria. Spectrophotometric evaluation in both tissues revealed a mild decrease of all OXPHOS complexes. Using BN-PAGE analysis followed by activity staining subcomplexes of complex V were detected in both tissues, indicating incomplete complex V assembly. Mitochondrial DNA content was not depleted in analysed tissues. This is the first report describing the microscopic and biochemical abnormalities in the heart from an affected patient. A likely hypothesis is that the biochemical findings are caused by an abnormal lipid profile in the inner mitochondrial membrane resulting from a defective choline kinase B activity.
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Colina Quinase/genética , Códon sem Sentido , Membranas Mitocondriais/fisiologia , Miopatias Mitocondriais/patologia , Distrofias Musculares/patologia , Miocárdio/patologia , Adenosina Trifosfatases/análise , Proteínas de Transporte/análise , Criança , Transplante de Coração , Humanos , Masculino , Proteínas de Membrana/análise , Microscopia , Mitocôndrias/patologia , Miopatias Mitocondriais/diagnóstico , Miopatias Mitocondriais/genética , Miopatias Mitocondriais/terapia , ATPases Mitocondriais Próton-Translocadoras , Distrofias Musculares/diagnóstico , Distrofias Musculares/genética , Distrofias Musculares/terapia , Fosforilação OxidativaRESUMO
The purpose of this paper is to test whether peripheral oxygenation responses measured with near-infrared spectroscopy (NIRS) would differ between patients suffering from mitochondrial myopathy (MM) and healthy controls during an incremental handgrip exercise test. Two groups of subjects were studied: 11 patients with MM and 11 age- and gender-matched untrained healthy controls. A handgrip exercise until exhaustion protocol was used consisting of 2 min periods of work (½ Hz) at different intensities, separated by a 60 s rest period. The changes in deoxyhemoglobin and deoxymyoglobin (deoxy[Hb + Mb]) during each work step were expressed in percent to the maximum deoxy[Hb + Mb]-value measured during arterial occlusion in forearm muscles. A repeated measures analysis of variance was used to compare the increase in deoxy[Hb + Mb] between MM patients and controls with increasing intensity. Statistical analysis revealed a significant difference between both populations (P < 0.001) indicating that the increase in deoxy[Hb + Mb] showed a significantly different pattern in the two populations. In the post hoc analysis significant lower deoxy[Hb + Mb] -values were found for MM patients at every intensity. The results of this paper show significantly different skeletal muscle oxygenation responses, measured with an optical method as NIRS, between MM patients and age- and gender-matched healthy subjects at submaximal and maximal level during an incremental handgrip exercise. This optical method is thus a valuable tool to assess differences in peripheral oxygenation. Moreover, this method could be used as an evaluation tool for follow up in interventional pharmacological studies and rehabilitation programs.
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Força da Mão , Hemoglobinas/metabolismo , Miopatias Mitocondriais/metabolismo , Músculo Esquelético/fisiopatologia , Mioglobina/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Adulto , Feminino , Antebraço , Humanos , Masculino , Miopatias Mitocondriais/diagnóstico , Oximetria/métodos , Oxigênio/metabolismo , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Disorders of the mitochondrial energy metabolism are clinically and genetically heterogeneous. An increasingly recognized subgroup is caused by defective mitochondrial iron-sulfur (Fe-S) cluster biosynthesis, with defects in 13 genes being linked to human disease to date. Mutations in three of them, NFU1, BOLA3, and IBA57, affect the assembly of mitochondrial [4Fe-4S] proteins leading to an impairment of diverse mitochondrial metabolic pathways and ATP production. Patients with defects in these three genes present with lactic acidosis, hyperglycinemia, and reduced activities of respiratory chain complexes I and II, the four lipoic acid-dependent 2-oxoacid dehydrogenases and the glycine cleavage system (GCS). To date, five different NFU1 pathogenic variants have been reported in 15 patients from 12 families. We report on seven new patients from five families carrying compound heterozygous or homozygous pathogenic NFU1 mutations identified by candidate gene screening and exome sequencing. Six out of eight different disease alleles were novel and functional studies were performed to support the pathogenicity of five of them. Characteristic clinical features included fatal infantile encephalopathy and pulmonary hypertension leading to death within the first 6 months of life in six out of seven patients. Laboratory investigations revealed combined defects of pyruvate dehydrogenase complex (five out of five) and respiratory chain complexes I and II+III (four out of five) in skeletal muscle and/or cultured skin fibroblasts as well as increased lactate (five out of six) and glycine concentration (seven out of seven). Our study contributes to a better definition of the phenotypic spectrum associated with NFU1 mutations and to the diagnostic workup of future patients.
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This communication describes a general method for templating fungal filaments with gold nanoparticles that results in a gold replica of filaments after calcination of the biological template.