RESUMO
Primary mitochondrial complex I deficiency is the most common defect of the mitochondrial respiratory chain. It is caused by defects in structural components and assembly factors of this large protein complex. Mutations in the assembly factor NDUFAF5 are rare, with only five families reported to date. This study provides clinical, biochemical, molecular and functional data for four unrelated additional families, and three novel pathogenic variants. Three cases presented in infancy with lactic acidosis and classic Leigh syndrome. One patient, however, has a milder phenotype, with symptoms starting at 27â¯months and a protracted clinical course with improvement and relapsing episodes. She is homozygous for a previously reported mutation, p.Met279Arg and alive at 19â¯years with mild neurological involvement, normal lactate but abnormal urine organic acids. We found the same mutation in one of our severely affected patients in compound heterozygosity with a novel p.Lys52Thr mutation. Both patients with p.Met279Arg are of Taiwanese descent and had severe hyponatremia. Our third and fourth patients, both Caucasian, shared a common, newly described, missense mutation p.Lys109Asn which we show induces skipping of exon 3. Both Caucasian patients were compound heterozygotes, one with a previously reported Ashkenazi founder mutation while the other was negative for additional exonic variants. Whole genome sequencing followed by RNA studies revealed a novel deep intronic variant at position c.223-907A>C inducing an exonic splice enhancer. Our report adds significant new information to the mutational spectrum of NDUFAF5, further delineating the phenotypic heterogeneity of this mitochondrial defect.
Assuntos
Complexo I de Transporte de Elétrons/deficiência , Doença de Leigh/genética , Metiltransferases/genética , Doenças Mitocondriais/genética , Proteínas Mitocondriais/genética , Mutação , Fenótipo , Adolescente , Biópsia , Criança , Pré-Escolar , Complexo I de Transporte de Elétrons/genética , Feminino , Humanos , Lactente , Masculino , Linhagem , Pele/patologia , Sequenciamento do Exoma , Sequenciamento Completo do Genoma , Adulto JovemRESUMO
Inborn errors of vitamin B(12) (cobalamin) metabolism are characterized by decreased production of active cobalamin cofactors and subsequent deficiencies in the activities of methionine synthase and methylmalonyl-CoA mutase. With the recent discovery of the cblJ defect in two patients with phenotypes mimicking the cblF defect, there are nine genes known to be involved in cobalamin metabolism. The new defect is caused by mutations in the ABCD4 gene, encoding an ABC transporter. At the moment, there is no clear distinction between the cblJ and cblF defects either clinically or biochemically, and both defects result in blocks in the transport of cobalamin from the lysosome to the cytoplasm. A patient was diagnosed with hyperhomocysteinemia and methylmalonic aciduria at the age of 8 years. Incorporations of both [(14)C]propionate and [(14)C]methyltetrahydrofolate in cultured fibroblasts were within reference ranges and thus too high to allow for complementation analysis. We observed decreased synthesis of both adenosylcobalamin and methylcobalamin and accumulation of unmetabolized cyanocobalamin. Exome sequencing was performed to identify causative mutation(s) and Sanger re-sequencing was performed to validate segregation of mutation in the family. By this approach, a homozygous mutation, c.423C>G, in the ABCD4 gene was identified. Here, we report the successful application of exome sequencing for diagnosis of a rare inborn error of vitamin B(12) metabolism in a patient whose unusual presentation precluded diagnosis using standard biochemical and genetic approaches. The patient represents only the third known patient with the cblJ disorder.
Assuntos
Exoma , Erros Inatos do Metabolismo/diagnóstico , Erros Inatos do Metabolismo/genética , Mutação , Vitamina B 12/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Adolescente , Idade de Início , Alelos , Sequência de Bases , Fibroblastos/metabolismo , Genótipo , Humanos , Masculino , Erros Inatos do Metabolismo/terapia , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Linhagem , Vitamina B 12/sangueRESUMO
This commentary provides an overview of the putamen as an established target site for gene therapy in treating aromatic l-amino acid decarboxylase (AADC) deficiency and Parkinson's disease, two debilitating neurological disorders that involve motor dysfunction caused by dopamine deficiencies. The neuroanatomy and the function of the putamen in motor control provide good rationales for targeting this brain structure. Additionally, the efficacy and safety of intraputaminal gene therapy demonstrate that restoration of dopamine synthesis in the putamen by using low doses of adeno-associated viral vector serotype 2 to deliver the hAADC gene is well tolerated. This restoration leads to sustained improvements in motor and nonmotor symptoms of AADC deficiency and improved uptake and conversion of exogenous l-DOPA into dopamine in Parkinson's patients.
Assuntos
Carboxiliases , Doença de Parkinson , Descarboxilases de Aminoácido-L-Aromático/genética , Descarboxilases de Aminoácido-L-Aromático/metabolismo , Terapia Genética , Humanos , Doença de Parkinson/genética , Doença de Parkinson/terapia , Putamen/metabolismoRESUMO
BACKGROUND: Pompe disease is one of the few neuromuscular diseases with an approved drug therapy, which has been available since 2006. Our study aimed to determine the real-world long-term efficacy and safety of alglucosidase alfa. METHODS: This multicenter retrospective study (NCT02824068) collected data from adult Pompe disease patients receiving ERT for at least 3 years. Demographics and baseline characteristics, muscle strength, lung function (FVC), walking capability (6MWT), and safety were assessed once a year. Evaluation was done on the group and individual levels, using quantitative linear models (t test) and general univariate linear models (ANOVA). FINDINGS: Sixty-eight adult Pompe disease patients from four countries (Spain, Taiwan, Italy, Germany (STIG)) participated. The mean follow-up was 7.03 years ± 2.98. At group level in all outcome measures, an initial improvement followed by a secondary decline was observed. After 10 years, the 6MWT%pred showed the most sustained positive effect (p = 0.304). The MRC%max remained stable with a mild decline (p = 0.131), however, FVC%pred deteriorated significantly (p < 0.001) by 14.93% over 10 years of ERT. The progression rate of FVC%pred under ERT could be explained in most of the patients (83.5%) by the disease severity at baseline. Furthermore, our study shows a decline in the FVC combined with an increase in non-invasive and invasive ventilation requirements in adult Pompe disease patients over time. CONCLUSIONS: The STIG real-world study confirms an initial efficacy of ERT in the first years with a secondary sustained decline in multiple outcome measures. Further efforts are required to establish a more valid long-term monitoring and improved therapies.