RESUMEN
JAG2 encodes the Notch ligand Jagged2. The conserved Notch signaling pathway contributes to the development and homeostasis of multiple tissues, including skeletal muscle. We studied an international cohort of 23 individuals with genetically unsolved muscular dystrophy from 13 unrelated families. Whole-exome sequencing identified rare homozygous or compound heterozygous JAG2 variants in all 13 families. The identified bi-allelic variants include 10 missense variants that disrupt highly conserved amino acids, a nonsense variant, two frameshift variants, an in-frame deletion, and a microdeletion encompassing JAG2. Onset of muscle weakness occurred from infancy to young adulthood. Serum creatine kinase (CK) levels were normal or mildly elevated. Muscle histology was primarily dystrophic. MRI of the lower extremities revealed a distinct, slightly asymmetric pattern of muscle involvement with cores of preserved and affected muscles in quadriceps and tibialis anterior, in some cases resembling patterns seen in POGLUT1-associated muscular dystrophy. Transcriptome analysis of muscle tissue from two participants suggested misregulation of genes involved in myogenesis, including PAX7. In complementary studies, Jag2 downregulation in murine myoblasts led to downregulation of multiple components of the Notch pathway, including Megf10. Investigations in Drosophila suggested an interaction between Serrate and Drpr, the fly orthologs of JAG1/JAG2 and MEGF10, respectively. In silico analysis predicted that many Jagged2 missense variants are associated with structural changes and protein misfolding. In summary, we describe a muscular dystrophy associated with pathogenic variants in JAG2 and evidence suggests a disease mechanism related to Notch pathway dysfunction.
Asunto(s)
Proteína Jagged-2/genética , Distrofias Musculares/genética , Adolescente , Adulto , Secuencia de Aminoácidos , Animales , Línea Celular , Niño , Preescolar , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Femenino , Glucosiltransferasas/genética , Haplotipos/genética , Humanos , Proteína Jagged-1/genética , Proteína Jagged-2/química , Proteína Jagged-2/deficiencia , Proteína Jagged-2/metabolismo , Masculino , Proteínas de la Membrana/genética , Ratones , Persona de Mediana Edad , Modelos Moleculares , Músculos/metabolismo , Músculos/patología , Distrofias Musculares/patología , Mioblastos/metabolismo , Mioblastos/patología , Linaje , Fenotipo , Receptores Notch/metabolismo , Transducción de Señal , Secuenciación del Exoma , Adulto JovenRESUMEN
Distal hereditary motor neuropathies (HMNs) and axonal Charcot-Marie-Tooth neuropathy (CMT2) are clinically and genetically heterogeneous diseases characterized primarily by motor neuron degeneration and distal weakness. The genetic cause for about half of the individuals affected by HMN/CMT2 remains unknown. Here, we report the identification of pathogenic variants in GBF1 (Golgi brefeldin A-resistant guanine nucleotide exchange factor 1) in four unrelated families with individuals affected by sporadic or dominant HMN/CMT2. Genomic sequencing analyses in seven affected individuals uncovered four distinct heterozygous GBF1 variants, two of which occurred de novo. Other known HMN/CMT2-implicated genes were excluded. Affected individuals show HMN/CMT2 with slowly progressive distal muscle weakness and musculoskeletal deformities. Electrophysiological studies confirmed axonal damage with chronic neurogenic changes. Three individuals had additional distal sensory loss. GBF1 encodes a guanine-nucleotide exchange factor that facilitates the activation of members of the ARF (ADP-ribosylation factor) family of small GTPases. GBF1 is mainly involved in the formation of coatomer protein complex (COPI) vesicles, maintenance and function of the Golgi apparatus, and mitochondria migration and positioning. We demonstrate that GBF1 is present in mouse spinal cord and muscle tissues and is particularly abundant in neuropathologically relevant sites, such as the motor neuron and the growth cone. Consistent with the described role of GBF1 in Golgi function and maintenance, we observed marked increase in Golgi fragmentation in primary fibroblasts derived from all affected individuals in this study. Our results not only reinforce the existing link between Golgi fragmentation and neurodegeneration but also demonstrate that pathogenic variants in GBF1 are associated with HMN/CMT2.
Asunto(s)
Axones/metabolismo , Enfermedad de Charcot-Marie-Tooth/genética , Factores de Intercambio de Guanina Nucleótido/genética , Debilidad Muscular/genética , Atrofia Muscular Espinal/genética , Anomalías Musculoesqueléticas/genética , Adulto , Anciano , Anciano de 80 o más Años , Secuencia de Aminoácidos , Animales , Axones/patología , Vesículas Cubiertas por Proteínas de Revestimiento/metabolismo , Vesículas Cubiertas por Proteínas de Revestimiento/patología , Enfermedad de Charcot-Marie-Tooth/diagnóstico , Enfermedad de Charcot-Marie-Tooth/metabolismo , Enfermedad de Charcot-Marie-Tooth/patología , Femenino , Fibroblastos/metabolismo , Fibroblastos/patología , Expresión Génica , Aparato de Golgi/metabolismo , Aparato de Golgi/patología , Factores de Intercambio de Guanina Nucleótido/metabolismo , Heterocigoto , Humanos , Masculino , Ratones , Persona de Mediana Edad , Mitocondrias/metabolismo , Mitocondrias/patología , Neuronas Motoras/metabolismo , Neuronas Motoras/patología , Debilidad Muscular/diagnóstico , Debilidad Muscular/metabolismo , Debilidad Muscular/patología , Atrofia Muscular Espinal/diagnóstico , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular Espinal/patología , Anomalías Musculoesqueléticas/diagnóstico , Anomalías Musculoesqueléticas/metabolismo , Anomalías Musculoesqueléticas/patología , Mutación , Linaje , Cultivo Primario de Células , Médula Espinal/anomalías , Médula Espinal/metabolismoRESUMEN
Hereditary lower motor neuron diseases (LMND) other than 5q-spinal muscular atrophy (5q-SMA) can be classified according to affected muscle groups. Proximal and distal forms of non-5q-SMA represent a clinically and genetically heterogeneous spectrum characterized by significant overlaps with axonal forms of Charcot-Marie-Tooth (CMT) disease. A consensus for the best approach to molecular diagnosis needs to be reached, especially in light of continuous novel gene discovery and falling costs of next-generation sequencing (NGS). We performed exome sequencing (ES) in 41 families presenting with non-5q-SMA or axonal CMT, 25 of which had undergone a previous negative neuromuscular disease (NMD) gene panel analysis. The total diagnostic yield of ES was 41%. Diagnostic success in the cohort with a previous NMD-panel analysis was significantly extended by ES, primarily due to novel gene associated-phenotypes and uncharacteristic phenotypic presentations. We recommend early ES for individuals with hereditary LMND presenting uncharacteristic or significantly overlapping features. As mitochondrial dysfunction was the underlying pathomechanism in 47% of the solved individuals, we highlight the sensitivity of the anterior horn cell and peripheral nerve to mitochondrial imbalance as well as the necessity to screen for mitochondrial disorders in individuals presenting predominant lower motor neuron symptoms.
Asunto(s)
Enfermedad de Charcot-Marie-Tooth , Atrofia Muscular Espinal , Enfermedad de Charcot-Marie-Tooth/diagnóstico , Enfermedad de Charcot-Marie-Tooth/genética , Genómica , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Mitocondrias/genética , Atrofia Muscular Espinal/diagnóstico , Atrofia Muscular Espinal/genéticaRESUMEN
OBJECTIVE: Weight loss has been identified as a negative prognostic factor in amyotrophic lateral sclerosis, but there is no evidence regarding whether a high-caloric diet increases survival. Therefore, we sought to evaluate the efficacy of a high-caloric fatty diet (HCFD) for increasing survival. METHODS: A 1:1 randomized, placebo-controlled, parallel-group, double-blinded trial (LIPCAL-ALS study) was conducted between February 2015 and September 2018. Patients were followed up at 3, 6, 9, 12, 15, and 18 months after randomization. The study was performed at 12 sites of the clinical and scientific network of German motor neuron disease centers (ALS/MND-NET). Eligible patients were randomly assigned (1:1) to receive either HCFD (405kcal/day, 100% fat) or placebo in addition to riluzole (100mg/day). The primary endpoint was survival time, defined as time to death or time to study cutoff date. RESULTS: Two hundred one patients (80 female, 121 male, age = 62.4 ± 10.8 years) were included. The confirmatory analysis of the primary outcome survival showed a survival probability of 0.39 (95% confidence interval [CI] = 0.27-0.51) in the placebo group and 0.37 (95% CI = 0.25-0.49) in the HCFD group, both after 28 months (point in time of the last event). The hazard ratio was 0.97, 1-sided 97.5% CI = -∞ to 1.44, p = 0.44. INTERPRETATION: The results provide no evidence for a life-prolonging effect of HCFD for the whole amyotrophic lateral sclerosis population. However, post hoc analysis revealed a significant survival benefit for the subgroup of fast-progressing patients. ANN NEUROL 2020;87:206-216.
Asunto(s)
Esclerosis Amiotrófica Lateral/dietoterapia , Esclerosis Amiotrófica Lateral/mortalidad , Dieta Alta en Grasa/mortalidad , Esclerosis Amiotrófica Lateral/tratamiento farmacológico , Terapia Combinada/métodos , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fármacos Neuroprotectores/uso terapéutico , Riluzol/uso terapéutico , Análisis de SupervivenciaRESUMEN
BACKGROUND AND PURPOSE: Pathogenic variants in PLEKHG5 have been reported to date to be causative in three unrelated families with autosomal recessive intermediate Charcot-Marie-Tooth disease (CMT) and in one consanguineous family with spinal muscular atrophy (SMA). PLEKHG5 is known to be expressed in the human peripheral nervous system, and previous studies have shown its function in axon terminal autophagy of synaptic vesicles, lending support to its underlying pathogenetic mechanism. Despite this, there is limited knowledge of the clinical and genetic spectrum of disease. METHODS: We leverage the diagnostic utility of exome and genome sequencing and describe novel biallelic variants in PLEKHG5 in 13 individuals from nine unrelated families originating from four different countries. We compare our phenotypic and genotypic findings with a comprehensive review of cases previously described in the literature. RESULTS: We found that patients presented with variable disease severity at different ages of onset (8-25 years). In our cases, weakness usually started proximally, progressing distally, and can be associated with intermediate slow conduction velocities and minor clinical sensory involvement. We report three novel nonsense and four novel missense pathogenic variants associated with these PLEKHG5-associated neuropathies, which are phenotypically spinal muscular atrophy (SMA) or intermediate Charcot-Marie-Tooth disease. CONCLUSIONS: PLEKHG5-associated neuropathies should be considered as an important differential in non-5q SMAs even in the presence of mild sensory impairment and a candidate causative gene for a wide range of hereditary neuropathies. We present this series of cases to further the understanding of the phenotypic and molecular spectrum of PLEKHG5-associated diseases.
Asunto(s)
Enfermedad de Charcot-Marie-Tooth , Enfermedad de Charcot-Marie-Tooth/genética , Consanguinidad , Genes Recesivos , Genotipo , Factores de Intercambio de Guanina Nucleótido , Humanos , Mutación , FenotipoRESUMEN
Spinal muscular atrophies (SMAs) are a heterogeneous group of disorders characterized by muscular atrophy, weakness, and hypotonia due to suspected lower motor neuron degeneration (LMND). In a large cohort of 3,465 individuals suspected with SMA submitted for SMN1 testing to our routine diagnostic laboratory, 48.8% carried a homozygous SMN1 deletion, 2.8% a subtle mutation, and an SMN1 deletion, whereas 48.4% remained undiagnosed. Recently, several other genes implicated in SMA/LMND have been reported. Despite several efforts to establish a diagnostic algorithm for non-5q-SMA (SMA without deletion or point mutations in SMN1 [5q13.2]), data from large-scale studies are not available. We tested the clinical utility of targeted sequencing in non-5q-SMA by developing two different gene panels. We first analyzed 30 individuals with a small panel including 62 genes associated with LMND using IonTorrent-AmpliSeq target enrichment. Then, additional 65 individuals were tested with a broader panel encompassing up to 479 genes implicated in neuromuscular diseases (NMDs) with Agilent-SureSelect target enrichment. The NMD panel provided a higher diagnostic yield (33%) than the restricted LMND panel (13%). Nondiagnosed cases were further subjected to exome or genome sequencing. Our experience supports the use of gene panels covering a broad disease spectrum for diseases that are highly heterogeneous and clinically difficult to differentiate.
Asunto(s)
Atrofia Muscular Espinal/diagnóstico , Atrofia Muscular Espinal/genética , Enfermedades Neuromusculares/diagnóstico , Patología Molecular , Adolescente , Adulto , Edad de Inicio , Niño , Preescolar , Exones/genética , Femenino , Secuenciación de Nucleótidos de Alto Rendimiento , Homocigoto , Humanos , Lactante , Masculino , Persona de Mediana Edad , Atrofia Muscular Espinal/patología , Enfermedades Neuromusculares/genética , Enfermedades Neuromusculares/fisiopatología , Mutación Puntual , Eliminación de Secuencia , Proteína 1 para la Supervivencia de la Neurona Motora/genética , Secuenciación del Exoma , Secuenciación Completa del Genoma , Adulto JovenRESUMEN
Hereditary neuropathies comprise a wide variety of chronic diseases associated to more than 80 genes identified to date. We herein examined 612 index patients with either a Charcot-Marie-Tooth phenotype, hereditary sensory neuropathy, familial amyloid neuropathy, or small fiber neuropathy using a customized multigene panel based on the next generation sequencing technique. In 121 cases (19.8%), we identified at least one putative pathogenic mutation. Of these, 54.4% showed an autosomal dominant, 33.9% an autosomal recessive, and 11.6% an X-linked inheritance. The most frequently affected genes were PMP22 (16.4%), GJB1 (10.7%), MPZ, and SH3TC2 (both 9.9%), and MFN2 (8.3%). We further detected likely or known pathogenic variants in HINT1, HSPB1, NEFL, PRX, IGHMBP2, NDRG1, TTR, EGR2, FIG4, GDAP1, LMNA, LRSAM1, POLG, TRPV4, AARS, BIC2, DHTKD1, FGD4, HK1, INF2, KIF5A, PDK3, REEP1, SBF1, SBF2, SCN9A, and SPTLC2 with a declining frequency. Thirty-four novel variants were considered likely pathogenic not having previously been described in association with any disorder in the literature. In one patient, two homozygous mutations in HK1 were detected in the multigene panel, but not by whole exome sequencing. A novel missense mutation in KIF5A was considered pathogenic because of the highly compatible phenotype. In one patient, the plasma sphingolipid profile could functionally prove the pathogenicity of a mutation in SPTLC2. One pathogenic mutation in MPZ was identified after being previously missed by Sanger sequencing. We conclude that panel based next generation sequencing is a useful, time- and cost-effective approach to assist clinicians in identifying the correct diagnosis and enable causative treatment considerations.
Asunto(s)
Predisposición Genética a la Enfermedad , Neuropatía Hereditaria Motora y Sensorial/genética , Mutación/genética , Enfermedades Raras/genética , Enfermedad de Charcot-Marie-Tooth/genética , Femenino , Proteínas de Choque Térmico HSP27/genética , Proteínas de Choque Térmico , Neuropatía Hereditaria Motora y Sensorial/diagnóstico , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Masculino , Chaperonas Moleculares , FenotipoRESUMEN
BACKGROUND AND OBJECTIVES: Autoimmune nodopathies with antibodies against the paranodal proteins show a distinct phenotype of a severe sensorimotor neuropathy. In some patients, complete remission can be achieved after treatment with rituximab whereas others show a chronic course. For optimal planning of treatment, predicting the course of disease and therapeutic response is crucial. METHODS: We stimulated peripheral blood mononuclear cells in vitro to find out whether secretion of specific autoantibodies may be a predictor of the course of disease and response to rituximab. RESULTS: Three patterns could be identified: In most patients with anti-Neurofascin-155-, anti-Contactin-1-, and anti-Caspr1-IgG4 autoantibodies, in vitro production of autoantibodies was detected, indicating autoantigen-specific memory B cells and short-lived plasma cells/plasmablasts as the major source of autoantibodies. These patients generally showed a good response to rituximab. In a subgroup of patients with anti-Neurofascin-155-IgG4 autoantibodies and insufficient response to rituximab, no in vitro autoantibody production was found despite high serum titers, indicating autoantibody secretion by long-lived plasma cells outside the peripheral blood. In the patients with anti-pan-Neurofascin autoantibodies-all with a monophasic course of disease-no in vitro autoantibody production could be measured, suggesting a lack of autoantigen-specific memory B cells. In some of them, autoantibody production by unstimulated cells was detectable, presumably corresponding to high amounts of autoantigen-specific plasmablasts-well in line with a severe but monophasic course of disease. DISCUSSION: Our data suggest that different B-cell responses may occur in autoimmune nodopathies and may serve as markers of courses of disease and response to rituximab.
Asunto(s)
Autoanticuerpos , Leucocitos Mononucleares , Rituximab , Humanos , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , Femenino , Masculino , Adulto , Leucocitos Mononucleares/inmunología , Rituximab/farmacología , Persona de Mediana Edad , Factores de Crecimiento Nervioso/inmunología , Adulto Joven , Contactina 1/inmunología , Anciano , Enfermedades Autoinmunes del Sistema Nervioso/inmunología , Enfermedades Autoinmunes del Sistema Nervioso/tratamiento farmacológico , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Adolescente , Moléculas de Adhesión Celular/inmunologíaRESUMEN
Background: Evidence for the efficacy of nusinersen in adults with 5q-associated spinal muscular atrophy (SMA) has been demonstrated up to a period of 16 months in relatively large cohorts but whereas patients reach a plateau over time is still to be demonstrated. We investigated the efficacy and safety of nusinersen in adults with SMA over 38 months, the longest time period to date in a large cohort of patients from multiple clinical sites. Methods: Our prospective, observational study included adult patients with SMA from Germany, Switzerland, and Austria (July 2017 to May 2022). All participants had genetically-confirmed, 5q-associated SMA and were treated with nusinersen according to the label. The total Hammersmith Functional Motor Scale Expanded (HFMSE) and Revised Upper Limb Module (RULM) scores, and 6-min walk test (6 MWT; metres), were recorded at baseline and 14, 26, and 38 months after treatment initiation, and pre and post values were compared. Adverse events were also recorded. Findings: Overall, 389 patients were screened for eligibility and 237 were included. There were significant increases in all outcome measures compared with baseline, including mean HFMSE scores at 14 months (mean difference 1.72 [95% CI 1.19-2.25]), 26 months (1.20 [95% CI 0.48-1.91]), and 38 months (1.52 [95% CI 0.74-2.30]); mean RULM scores at 14 months (mean difference 0.75 [95% CI 0.43-1.07]), 26 months (mean difference 0.65 [95% CI 0.27-1.03]), and 38 months (mean difference 0.72 [95% CI 0.25-1.18]), and 6 MWT at 14 months (mean difference 30.86 m [95% CI 18.34-43.38]), 26 months (mean difference 29.26 m [95% CI 14.87-43.65]), and 38 months (mean difference 32.20 m [95% CI 10.32-54.09]). No new safety signals were identified. Interpretation: Our prospective, observational, long-term (38 months) data provides further real-world evidence for the continuous efficacy and safety of nusinersen in a large proportion of adult patients with SMA. Funding: Financial support for the registry from Biogen, Novartis and Roche.
RESUMEN
Newborn screening for 5qSMA offers the potential for early, ideally pre-symptomatic, therapeutic intervention. However, limited data exist on the outcomes of individuals with 4 copies of SMN2, and there is no consensus within the SMA treatment community regarding early treatment initiation in this subgroup. To provide evidence-based insights into disease progression, we performed a retrospective analysis of 268 patients with 4 copies of SMN2 from the SMArtCARE registry in Germany, Austria and Switzerland. Inclusion criteria required comprehensive baseline data and diagnosis outside of newborn screening. Only data prior to initiation of disease-modifying treatment were included. The median age at disease onset was 3.0 years, with a mean of 6.4 years. Significantly, 55% of patients experienced symptoms before the age of 36 months. 3% never learned to sit unaided, a further 13% never gained the ability to walk independently and 33% of ambulatory patients lost this ability during the course of the disease. 43% developed scoliosis, 6.3% required non-invasive ventilation and 1.1% required tube feeding. In conclusion, our study, in line with previous observations, highlights the substantial phenotypic heterogeneity in SMA. Importantly, this study provides novel insights: the median age of disease onset in patients with 4 SMN2 copies typically occurs before school age, and in half of the patients even before the age of three years. These findings support a proactive approach, particularly early treatment initiation, in this subset of SMA patients diagnosed pre-symptomatically. However, it is important to recognize that the register will not include asymptomatic individuals.
Asunto(s)
Atrofia Muscular Espinal , Proteína 2 para la Supervivencia de la Neurona Motora , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Edad de Inicio , Austria/epidemiología , Progresión de la Enfermedad , Alemania , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/diagnóstico , Tamizaje Neonatal , Sistema de Registros , Estudios Retrospectivos , Proteína 2 para la Supervivencia de la Neurona Motora/genética , SuizaRESUMEN
Limb girdle muscular dystrophy type 2L or anoctaminopathy is a condition mainly characterized by adult onset proximal lower limb muscular weakness and raised CK values, due to recessive ANO5 gene mutations. An exon 5 founder mutation (c.191dupA) has been identified in most of the British and German LGMD2L patients so far reported. We aimed to further investigate the prevalence and spectrum of ANO5 gene mutations and related clinical phenotypes, by screening 205 undiagnosed patients referred to our molecular service with a clinical suspicion of anoctaminopathy. A total of 42 unrelated patients had two ANO5 mutations (21%), whereas 14 carried a single change. We identified 34 pathogenic changes, 15 of which are novel. The c.191dupA mutation represents 61% of mutated alleles and appears to be less prevalent in non-Northern European populations. Retrospective clinical analysis corroborates the prevalently proximal lower limb phenotype, the male predominance and absence of major cardiac or respiratory involvement. Identification of cases with isolated hyperCKaemia and very late symptomatic male and female subjects confirms the extension of the phenotypic spectrum of the disease. Anoctaminopathy appears to be one of the most common adult muscular dystrophies in Northern Europe, with a prevalence of about 20%-25% in unselected undiagnosed cases.
Asunto(s)
Canales de Cloruro/genética , Distrofia Muscular de Cinturas/genética , Mutación , Adulto , Anciano , Anoctaminas , Canales de Cloruro/metabolismo , Europa (Continente)/epidemiología , Femenino , Variación Genética , Humanos , Masculino , Persona de Mediana Edad , Distrofia Muscular de Cinturas/epidemiología , Distrofia Muscular de Cinturas/metabolismo , Fenotipo , Prevalencia , Estudios Retrospectivos , Factores SexualesRESUMEN
BACKGROUND AND OBJECTIVES: Disease progression in patients with spinal muscular atrophy (SMA) has changed dramatically within the past years due to the approval of three different disease-modifying treatments. Nusinersen was the first drug to be approved for the treatment of SMA patients. Clinical trials provided data from infants with SMA type 1 and children with SMA type 2, but there is still insufficient evidence and only scarcely reported long-term experience for nusinersen treatment in ambulant patients. Here, we report data from the SMArtCARE registry of ambulant patients under nusinersen treatment with a follow-up period of up to 38 months. METHODS: SMArtCARE is a disease-specific registry in Germany, Austria and Switzerland. Data are collected as real-world data during routine patient visits. Our analysis included all patients under treatment with nusinersen able to walk independently before start of treatment with focus on changes in motor function. RESULTS: Data from 231 ambulant patients were included in the analysis. During the observation period, 31 pediatric walkers (27.2%) and 31 adult walkers (26.5%) experienced a clinically meaningful improvement of≥30âm in the 6-Minute-Walk-Test. In contrast, only five adult walkers (7.7%) showed a decline in walking distance≥30âm, and two pediatric walkers (1.8%) lost the ability to walk unassisted under treatment with nusinersen. HFMSE and RULM scores improved in pediatric and remained stable in adult patients. CONCLUSION: Our data demonstrate a positive effect of nusinersen treatment in most ambulant pediatric and adult SMA patients. We not only observed a stabilization of disease progression or lack of deterioration, but clinically meaningful improvements in walking distance.
Asunto(s)
Atrofia Muscular Espinal , Atrofias Musculares Espinales de la Infancia , Lactante , Adulto , Niño , Humanos , Estudios Prospectivos , Atrofias Musculares Espinales de la Infancia/tratamiento farmacológico , Atrofia Muscular Espinal/tratamiento farmacológico , Caminata , Sistema de Registros , Progresión de la EnfermedadRESUMEN
OBJECTIVE: To determine whether a new indel mutation in the dimerization domain of filamin C (FLNc) causes a hereditary myopathy with protein aggregation in muscle fibers, we clinically and molecularly studied a German family with autosomal dominant myofibrillar myopathy (MFM). METHODS: We performed mutational analysis in 3 generations, muscle histopathology, and proteomic studies of IM protein aggregates. Functional consequences of the FLNC mutation were investigated with interaction and transfection studies and biophysics molecular analysis. RESULTS: Eight patients revealed clinical features of slowly progressive proximal weakness associated with a heterozygous c.8025_8030delCAAGACinsA (p.K2676Pfs*3) mutation in FLNC. Two patients exhibited a mild cardiomyopathy. MRI of skeletal muscle revealed lipomatous changes typical for MFM with FLNC mutations. Muscle biopsies showed characteristic MFM findings with protein aggregation and lesion formation. The proteomic profile of aggregates was specific for MFM-filaminopathy and indicated activation of the ubiquitin-proteasome system (UPS) and autophagic pathways. Functional studies revealed that mutant FLNc is misfolded, unstable, and incapable of forming homodimers and heterodimers with wild-type FLNc. CONCLUSIONS: This new MFM-filaminopathy family confirms that expression of mutant FLNC leads to an adult-onset muscle phenotype with intracellular protein accumulation. Mutant FLNc protein is biochemically compromised and leads to dysregulation of protein quality control mechanisms. Proteomic analysis of MFM protein aggregates is a potent method to identify disease-relevant proteins, differentiate MFM subtypes, evaluate the relevance of gene variants, and identify novel MFM candidate genes.
RESUMEN
OBJECTIVE: Several independent prognostic factors, such as age of onset, type of onset, body mass index (BMI), and progression rate have been identified for amyotrophic lateral sclerosis (ALS) in Caucasians. The aim of this study was to identify such factors in Chinese patients and to compare their impact with German patients. METHODS: Comparison of prognostic factors was based on two hospital-based registries. The registry of the German Network for Motor Neuron Diseases contains 3100 patients with ALS. The Chinese registry comprises 2101 patients who were collected between 2003 and 2015 in the metropolitan area of Beijing. RESULTS: Disease progression was slower in China [median loss of 0.50 points (IQR 0.26-0.87 points) versus 0.55 points (IQR 0.28-1.00 points) of ALS functional rating scale revised (ALS-FRS-R) score per month; p < 0.0001]. Survival of patients with ALS was similar in Germany and China (p > 0.05). We found that younger age of onset (p < 0.0001), spinal onset (p < 0.0001), high BMI (p < 0.0001) and low progression rate (p < 0.0001) were positive prognostic factors in China as well as in Germany. INTERPRETATION: Prognostic factors, which are known to modify the course of disease in Caucasians, apply to Chinese patients as well. The results indicate that despite the apparent differences regarding genotype and clinical phenotype, findings from interventional studies in Caucasians aiming at disease-modifying prognostic factors (such as body weight) may be transferred to Chinese patients.
Asunto(s)
Esclerosis Amiotrófica Lateral/epidemiología , Esclerosis Amiotrófica Lateral/fisiopatología , Progresión de la Enfermedad , Sistema de Registros , Edad de Inicio , Anciano , Esclerosis Amiotrófica Lateral/mortalidad , Beijing/epidemiología , Femenino , Alemania/epidemiología , Humanos , Masculino , PronósticoRESUMEN
We report a 36-year-old female having lifetime exercise intolerance and lactic acidosis with nausea associated with novel compound heterozygous Acyl-CoA dehydrogenase 9 gene (ACAD9) mutations (p.Ala390Thr and p.Arg518Cys). ACAD9 is an assembly factor for the mitochondrial respiratory chain complex I. ACAD9 mutations are recognized as frequent causes of complex I deficiency. Our patient presented with exercise intolerance, rapid fatigue, and nausea since early childhood. Mild physical workload provoked the occurrence of nausea and vomiting repeatedly. Her neurological examination, laboratory findings and muscle biopsy demonstrated no abnormalities. A bicycle spiroergometry provoked significant lactic acidosis during and following exercise pointing towards a mitochondrial disorder. Subsequently, the analysis of respiratory chain enzyme activities in muscle revealed severe isolated complex I deficiency. Candidate gene sequencing revealed two novel heterozygous ACAD9 mutations. This patient report expands the mutational and phenotypic spectrum of diseases associated with mutations in ACAD9.
Asunto(s)
Acidosis Láctica/genética , Acidosis Láctica/fisiopatología , Acil-CoA Deshidrogenasas/genética , Tolerancia al Ejercicio/genética , Enfermedades Mitocondriales/genética , Enfermedades Mitocondriales/fisiopatología , Acidosis Láctica/tratamiento farmacológico , Acidosis Láctica/patología , Adulto , Diagnóstico Diferencial , Complejo I de Transporte de Electrón/deficiencia , Tolerancia al Ejercicio/fisiología , Femenino , Heterocigoto , Humanos , Enfermedades Mitocondriales/tratamiento farmacológico , Enfermedades Mitocondriales/patología , Músculo Esquelético/patología , Mutación , FenotipoRESUMEN
Oculopharyngeal muscular dystrophy (OPMD) is a rare cause for late-onset dysphagia. OPMD normally follows an autosomal dominant inheritance. Herein we describe a rare case of an autosomal recessive inheritance of OPMD. An 80-year-old male presented with progressive dysphagia, frequent aspiration and change of voice getting inarticulate and hoarse. Physical examination showed ptosis of the right eyelid. Endoscopic and manometric investigation revealed a nonspecific motility disorder with hypopharyngeal esophageal hypotension. The severity of dysphagia became apparent when significant aspiration occurred during a barium swallow. Magnetic resonance imaging of the head ruled out a malignant or cerebral ischemic process. Based on the neurological examination, neurogenic muscular dystrophy was suspected and DNA analysis was performed. The analysis confirmed the extremely rare diagnosis of an autosomal recessive inheritance pattern of OPMD with homozygous (GCN)6(GCN)4(GCN) expansion of the poly-(A) binding protein nuclear 1 gene. As OPMD normally follows an autosomal dominant inheritance, consanguinity of the patient's parents was suspected.
RESUMEN
Weight loss is increasingly considered as a negative prognostic marker in amyotrophic lateral sclerosis (ALS). Despite the critical importance of nutritional issues in ALS, and the common use of percutaneous endoscopic gastrostomy (PEG), there is a general lack of knowledge on peri-interventional treatment, optimal parameters of enteral nutrition, its timing during disease progression and its potential disease-modifying effects in ALS patients. Here we report the results of a multi-center prospective study of percutaneous endoscopic gastrostomy (PEG) in ALS. In this observational clinical trial, 89 ALS patients were prospectively enrolled over a 3-year period and longitudinal data were collected over 18 months. PEG was a safe procedure even in patients with low forced vital capacity, and prophylactic single-shot antibiosis as well as slow increase of caloric nutrition via PEG was beneficial to avoid complications. No signs of refeeding syndrome were observed. High-caloric intake (>1,500 kcal/d) via PEG in patients that lived at least 12 months after PEG insertion was correlated with prolonged survival. Additional oral food intake was not associated with a worse prognosis. Our results suggest that peri-interventional PEG management should include prophylactic single-shot antibiosis, slow increase of caloric intake, and long-term high-caloric nutrition. Although our results indicate that PEG might be more beneficial when applied early, we believe that it can also be performed safely in patients with far advanced disease. Because of its explorative and observational character, most of our results have to be confirmed by a randomized interventional trial.
Asunto(s)
Esclerosis Amiotrófica Lateral/terapia , Nutrición Enteral/métodos , Gastroscopía/métodos , Gastrostomía/métodos , Anciano , Nutrición Enteral/efectos adversos , Femenino , Gastroscopía/efectos adversos , Gastrostomía/efectos adversos , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: Dysferlinopathies are autosomal recessive disorders caused by mutations in the dysferlin (DYSF) gene encoding the dysferlin protein. DYSF mutations lead to a wide range of muscular phenotypes, with the most prominent being Miyoshi myopathy (MM) and limb girdle muscular dystrophy type 2B (LGMD2B). METHODS: We assessed the one-year-natural course of dysferlinopathy, and the safety and efficacy of deflazacort treatment in a double-blind, placebo-controlled cross-over trial. After one year of natural course without intervention, 25 patients with genetically defined dysferlinopathy were randomized to receive deflazacort and placebo for six months each (1 mg/kg/day in month one, 1 mg/kg every 2nd day during months two to six) in one of two treatment sequences. RESULTS: During one year of natural course, muscle strength declined about 2% as measured by CIDD (Clinical Investigation of Duchenne Dystrophy) score, and 76 Newton as measured by hand-held dynamometry. Deflazacort did not improve muscle strength. In contrast, there is a trend of worsening muscle strength under deflazacort treatment, which recovers after discontinuation of the study drug. During deflazacort treatment, patients showed a broad spectrum of steroid side effects. CONCLUSION: Deflazacort is not an effective therapy for dysferlinopathies, and off-label use is not warranted. This is an important finding, since steroid treatment should not be administered in patients with dysferlinopathy, who may be often misdiagnosed as polymyositis. TRIAL REGISTRATION: This clinical trial was registered at http://www.ClincalTrials.gov, identifier: NCT00527228, and was always freely accessible to the public.