Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 337
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
N Engl J Med ; 390(21): 1985-1997, 2024 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-38838312

RESUMEN

BACKGROUND: Genetic variants that cause rare disorders may remain elusive even after expansive testing, such as exome sequencing. The diagnostic yield of genome sequencing, particularly after a negative evaluation, remains poorly defined. METHODS: We sequenced and analyzed the genomes of families with diverse phenotypes who were suspected to have a rare monogenic disease and for whom genetic testing had not revealed a diagnosis, as well as the genomes of a replication cohort at an independent clinical center. RESULTS: We sequenced the genomes of 822 families (744 in the initial cohort and 78 in the replication cohort) and made a molecular diagnosis in 218 of 744 families (29.3%). Of the 218 families, 61 (28.0%) - 8.2% of families in the initial cohort - had variants that required genome sequencing for identification, including coding variants, intronic variants, small structural variants, copy-neutral inversions, complex rearrangements, and tandem repeat expansions. Most families in which a molecular diagnosis was made after previous nondiagnostic exome sequencing (63.5%) had variants that could be detected by reanalysis of the exome-sequence data (53.4%) or by additional analytic methods, such as copy-number variant calling, to exome-sequence data (10.8%). We obtained similar results in the replication cohort: in 33% of the families in which a molecular diagnosis was made, or 8% of the cohort, genome sequencing was required, which showed the applicability of these findings to both research and clinical environments. CONCLUSIONS: The diagnostic yield of genome sequencing in a large, diverse research cohort and in a small clinical cohort of persons who had previously undergone genetic testing was approximately 8% and included several types of pathogenic variation that had not previously been detected by means of exome sequencing or other techniques. (Funded by the National Human Genome Research Institute and others.).


Asunto(s)
Variación Genética , Enfermedades Raras , Secuenciación Completa del Genoma , Femenino , Humanos , Masculino , Estudios de Cohortes , Exoma , Secuenciación del Exoma , Enfermedades Genéticas Congénitas/diagnóstico , Enfermedades Genéticas Congénitas/etnología , Enfermedades Genéticas Congénitas/genética , Pruebas Genéticas , Genoma Humano , Fenotipo , Enfermedades Raras/diagnóstico , Enfermedades Raras/etnología , Enfermedades Raras/genética , Análisis de Secuencia de ADN , Niño , Adolescente , Adulto Joven , Adulto
2.
Brain ; 147(8): 2867-2883, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38366623

RESUMEN

Alterations in RNA-splicing are a molecular hallmark of several neurological diseases, including muscular dystrophies, where mutations in genes involved in RNA metabolism or characterized by alterations in RNA splicing have been described. Here, we present five patients from two unrelated families with a limb-girdle muscular dystrophy (LGMD) phenotype carrying a biallelic variant in SNUPN gene. Snurportin-1, the protein encoded by SNUPN, plays an important role in the nuclear transport of small nuclear ribonucleoproteins (snRNPs), essential components of the spliceosome. We combine deep phenotyping, including clinical features, histopathology and muscle MRI, with functional studies in patient-derived cells and muscle biopsies to demonstrate that variants in SNUPN are the cause of a new type of LGMD according to current definition. Moreover, an in vivo model in Drosophila melanogaster further supports the relevance of Snurportin-1 in muscle. SNUPN patients show a similar phenotype characterized by proximal weakness starting in childhood, restrictive respiratory dysfunction and prominent contractures, although inter-individual variability in terms of severity even in individuals from the same family was found. Muscle biopsy showed myofibrillar-like features consisting of myotilin deposits and Z-disc disorganization. MRI showed predominant impairment of paravertebral, vasti, sartorius, gracilis, peroneal and medial gastrocnemius muscles. Conservation and structural analyses of Snurportin-1 p.Ile309Ser variant suggest an effect in nuclear-cytosol snRNP trafficking. In patient-derived fibroblasts and muscle, cytoplasmic accumulation of snRNP components is observed, while total expression of Snurportin-1 and snRNPs remains unchanged, which demonstrates a functional impact of SNUPN variant in snRNP metabolism. Furthermore, RNA-splicing analysis in patients' muscle showed widespread splicing deregulation, in particular in genes relevant for muscle development and splicing factors that participate in the early steps of spliceosome assembly. In conclusion, we report that SNUPN variants are a new cause of limb girdle muscular dystrophy with specific clinical, histopathological and imaging features, supporting SNUPN as a new gene to be included in genetic testing of myopathies. These results further support the relevance of splicing-related proteins in muscle disorders.


Asunto(s)
Distrofia Muscular de Cinturas , Humanos , Distrofia Muscular de Cinturas/genética , Distrofia Muscular de Cinturas/patología , Masculino , Femenino , Adulto , Animales , Músculo Esquelético/patología , Músculo Esquelético/metabolismo , Linaje , Drosophila melanogaster , Miofibrillas/patología , Miofibrillas/genética , Miofibrillas/metabolismo , Persona de Mediana Edad , Fenotipo , Adolescente , Adulto Joven , Niño
3.
Brain ; 2024 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-39045638

RESUMEN

Late-onset Pompe Disease (LOPD) is a rare genetic disorder caused by the deficiency of acid alpha-glucosidase leading to progressive cellular dysfunction due to the accumulation of glycogen in the lysosome. The mechanism of relentless muscle damage - a classic manifestation of the disease - has been extensively studied by analysing the whole muscle tissue; however, little, if any, is known about transcriptional heterogeneity among nuclei within the multinucleated skeletal muscle cells. This is the first report of application of single nuclei RNA sequencing to uncover changes in the gene expression profile in muscle biopsies from eight patients with LOPD and four muscle samples from age and gender matched healthy controls. We matched these changes with histology findings using GeoMx Spatial Transcriptomics to compare the transcriptome of control myofibers from healthy individuals with non-vacuolated (histologically unaffected) and vacuolated (histologically affected) myofibers of LODP patients. We observed an increase in the proportion of slow and regenerative muscle fibers and macrophages in LOPD muscles. The expression of the genes involved in glycolysis was reduced, whereas the expression of the genes involved in the metabolism of lipids and amino acids was increased in non-vacuolated fibers, indicating early metabolic abnormalities. Additionally, we detected upregulation of autophagy genes, and downregulation of the genes involved in ribosomal and mitochondrial function leading to defective oxidative phosphorylation. The upregulation of the genes associated with inflammation, apoptosis and muscle regeneration was observed only in vacuolated fibers. Notably, enzyme replacement therapy - the only available therapy for the disease - showed a tendency to restore metabolism dysregulation, particularly within slow fibers. A combination of single nuclei RNA sequencing and spatial transcriptomics revealed the landscape of normal and the diseased muscle, and highlighted the early abnormalities associated with the disease progression. Thus, the application of these two new cutting-edge technologies provided insight into the molecular pathophysiology of muscle damage in LOPD and identified potential avenues for therapeutic intervention.

4.
J Med Genet ; 2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39209426

RESUMEN

BACKGROUND: Weakness of facial, ocular and axial muscles is a common clinical presentation in congenital myopathies caused by pathogenic variants in genes encoding triad proteins. Abnormalities in triad structure and function resulting in disturbed excitation-contraction coupling and Ca2+ homeostasis can contribute to disease pathology. METHODS: We analysed exome and genome sequencing data from four unrelated individuals with congenital myopathy characterised by facial, ocular and bulbar involvement. We collected deep phenotypic data from the affected individuals. We analysed the RNA-sequencing (RNA-seq) data of F3-II.1 and performed gene expression outlier analysis in 129 samples. RESULTS: The four probands had a remarkably similar clinical presentation with prominent facial, ocular and bulbar features. Disease onset was in the neonatal period with hypotonia, poor feeding, cleft palate and talipes. Muscle weakness was generalised but prominent in the lower limbs with facial weakness also present. All patients had myopathic facies, bilateral ptosis, ophthalmoplegia and fatigability. Muscle biopsy on light microscopy showed type 1 myofiber predominance and ultrastructural analysis revealed slightly reduced triads, and structurally abnormal sarcoplasmic reticulum.DNA sequencing identified four unique homozygous loss-of-function variants in JPH1, encoding junctophilin-1 in the four families; one stop-gain (c.354C>A;p.Tyr118*) and three frameshift (c.373delG;p.Asp125Thrfs*30, c.1738delC;p.Leu580Trpfs*16 and c.1510delG;p. Glu504Serfs*3) variants. Muscle RNA-seq showed strong downregulation of JPH1 in the F3 proband. CONCLUSIONS: Junctophilin-1 is critical for the formation of skeletal muscle triad junctions by connecting the sarcoplasmic reticulum and T-tubules. Our findings suggest that loss of JPH1 results in a congenital myopathy with prominent facial, bulbar and ocular involvement.

5.
NMR Biomed ; : e5212, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39005110

RESUMEN

Duchenne muscular dystrophy (DMD) is a progressive X-linked neuromuscular disorder caused by the absence of functional dystrophin protein. In addition to muscle, dystrophin is expressed in the brain in both neurons and glial cells. Previous studies have shown altered white matter microstructure in patients with DMD using diffusion tensor imaging (DTI). However, DTI measures the diffusion properties of water, a ubiquitous molecule, making it difficult to unravel the underlying pathology. Diffusion-weighted spectroscopy (DWS) is a complementary technique which measures diffusion properties of cell-specific intracellular metabolites. Here we performed both DWS and DTI measurements to disentangle intra- and extracellular contributions to white matter changes in patients with DMD. Scans were conducted in patients with DMD (15.5 ± 4.6 y/o) and age- and sex-matched healthy controls (16.3 ± 3.3 y/o). DWS measurements were obtained in a volume of interest (VOI) positioned in the left parietal white matter. Apparent diffusion coefficients (ADCs) were calculated for total N-acetylaspartate (tNAA), choline compounds (tCho), and total creatine (tCr). The tNAA/tCr and tCho/tCr ratios were calculated from the non-diffusion-weighted spectrum. Mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD), and fractional anisotropy of water within the VOI were extracted from DTI measurements. DWS and DTI data from patients with DMD (respectively n = 20 and n = 18) and n = 10 healthy controls were included. No differences in metabolite ADC or in concentration ratios were found between patients with DMD and controls. In contrast, water diffusion (MD, t = -2.727, p = 0.011; RD, t = -2.720, p = 0.011; AD, t = -2.715, p = 0.012) within the VOI was significantly higher in patients compared with healthy controls. Taken together, our study illustrates the potential of combining DTI and DWS to gain a better understanding of microstructural changes and their association with disease mechanisms in a clinical setting.

6.
Muscle Nerve ; 2024 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-39072769

RESUMEN

INTRODUCTION/AIMS: Heterogeneous nuclear ribonucleoprotein A1 is involved in nucleic acid homeostatic functions. The encoding gene HNRNPA1 has been associated with several neuromuscular disorders including an amyotrophic lateral sclerosis-like phenotype, distal hereditary motor neuropathy, multisystem proteinopathy, and various myopathies. We report two unrelated individuals with monoallelic stop loss variants affecting the same codon of HNRNPA1. METHODS: Two individuals with unsolved juvenile-onset myopathy were enrolled under approved institutional protocols. Phenotype data were collected and genetic analyses were performed, including whole-exome sequencing (WES). RESULTS: The two probands (MNOT002-01 and K1440-01) showed a similar onset of slowly progressive extremity and facial weakness in early adolescence. K1440-01 presented with facial weakness, winged scapula, elevated serum creatine kinase (CK) levels, and mild neck weakness. MNOT002-01 also exhibited elevated CK levels along with facial weakness, cardiomyopathy, respiratory dysfunction, pectus excavatum, a mildly rigid spine, and loss of ambulation. On quadriceps muscle biopsy, K1440-01 displayed rounded myofibers, mild variation in fiber diameter, and type 2 fiber hypertrophy, while MNOT002-01 displayed rimmed vacuoles. Monoallelic stop-loss variants in HNRNPA1 were identified for both probands: c.1119A>C p.*373Tyrext*6 (K1440-01) and c.1118A>C p.*373Serext*6 (MNOT002-01) affect the same codon and are both predicted to lead to the addition of six amino acids before termination at an alternative stop codon. DISCUSSION: Both stop-loss variants in our probands are likely pathogenic. Our findings contribute to the disease characterization of pathogenic variants in HNRNPA1. This gene should be screened in clinical diagnostic testing of unsolved cases of sporadic or dominant juvenile-onset myopathy.

7.
Eur J Neurol ; 31(6): e16267, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38556893

RESUMEN

BACKGROUND AND PURPOSE: The transition to adult services, and subsequent glucocorticoid management, is critical in adults with Duchenne muscular dystrophy. This study aims (1) to describe treatment, functional abilities, respiratory and cardiac status during transition to adulthood and adult stages; and (2) to explore the association between glucocorticoid treatment after loss of ambulation (LOA) and late-stage clinical outcomes. METHODS: This was a retrospective single-centre study on individuals with Duchenne muscular dystrophy (≥16 years old) between 1986 and 2022. Logistic regression, Cox proportional hazards models and survival analyses were conducted utilizing data from clinical records. RESULTS: In all, 112 individuals were included. Mean age was 23.4 ± 5.2 years and mean follow-up was 18.5 ± 5.5 years. At last assessment, 47.2% were on glucocorticoids; the mean dose of prednisone was 0.38 ± 0.13 mg/kg/day and of deflazacort 0.43 ± 0.16 mg/kg/day. At age 16 years, motor function limitations included using a manual wheelchair (89.7%), standing (87.9%), transferring from a wheelchair (86.2%) and turning in bed (53.4%); 77.5% had a peak cough flow <270 L/min, 53.3% a forced vital capacity percentage of predicted <50% and 40.3% a left ventricular ejection fraction <50%. Glucocorticoids after LOA reduced the risk and delayed the time to difficulties balancing in the wheelchair, loss of hand to mouth function, forced vital capacity percentage of predicted <30% and forced vital capacity <1 L and were associated with lower frequency of left ventricular ejection fraction <50%, without differences between prednisone and deflazacort. Glucocorticoid dose did not differ by functional, respiratory or cardiac status. CONCLUSION: Glucocorticoids after LOA preserve late-stage functional abilities, respiratory and cardiac function. It is suggested using functional abilities, respiratory and cardiac status at transition stages for adult services planning.


Asunto(s)
Glucocorticoides , Distrofia Muscular de Duchenne , Humanos , Distrofia Muscular de Duchenne/tratamiento farmacológico , Distrofia Muscular de Duchenne/fisiopatología , Masculino , Adulto , Glucocorticoides/uso terapéutico , Adulto Joven , Estudios Retrospectivos , Adolescente , Femenino , Pregnenodionas/uso terapéutico , Prednisona/uso terapéutico , Limitación de la Movilidad , Estudios de Cohortes , Corazón/efectos de los fármacos , Corazón/fisiopatología
8.
Int J Mol Sci ; 25(14)2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-39063034

RESUMEN

Duchenne and Becker muscular dystrophies, caused by pathogenic variants in DMD, are the most common inherited neuromuscular conditions in childhood. These diseases follow an X-linked recessive inheritance pattern, and mainly males are affected. The most prevalent pathogenic variants in the DMD gene are copy number variants (CNVs), and most patients achieve their genetic diagnosis through Multiplex Ligation-dependent Probe Amplification (MLPA) or exome sequencing. Here, we investigated a female patient presenting with muscular dystrophy who remained genetically undiagnosed after MLPA and exome sequencing. RNA sequencing (RNAseq) from the patient's muscle biopsy identified an 85% reduction in DMD expression compared to 116 muscle samples included in the cohort. A de novo balanced translocation between chromosome 17 and the X chromosome (t(X;17)(p21.1;q23.2)) disrupting the DMD and BCAS3 genes was identified through trio whole genome sequencing (WGS). The combined analysis of RNAseq and WGS played a crucial role in the detection and characterisation of the disease-causing variant in this patient, who had been undiagnosed for over two decades. This case illustrates the diagnostic odyssey of female DMD patients with complex structural variants that are not detected by current panel or exome sequencing analysis.


Asunto(s)
Cromosomas Humanos X , Distrofina , Genómica , Distrofia Muscular de Duchenne , Translocación Genética , Humanos , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/diagnóstico , Femenino , Distrofina/genética , Cromosomas Humanos X/genética , Genómica/métodos , Variaciones en el Número de Copia de ADN , Secuenciación del Exoma , Transcriptoma/genética , Cromosomas Humanos Par 17/genética
9.
Am J Hum Genet ; 107(6): 1078-1095, 2020 12 03.
Artículo en Inglés | MEDLINE | ID: mdl-33217308

RESUMEN

The myosin-directed chaperone UNC-45B is essential for sarcomeric organization and muscle function from Caenorhabditis elegans to humans. The pathological impact of UNC-45B in muscle disease remained elusive. We report ten individuals with bi-allelic variants in UNC45B who exhibit childhood-onset progressive muscle weakness. We identified a common UNC45B variant that acts as a complex hypomorph splice variant. Purified UNC-45B mutants showed changes in folding and solubility. In situ localization studies further demonstrated reduced expression of mutant UNC-45B in muscle combined with abnormal localization away from the A-band towards the Z-disk of the sarcomere. The physiological relevance of these observations was investigated in C. elegans by transgenic expression of conserved UNC-45 missense variants, which showed impaired myosin binding for one and defective muscle function for three. Together, our results demonstrate that UNC-45B impairment manifests as a chaperonopathy with progressive muscle pathology, which discovers the previously unknown conserved role of UNC-45B in myofibrillar organization.


Asunto(s)
Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/fisiología , Chaperonas Moleculares/genética , Chaperonas Moleculares/fisiología , Enfermedades Musculares/genética , Mutación Missense , Adolescente , Adulto , Alelos , Animales , Caenorhabditis elegans , Femenino , Variación Genética , Humanos , Mutación con Pérdida de Función , Masculino , Músculo Esquelético/patología , Miofibrillas , Miosinas , Sarcómeros/metabolismo , Análisis de Secuencia de ARN , Transgenes , Secuenciación del Exoma , Adulto Joven
10.
Curr Opin Neurol ; 36(5): 450-454, 2023 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-37591308

RESUMEN

PURPOSE OF REVIEW: The purpose of this review is to summarise the recent developments in trial readiness, natural history studies, and interventional clinical trials for Becker muscular dystrophy (BMD). RECENT FINDINGS: As several treatment concepts have claimed to convert patients with Duchenne muscular dystrophy (DMD) into a BMD phenotype, BMD itself has moved into the focus of clinical research. Natural history studies have helped to better characterize patients with BMD and the disease is now a target for interventional trials. In parallel, there have been advances in diagnostics and in the development of preclinical models. SUMMARY: Despite increased collaborative efforts to improve trial readiness amongst patients with BMD, there is still a lack of long-term natural history data, and the broad spectrum of disease severity remains a challenge for well designed clinical trials.


Asunto(s)
Distrofia Muscular de Duchenne , Humanos , Distrofia Muscular de Duchenne/diagnóstico , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/terapia , Fenotipo , Proyectos de Investigación
11.
Acta Neuropathol ; 145(1): 127-143, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36264506

RESUMEN

DNAJ/HSP40 co-chaperones are integral to the chaperone network, bind client proteins and recruit them to HSP70 for folding. We performed exome sequencing on patients with a presumed hereditary muscle disease and no genetic diagnosis. This identified four individuals from three unrelated families carrying an unreported homozygous stop gain (c.856A > T; p.Lys286Ter), or homozygous missense variants (c.74G > A; p.Arg25Gln and c.785 T > C; p.Leu262Ser) in DNAJB4. Affected patients presented with axial rigidity and early respiratory failure requiring ventilator support between the 1st and 4th decade of life. Selective involvement of the semitendinosus and biceps femoris muscles was seen on MRI scans of the thigh. On biopsy, muscle was myopathic with angular fibers, protein inclusions and occasional rimmed vacuoles. DNAJB4 normally localizes to the Z-disc and was absent from muscle and fibroblasts of affected patients supporting a loss of function. Functional studies confirmed that the p.Lys286Ter and p.Leu262Ser mutant proteins are rapidly degraded in cells. In contrast, the p.Arg25Gln mutant protein is stable but failed to complement for DNAJB function in yeast, disaggregate client proteins or protect from heat shock-induced cell death consistent with its loss of function. DNAJB4 knockout mice had muscle weakness and fiber atrophy with prominent diaphragm involvement and kyphosis. DNAJB4 knockout muscle and myotubes had myofibrillar disorganization and accumulated Z-disc proteins and protein chaperones. These data demonstrate a novel chaperonopathy associated with DNAJB4 causing a myopathy with early respiratory failure. DNAJB4 loss of function variants may lead to the accumulation of DNAJB4 client proteins resulting in muscle dysfunction and degeneration.


Asunto(s)
Enfermedades Musculares , Insuficiencia Respiratoria , Animales , Ratones , Mutación/genética , Enfermedades Musculares/diagnóstico por imagen , Enfermedades Musculares/genética , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Mutación Missense , Insuficiencia Respiratoria/genética , Insuficiencia Respiratoria/complicaciones , Insuficiencia Respiratoria/patología , Músculo Esquelético/patología
12.
Brain ; 145(2): 596-606, 2022 04 18.
Artículo en Inglés | MEDLINE | ID: mdl-34515763

RESUMEN

Sarcoglycanopathies include four subtypes of autosomal recessive limb-girdle muscular dystrophies (LGMDR3, LGMDR4, LGMDR5 and LGMDR6) that are caused, respectively, by mutations in the SGCA, SGCB, SGCG and SGCD genes. Delta-sarcoglycanopathy (LGMDR6) is the least frequent and is considered an ultra-rare disease. Our aim was to characterize the clinical and genetic spectrum of a large international cohort of LGMDR6 patients and to investigate whether or not genetic or protein expression data could predict a disease's severity. This is a retrospective study collecting demographic, genetic, clinical and histological data of patients with genetically confirmed LGMDR6 including protein expression data from muscle biopsies. We contacted 128 paediatric and adult neuromuscular units around the world that reviewed genetic data of patients with a clinical diagnosis of a neuromuscular disorder. We identified 30 patients with a confirmed diagnosis of LGMDR6 of which 23 patients were included in this study. Eighty-seven per cent of the patients had consanguineous parents. Ninety-one per cent of the patients were symptomatic at the time of the analysis. Proximal muscle weakness of the upper and lower limbs was the most common presenting symptom. Distal muscle weakness was observed early over the course of the disease in 56.5% of the patients. Cardiac involvement was reported in five patients (21.7%) and four patients (17.4%) required non-invasive ventilation. Sixty per cent of patients were wheelchair-bound since early teens (median age of 12.0 years). Patients with absent expression of the sarcoglycan complex on muscle biopsy had a significant earlier onset of symptoms and an earlier age of loss of ambulation compared to patients with residual protein expression. This study confirmed that delta-sarcoglycanopathy is an ultra-rare neuromuscular condition and described the clinical and molecular characteristics of the largest yet-reported collected cohort of patients. Our results showed that this is a very severe and quickly progressive disease characterized by generalized muscle weakness affecting predominantly proximal and distal muscles of the limbs. Similar to other forms of sarcoglycanopathies, the severity and rate of progressive weakness correlates inversely with the abundance of protein on muscle biopsy.


Asunto(s)
Distrofia Muscular de Cinturas , Distrofias Musculares , Sarcoglicanopatías , Adulto , Niño , Humanos , Debilidad Muscular , Distrofias Musculares/genética , Distrofia Muscular de Cinturas/diagnóstico , Distrofia Muscular de Cinturas/genética , Estudios Retrospectivos , Sarcoglicanopatías/genética , Sarcoglicanos/genética , Sarcoglicanos/metabolismo
13.
J Med Genet ; 59(11): 1069-1074, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35393337

RESUMEN

BACKGROUND: Biallelic pathogenic variants in FXR1 have recently been associated with two congenital myopathy phenotypes: a severe form associated with hypotonia, long bone fractures, respiratory insufficiency and infantile death, and a milder form characterised by proximal muscle weakness with survival into adulthood. OBJECTIVE: We report eight patients from four unrelated families with biallelic pathogenic variants in exon 15 of FXR1. METHODS: Whole exome sequencing was used to detect variants in FXR1. RESULTS: Common clinical features were noted for all patients, which included proximal myopathy, normal serum creatine kinase levels and diffuse muscle atrophy with relative preservation of the quadriceps femoris muscle on muscle imaging. Additionally, some patients with FXR1-related myopathy had respiratory involvement and required bilevel positive airway pressure support. Muscle biopsy showed multi-minicores and type I fibre predominance with internalised nuclei. CONCLUSION: FXR1-related congenital myopathy is an emerging entity that is clinically recognisable. Phenotypic variability associated with variants in FXR1 can result from differences in variant location and type and is also observed between patients homozygous for the same variant, rendering specific genotype-phenotype correlations difficult. Our work broadens the phenotypic spectrum of FXR1-related congenital myopathy.


Asunto(s)
Enfermedades Musculares , Humanos , Linaje , Mutación , Enfermedades Musculares/diagnóstico , Enfermedades Musculares/genética , Homocigoto , Creatina Quinasa/genética , Proteínas de Unión al ARN/genética
14.
Int J Health Plann Manage ; 38(2): 416-429, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36335084

RESUMEN

INTRODUCTION: The conect4children (c4c) consortium was setup to facilitate the development of new drugs and therapies for paediatric populations and address key challenges associated with paediatric clinical trials. Two of the major adopting principles for c4c were academia-industry partnership and data harmonisation and interoperability through common eCRF definitions. To understand the challenges arising out of these principles, the c4c team at Newcastle University conducted semi-structured interviews with four c4c industry partners. METHODS: Each partner was asked 10 questions about the data standards used in their company, management and maintenance of data dictionaries, how they dealt with paediatric-specific issues, major knowledge gaps and how academia could aid in bridging these gaps. Thematic analysis was performed to identify patterns in their answers. RESULTS: All companies use the Clinical Data Interchange Standards Consortium (CDISC) standards but face problems when certain terminology is not included in CDISC (e.g., paediatric-specific terminologies). All companies were committed to interoperability and had strict policies about how additional terminology could be added to their dictionaries. Three of the four companies maintained a single dictionary but also had lighter versions for specific usage. The two major knowledge gaps identified from the interviews were handling of non-CDISC terminology and maintenance of normal lab ranges in dictionaries. DISCUSSION: To address these gaps, c4c has been working on a four-point plan including the development of a cross-cutting paediatric dictionary and a paediatric user guide in collaboration with CDISC.


Asunto(s)
Desarrollo de Medicamentos , Asociación entre el Sector Público-Privado , Niño , Humanos , Investigación Cualitativa , Ensayos Clínicos como Asunto
15.
Hum Mutat ; 43(9): 1234-1238, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35607917

RESUMEN

Emery-Dreifuss muscular dystrophy (EDMD) is a hereditary muscle disease, characterized by the clinical triade of early-onset joint contractures, progressive muscle weakness, and cardiac involvement. Pathogenic variants in FHL1 can cause a rare X-linked recessive form of EDMD, type 6. We report three men with novel variants in FHL1 leading to EDMD6. The onset of muscle symptoms was in late adulthood and muscle weakness was not prominent in either of the patients. All patients had hypertrophic cardiomyopathy and one of them also had cardiac arrhythmias. Western blot performed on muscle biopsies from two of the patients showed no FHL1 protein expression. We predict that the variant in the third patient also leads to the absence of FHL1 protein. Complete loss of all FHL1 isoforms combined with mild muscle involvement supports the hypothesis that loss of all FHL1 isoforms is more benign than the cytotoxic effects of expressed FHL1 protein with pathogenic missense variants.


Asunto(s)
Péptidos y Proteínas de Señalización Intracelular , Proteínas con Dominio LIM , Proteínas Musculares , Distrofia Muscular de Emery-Dreifuss , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Proteínas con Dominio LIM/genética , Masculino , Proteínas Musculares/genética , Distrofia Muscular de Emery-Dreifuss/diagnóstico , Distrofia Muscular de Emery-Dreifuss/genética , Fenotipo , Isoformas de Proteínas/genética
16.
Neuropathol Appl Neurobiol ; 48(7): e12846, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-35962550

RESUMEN

AIMS: Dysferlinopathy is an autosomal recessive muscular dystrophy, caused by bi-allelic variants in the gene encoding dysferlin (DYSF). Onset typically occurs in the second to third decade and is characterised by slowly progressive skeletal muscle weakness and atrophy of the proximal and/or distal muscles of the four limbs. There are rare cases of symptomatic DYSF variant carriers. Here, we report a large family with a dominantly inherited hyperCKaemia and late-onset muscular dystrophy. METHODS AND RESULTS: Genetic analysis identified a co-segregating novel DYSF variant [NM_003494.4:c.6207del p.(Tyr2070Metfs*4)]. No secondary variants in DYSF or other dystrophy-related genes were identified on whole genome sequencing and analysis of the proband's DNA. Skeletal muscle involvement was milder and later onset than typical dysferlinopathy presentations; these clinical signs manifested in four individuals, all between the fourth and sixth decades of life. All individuals heterozygous for the c.6207del variant had hyperCKaemia. Histological analysis of skeletal muscle biopsies across three generations showed clear dystrophic signs, including inflammatory infiltrates, regenerating myofibres, increased variability in myofibre size and internal nuclei. Muscle magnetic resonance imaging revealed fatty replacement of muscle in two individuals. Western blot and immunohistochemical analysis of muscle biopsy demonstrated consistent reduction of dysferlin staining. Allele-specific quantitative PCR analysis of DYSF mRNA from patient muscle found that the variant, localised to the extreme C-terminus of dysferlin, does not activate post-transcriptional mRNA decay. CONCLUSIONS: We propose that this inheritance pattern may be underappreciated and that other late-onset muscular dystrophy cases with mono-allelic DYSF variants, particularly C-terminal premature truncation variants, may represent dominant forms of disease.


Asunto(s)
Disferlina , Distrofia Muscular de Cinturas , Distrofias Musculares , Humanos , Disferlina/genética , Proteínas de la Membrana/genética , Proteínas Musculares/genética , Músculo Esquelético/patología , Distrofia Muscular de Cinturas/genética , Linaje , Masculino , Femenino
17.
Ann Neurol ; 89(5): 967-978, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33576057

RESUMEN

OBJECTIVE: Dysferlinopathy is a muscular dystrophy with a highly variable clinical presentation and currently unpredictable progression. This variability and unpredictability presents difficulties for prognostication and clinical trial design. The Jain Clinical Outcomes Study of Dysferlinopathy aims to establish the validity of the North Star Assessment for Limb Girdle Type Muscular Dystrophies (NSAD) scale and identify factors that influence the rate of disease progression using NSAD. METHODS: We collected a longitudinal series of functional assessments from 187 patients with dysferlinopathy over 3 years. Rasch analysis was used to develop the NSAD, a motor performance scale suitable for ambulant and nonambulant patients. Generalized estimating equations were used to evaluate the impact of patient factors on outcome trajectories. RESULTS: The NSAD detected significant change in clinical progression over 1 year. The steepest functional decline occurred during the first 10 years after symptom onset, with more rapid decline noted in patients who developed symptoms at a younger age (p = 0.04). The most rapidly deteriorating group over the study was patients 3 to 8 years post symptom onset at baseline. INTERPRETATION: The NSAD is the first validated limb girdle specific scale of motor performance, suitable for use in clinical practice and clinical trials. Longitudinal analysis showed it may be possible to identify patient factors associated with greater functional decline both across the disease course and in the short-term for clinical trial preparation. Through further work and validation in this cohort, we anticipate that a disease model incorporating functional performance will allow for more accurate prognosis for patients with dysferlinopathy. ANN NEUROL 2021;89:967-978.


Asunto(s)
Distrofia Muscular de Cinturas/diagnóstico , Adolescente , Adulto , Edad de Inicio , Anciano , Anciano de 80 o más Años , Niño , Ensayos Clínicos como Asunto/métodos , Estudios de Cohortes , Progresión de la Enfermedad , Femenino , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Distrofia Muscular de Cinturas/fisiopatología , Distrofia Muscular de Cinturas/psicología , Psicometría , Resultado del Tratamiento , Adulto Joven
18.
Muscle Nerve ; 65(1): 67-74, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34606104

RESUMEN

INTRODUCTION/AIMS: Mutations amenable to skipping of specific exons have been associated with different motor progression in Duchenne muscular dystrophy (DMD). Less is known about their association with long-term respiratory function. In this study we investigated the features of respiratory progression in four DMD genotypes relevant in ongoing exon-skipping therapeutic strategies. METHODS: This was a retrospective longitudinal study including DMD children followed by the UK NorthStar Network and international AFM Network centers (May 2003 to October 2020). We included boys amenable to skip exons 44, 45, 51, or 53, who were older than 5 years of age and ambulant at first recorded visit. Subjects who were corticosteroid-naive or enrolled in interventional clinical trials were excluded. The progression of respiratory function (absolute forced vital capacity [FVC] and calculated as percent predicted [FVC%]) was compared across the four subgroups (skip44, skip45, skip51, skip53). RESULTS: We included 142 boys in the study. Mean (standard deviation) age at first visit was 8.6 (2.5) years. Median follow-up was 3 (range, 0.3-8.3) years. In skip45 and skip51, FVC% declined linearly from the first recorded visit. From the age of 9 years, FVC% declined linearly in all genotypes. Skip44 had the slowest (2.7%/year) and skip51 the fastest (5.9%/year) annual FVC% decline. The absolute FVC increased progressively in skip44, skip45, and skip51. In skip53, FVC started declining from 14 years of age. DISCUSSION: The progression of respiratory dysfunction follows different patterns for specific genotype categories. This information is valuable for prognosis and for the evaluation of exon-skipping therapies.


Asunto(s)
Distrofia Muscular de Duchenne , Niño , Exones , Genotipo , Humanos , Estudios Longitudinales , Masculino , Estudios Retrospectivos
19.
Muscle Nerve ; 66(2): 159-166, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35506767

RESUMEN

INTRODUCTION/AIMS: Dysferlinopathy demonstrates heterogeneity in muscle weakness between patients, which can progress at different rates over time. Changing muscle strength due to disease progression or from an investigational product is associated with changing functional ability. The purpose of this study was to compare three methods of strength testing used in the Clinical Outcome Study (COS) for dysferlinopathy to understand which method and which muscle groups were most sensitive to change over time. METHODS: Patients were evaluated at each study visit using functional scales, manual muscle testing, and handheld dynamometry (HHD) at all 15 sites. A fixed-frame system (Fixed) was used at a subset of seven sites. Screening and baseline visits were evaluated for reliability. Data over a 1-year period were analyzed to determine sensitivity to change among strength modalities and individual muscle groups. RESULTS: HHD and Fixed captured significant change across 1 year in summed muscle strength score of four muscle groups (P < .01). Strength summed scores were significantly correlated with functional scales (rho = 0.68-0.92, P < .001). Individual muscle groups, however, showed high levels of variability between visits. DISCUSSION: Although both HHD and Fixed demonstrate change over 12 months, HHD is a less expensive option that provides data on a continuous scale and may be easier to implement. Due to variability in strength measures, researchers should carefully consider use of strength testing as an outcome and may wish to select functional measures with less variability as clinical trial endpoints.


Asunto(s)
Fuerza Muscular , Distrofia Muscular de Cinturas , Humanos , Fuerza Muscular/fisiología , Dinamómetro de Fuerza Muscular , Distrofia Muscular de Cinturas/diagnóstico , Reproducibilidad de los Resultados
20.
Muscle Nerve ; 65(5): 531-540, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35179231

RESUMEN

INTRODUCTION/AIMS: There is debate about whether and to what extent either respiratory or cardiac dysfunction occurs in patients with dysferlinopathy. This study aimed to establish definitively whether dysfunction in either system is part of the dysferlinopathy phenotype. METHODS: As part of the Jain Foundation's International Clinical Outcome Study (COS) for dysferlinopathy, objective measures of respiratory and cardiac function were collected twice, with a 3-y interval between tests, in 188 genetically confirmed patients aged 11-86 y (53% female). Measures included forced vital capacity (FVC), electrocardiogram (ECG), and echocardiogram (echo). RESULTS: Mean FVC was 90% predicted at baseline, decreasing to 88% at year 3. FVC was less than 80% predicted in 44 patients (24%) at baseline and 48 patients (30%) by year 3, including ambulant participants. ECGs showed P-wave abnormalities indicative of delayed trans-atrial conduction in 58% of patients at baseline, representing a risk for developing atrial flutter or fibrillation. The prevalence of impaired left ventricular function or hypertrophy was comparable to that in the general population. DISCUSSION: These results demonstrate clinically significant respiratory impairment and abnormal atrial conduction in some patients with dysferlinopathy. Therefore, we recommend that annual or biannual follow-up should include FVC measurement, enquiry about arrhythmia symptoms and peripheral pulse palpation to assess cardiac rhythm. However, periodic specialist cardiac review is probably not warranted unless prompted by symptoms or abnormal pulse findings.


Asunto(s)
Distrofia Muscular de Cinturas , Electrocardiografía , Femenino , Humanos , Estudios Longitudinales , Masculino , Distrofia Muscular de Cinturas/genética , Fenotipo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA