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1.
Int J Mol Sci ; 25(8)2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38673950

RESUMEN

Demyelinating Charcot-Marie-Tooth 4G (CMT4G) results from a recessive mutation in the 5'UTR region of the Hexokinase 1 (HK1) gene. HK participates in mitochondrial calcium homeostasis by binding to the Voltage-Dependent Anion Channel (VDAC), through its N-terminal porin-binding domain. Our hypothesis is that CMT4G mutation results in a broken interaction between mutant HK1 and VDAC, disturbing mitochondrial calcium homeostasis. We studied a cohort of 25 CMT4G patients recruited in the French gypsy population. The disease was characterized by a childhood onset, an intermediate demyelinating pattern, and a significant phenotype leading to becoming wheelchair-bound by the fifth decade of life. Co-IP and PLA studies indicated a strong decreased interaction between VDAC and HK1 in the patients' PBMCs and sural nerve. We observed that either wild-type HK1 expression or a peptide comprising the 15 aa of the N-terminal wild-type HK1 administration decreased mitochondrial calcium release in HEK293 cells. However, mutated CMT4G HK1 or the 15 aa of the mutated HK1 was unable to block mitochondrial calcium release. Taken together, these data show that the CMT4G-induced modification of the HK1 N-terminus disrupts HK1-VDAC interaction. This alters mitochondrial calcium buffering that has been shown to be critical for myelin sheath maintenance.


Asunto(s)
Calcio , Enfermedad de Charcot-Marie-Tooth , Hexoquinasa , Mitocondrias , Canal Aniónico 1 Dependiente del Voltaje , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , Regiones no Traducidas 5'/genética , Calcio/metabolismo , Enfermedad de Charcot-Marie-Tooth/genética , Enfermedad de Charcot-Marie-Tooth/metabolismo , Células HEK293 , Hexoquinasa/genética , Hexoquinasa/metabolismo , Mitocondrias/metabolismo , Mitocondrias/genética , Mutación , Unión Proteica , Canal Aniónico 1 Dependiente del Voltaje/metabolismo , Canal Aniónico 1 Dependiente del Voltaje/genética
3.
Dev Med Child Neurol ; 66(8): 1053-1061, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38263722

RESUMEN

AIM: To compare the efficacy of intravenous clonazepam (CLZ) for the initial management of convulsive status epilepticus (CSE) in children as a function of the first-line in-hospital dose used. METHOD: This monocentric retrospective study included children who received a first dose of CLZ for CSE at Montpellier University Hospital, France, between January 2016 and June 2019. Data from medical records (clinical, treatment, course) were collected and compared as a function of the first CLZ dose used. RESULTS: Among the 310 children treated for CSE, 105 received at least one CLZ dose (median age 3 years; quartile 1-quartile 3 [Q1-Q3] = 1 years 2 months-6 years 6 months). Among these 105 patients, 24 (22%) received a dose less than 0.03 mg/kg (low dose) and 69 (65%) received a dose of at least 0.03 mg/kg (high dose). Seizure cessation rate was not different between the low- and high-dose groups (62.5% vs 76%; odds ratio 0.53, 95% confidence interval [CI] 0.19-1.44, p = 0.29). The administration of a second dose of CLZ was more frequent in the low- than the high-dose group (37.5% vs 16%; odds ratio 3.2, 95% CI 1.1-9.1, p = 0.04). INTERPRETATION: Our study did not find any difference in seizure termination rate as a function of CLZ dose in children with CSE. However, a second CLZ dose was more frequently needed in the group receiving low (less than 0.03 mg/kg) CLZ.


Asunto(s)
Administración Intravenosa , Anticonvulsivantes , Clonazepam , Estado Epiléptico , Humanos , Estado Epiléptico/tratamiento farmacológico , Masculino , Femenino , Clonazepam/administración & dosificación , Estudios Retrospectivos , Preescolar , Niño , Anticonvulsivantes/administración & dosificación , Lactante , Resultado del Tratamiento , Relación Dosis-Respuesta a Droga
4.
J Cachexia Sarcopenia Muscle ; 15(2): 536-551, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38221511

RESUMEN

BACKGROUND: Duchenne muscular dystrophy (DMD) is an X-linked disorder characterized by progressive muscle weakness due to the absence of functional dystrophin. DMD patients also develop dilated cardiomyopathy (DCM). We have previously shown that DMD (mdx) mice and a canine DMD model (GRMD) exhibit abnormal intracellular calcium (Ca2+) cycling related to early-stage pathological remodelling of the ryanodine receptor intracellular calcium release channel (RyR2) on the sarcoplasmic reticulum (SR) contributing to age-dependent DCM. METHODS: Here, we used hiPSC-CMs from DMD patients selected by Speckle-tracking echocardiography and canine DMD cardiac biopsies to assess key early-stage Duchenne DCM features. RESULTS: Dystrophin deficiency was associated with RyR2 remodelling and SR Ca2+ leak (RyR2 Po of 0.03 ± 0.01 for HC vs. 0.16 ± 0.01 for DMD, P < 0.01), which led to early-stage defects including senescence. We observed higher levels of senescence markers including p15 (2.03 ± 0.75 for HC vs. 13.67 ± 5.49 for DMD, P < 0.05) and p16 (1.86 ± 0.83 for HC vs. 10.71 ± 3.00 for DMD, P < 0.01) in DMD hiPSC-CMs and in the canine DMD model. The fibrosis was increased in DMD hiPSC-CMs. We observed cardiac hypocontractility in DMD hiPSC-CMs. Stabilizing RyR2 pharmacologically by S107 prevented most of these pathological features, including the rescue of the contraction amplitude (1.65 ± 0.06 µm for DMD vs. 2.26 ± 0.08 µm for DMD + S107, P < 0.01). These data were confirmed by proteomic analyses, in particular ECM remodelling and fibrosis. CONCLUSIONS: We identified key cellular damages that are established earlier than cardiac clinical pathology in DMD patients, with major perturbation of the cardiac ECC. Our results demonstrated that cardiac fibrosis and premature senescence are induced by RyR2 mediated SR Ca2+ leak in DMD cardiomyocytes. We revealed that RyR2 is an early biomarker of DMD-associated cardiac damages in DMD patients. The progressive and later DCM onset could be linked with the RyR2-mediated increased fibrosis and premature senescence, eventually causing cell death and further cardiac fibrosis in a vicious cycle leading to further hypocontractility as a major feature of DCM. The present study provides a novel understanding of the pathophysiological mechanisms of the DMD-induced DCM. By targeting RyR2 channels, it provides a potential pharmacological treatment.


Asunto(s)
Cardiomiopatías , Cardiomiopatía Dilatada , Humanos , Ratones , Animales , Perros , Cardiomiopatía Dilatada/etiología , Distrofina/genética , Distrofina/metabolismo , Canal Liberador de Calcio Receptor de Rianodina/genética , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Ratones Endogámicos mdx , Calcio/metabolismo , Proteómica , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Fibrosis
5.
Dev Med Child Neurol ; 66(2): 176-186, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37501281

RESUMEN

AIM: To study long-term sequelae in children with Guillain-Barré syndrome (GBS). METHOD: This was a prospective observational study with children from two French tertiary centres. Data were from clinical and several standardized scales or questionnaires. RESULTS: Fifty-one patients were included with a median follow-up of 6 years 4 months (range 3-20 years) after the acute phase. The sequelae rate was 67% (95% confidence interval [CI] 53-78) and did not vary with time. Most children had minor sequelae (Guillain-Barré Syndrome Disability Score [GBSDS] = 1); only one was unable to run (GBSDS = 2). The most frequent complaints were paraesthesia (43%), pain (35%), and fatigue (31%). The neurological examination was abnormal in 18% of children, autonomy was compromised in 14%, and symptoms of depression occurred in 34%. The factors associated with late-onset sequelae were correlated with severity during the initial phase (i.e. initial GBSDS >4, odds ratio 6.6, 95% CI 1.8-33; p = 0.009). The predictive factors of more severe late-onset conditions were initial severity (p = 0.002) and sex (female patients; p = 0.01). INTERPRETATION: Two-thirds of children with GBS had late-onset sequelae following an episode, often minor, but sometimes with continuing effects on their everyday lives. Particularly affected were those who had severe GBS during the acute phase and who lost the ability to walk. WHAT THIS PAPER ADDS: Two-thirds of children with Guillain-Barré syndrome (GBS) had persistent sequelae. Sequelae were often minor, but daily repercussions of them were sometimes serious. Sequelae were significantly associated with severe GBS during the acute phase.


Asunto(s)
Síndrome de Guillain-Barré , Humanos , Niño , Femenino , Síndrome de Guillain-Barré/complicaciones , Síndrome de Guillain-Barré/diagnóstico , Estudios Prospectivos , Progresión de la Enfermedad , Encuestas y Cuestionarios , Fatiga/complicaciones
6.
Eur J Neurol ; 30(9): 2828-2837, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37235686

RESUMEN

BACKGROUND: Classical infantile-onset Pompe disease (IOPD) is the most severe form of Pompe disease. Enzyme replacement therapy (ERT) has significantly increased survival but only a few studies have reported long-term outcomes. METHODS: We retrospectively analyzed the outcomes of classical IOPD patients diagnosed in France between 2004 and 2020. RESULTS: Sixty-four patients were identified. At diagnosis (median age 4 months) all patients had cardiomyopathy and most had severe hypotonia (57 of 62 patients, 92%). ERT was initiated in 50 (78%) patients and stopped later due to being ineffective in 10 (21%). Thirty-seven (58%) patients died during follow-up, including all untreated and discontinued ERT patients, and 13 additional patients. Mortality was higher during the first 3 years of life and after the age of 12 years. Persistence of cardiomyopathy during follow-up and/or the presence of heart failure were highly associated with an increased risk of death. In contrast, cross-reactive immunologic material (CRIM)-negative status (n = 16, 26%) was unrelated to increased mortality, presumably because immunomodulation protocols prevent the emergence of high antibody titers to ERT. Besides survival, decreased ERT efficacy appeared after the age of 6 years, with a progressive decline in motor and pulmonary functions for most survivors. CONCLUSIONS: This study reports the long-term follow-up of one of the largest cohorts of classical IOPD patients and demonstrates high long-term mortality and morbidity rates with a secondary decline in muscular and respiratory functions. This decreased efficacy seems to be multifactorial, highlighting the importance of developing new therapeutic approaches targeting various aspects of pathogenesis.


Asunto(s)
Cardiomiopatías , Enfermedad del Almacenamiento de Glucógeno Tipo II , Humanos , Niño , Lactante , Enfermedad del Almacenamiento de Glucógeno Tipo II/tratamiento farmacológico , Estudios de Seguimiento , Estudios Retrospectivos , Terapia de Reemplazo Enzimático/efectos adversos , Terapia de Reemplazo Enzimático/métodos
8.
Dev Med Child Neurol ; 65(2): 215-222, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-35765978

RESUMEN

AIM: To compare paediatric patients with cerebral sinovenous thrombosis (CSVT) with and without head/neck infection to improve management of the condition. METHOD: We conducted a bicentric retrospective study of consecutive children (neonates excluded) with radiologically confirmed CSVT, comparing children with a concurrent head/neck infection and children with other causes. RESULTS: A total of 84 consecutive patients (46 males and 38 females) with a median age of 4 years 6 months (range 3 months-17 years 5 months) were included. Associated head/neck infection was identified in 65.4% of cases and represented the main identified CSVT aetiology. Children in the head/neck infection group displayed a milder clinical presentation and less extensive CSVT. Median time to complete recanalization was significantly shorter in this group (89 days [interquartile range 35-101] vs 112.5 days [interquartile range 83-177], p = 0.005). These findings were even more pronounced in the subgroup of patients with otogenic infection and no neurological sign. INTERPRETATION: As CSVT in the setting of an otogenic infection and no neurological sign seems to represent a milder condition with a shorter course, these results suggest adapting current recommendations: consider earlier control imaging in paediatric otogenic CSVT, and shorter anticoagulant treatment if recanalization is obtained. WHAT THIS PAPER ADDS: Children with cerebral sinovenous thrombosis related to head/neck infections have a milder clinical presentation. They also have a shorter recanalization time, especially if there is otogenic infection without neurological symptoms.


Asunto(s)
Trombosis de los Senos Intracraneales , Trombosis de la Vena , Niño , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Estudios Retrospectivos , Factores de Riesgo , Trombosis de los Senos Intracraneales/complicaciones , Trombosis de los Senos Intracraneales/diagnóstico por imagen , Trombosis/complicaciones
9.
J Med Genet ; 60(6): 578-586, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36319078

RESUMEN

PURPOSE: In this study, we describe the phenotype and genotype of the largest cohort of patients with Joubert syndrome (JS) carrying pathogenic variants on one of the most frequent causative genes, CC2D2A. METHODS: We selected 53 patients with pathogenic variants on CC2D2A, compiled and analysed their clinical, neuroimaging and genetic information and compared it to previous literature. RESULTS: Developmental delay (motor and language) was nearly constant but patients had normal intellectual efficiency in 74% of cases (20/27 patients) and 68% followed mainstream schooling despite learning difficulties. Epilepsy was found in only 13% of cases. Only three patients had kidney cysts, only three had genuine retinal dystrophy and no subject had liver fibrosis or polydactyly. Brain MRIs showed typical signs of JS with rare additional features. Genotype-phenotype correlation findings demonstrate a homozygous truncating variant p.Arg950* linked to a more severe phenotype. CONCLUSION: This study contradicts previous literature stating an association between CC2D2A-related JS and ventriculomegaly. Our study implies that CC2D2A-related JS is linked to positive neurodevelopmental outcome and low rate of other organ defects except for homozygous pathogenic variant p.Arg950*. This information will help modulate patient follow-up and provide families with accurate genetic counselling.


Asunto(s)
Anomalías Múltiples , Anomalías del Ojo , Enfermedades Renales Quísticas , Humanos , Cerebelo/diagnóstico por imagen , Cerebelo/patología , Enfermedades Renales Quísticas/diagnóstico , Enfermedades Renales Quísticas/genética , Anomalías Múltiples/genética , Anomalías Múltiples/patología , Anomalías del Ojo/diagnóstico , Anomalías del Ojo/genética , Anomalías del Ojo/patología , Retina/diagnóstico por imagen , Retina/patología , Proteínas del Citoesqueleto
10.
Eur J Paediatr Neurol ; 40: 18-27, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35926472

RESUMEN

BACKGROUND: Dancing eye syndrome or opsoclonus-myoclonus syndrome (OMS) is a very rare disease (incidence <1/5,000,000 per year), which is more prevalent in young children. Although it is not usually a cause of mortality, the aftermaths are not rare. METHODS: We performed an observational retrospective review of children diagnosed with OMS in our neuropediatric department from 1996 to 2020, with the objective of assessing the prognostic value of initial clinical features. All medical data from diagnosis to last follow-up were reviewed. We defined unfavorable evolution of OMS as persistence or worsening of symptoms. Subsequently, based on a literature review, our results and experience, a diagnostic algorithm was developed. RESULTS: A total of 13 OMS patients were included: 61.5% were male (n = 8), median age at diagnosis was 18 months (IR = 76), median treatment delay was 14 days (IR = 146) and OMS score at onset was 8 (IR = 11). The most frequent etiologies were neuroblastoma-associated and idiopathic OMS (38.46%; n = 5) of the patients, followed by post-infectious OMS (n = 3). All the patients were treated with corticosteroids, five required a surgical intervention (neuroblastoma group), and three required adjunctive immune therapy (immunoglobulins, cyclophosphamide and/or rituximab). We detected neurodevelopmental disorders in 38.46% (n = 5) of the patients, mainly attention deficit (n = 4), and persistent sleep disturbances (n = 4). The median OMS score at the end of follow-up was 1 (IR = 3). An important diagnostic delay, OMS score of ≥10 and age >1 year at onset may correlate with a higher risk of aftermaths. We detected a better prognosis in the post-infectious OMS, with full recovery occurring in 2/3 of patients. CONCLUSIONS: Early clinical suspicion is key to guarantee maximum response of treatment.


Asunto(s)
Neuroblastoma , Síndrome de Opsoclonía-Mioclonía , Algoritmos , Niño , Preescolar , Diagnóstico Tardío/efectos adversos , Femenino , Humanos , Masculino , Neuroblastoma/complicaciones , Neuroblastoma/diagnóstico , Neuroblastoma/cirugía , Síndrome de Opsoclonía-Mioclonía/diagnóstico , Estudios Retrospectivos
11.
Neuropediatrics ; 53(3): 182-187, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35297028

RESUMEN

INTRODUCTION: Among the hereditary motor and sensory neuropathies (HMSN), demyelinating forms are the best characterized, with a clear predominance of CMT1A. The axonal and intermediate forms are less described. The aim of this study is to report the genetic diagnosis of Charcot-Marie-Tooth (CMT) according to the nerve conduction velocity (NCV) findings in a pediatric population. METHODS: We retrospectively described a population of HMSN children with a confirmed genetic diagnosis of demyelinated, intermediate, or axonal forms. We compared the results of the genetic analyses with those of motor NCV in median nerve according to whether they were below 25 m/s (demyelinating group); between 25 and 45 m/s (intermediate group), or above 45 m/s (axonal group). RESULTS: Among the 143 children with an HMSN, 107 had a genetic diagnosis of which 61 had an electromyogram. On NCV findings: seven (11%) pertain to the axonal group, 20 (32%) to the intermediate group, and 34 (55%) to the demyelinating group. When NCV was above 45 m/s, CMT2A was the predominant genetic diagnosis (70%) when NCV were below 25 m/s, CMT1A was the predominant genetic diagnosis (71%). Intermediate NCV findings group was the more heterogeneous with seven genetic CMT subgroups (60% CMT1A, CMT1B, CMT1X, CMT2A, CMT2N, CMT4G). CONCLUSION: Taking NCV values between 25 and 45 m/s to define an intermediate group of CMT in children leads to the inclusion of non-typically "intermediate", especially CMT1A. We emphasize the broad spectrum of NCV in CMT1A that justified the systematic search of PMP22 duplication/deletion screening before next generation sequencing panel.


Asunto(s)
Enfermedad de Charcot-Marie-Tooth , Neuropatía Hereditaria Motora y Sensorial , Enfermedad de Charcot-Marie-Tooth/diagnóstico , Enfermedad de Charcot-Marie-Tooth/genética , Niño , Pruebas Genéticas , Neuropatía Hereditaria Motora y Sensorial/diagnóstico , Neuropatía Hereditaria Motora y Sensorial/genética , Humanos , Conducción Nerviosa , Estudios Retrospectivos
12.
J Neurol ; 269(5): 2414-2429, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-34559299

RESUMEN

BACKGROUND: LAMA2-related muscular dystrophy (LAMA2-RD) encompasses a group of recessive muscular dystrophies caused by mutations in the LAMA2 gene, which codes for the alpha-2 chain of laminin-211 (merosin). Diagnosis is straightforward in the classic congenital presentation with no ambulation and complete merosin deficiency in muscle biopsy, but is far more difficult in milder ambulant individuals with partial merosin deficiency. OBJECTIVE: To investigate the diagnostic utility of muscle imaging in LAMA2-RD using whole-body magnetic resonance imaging (WBMRI). RESULTS: 27 patients (2-62 years, 21-80% with acquisition of walking ability and 6 never ambulant) were included in an international collaborative study. All carried two pathogenic mutations, mostly private missense changes. An intronic variant (c.909 + 7A > G) was identified in all the Chilean cases. Three patients (two ambulant) showed intellectual disability, epilepsy, and brain structural abnormalities. WBMRI T1w sequences or T2 fat-saturated images (Dixon) revealed abnormal muscle fat replacement predominantly in subscapularis, lumbar paraspinals, gluteus minimus and medius, posterior thigh (adductor magnus, biceps femoris, hamstrings) and soleus. This involvement pattern was consistent for both ambulant and non-ambulant patients. The degree of replacement was predominantly correlated to the disease duration, rather than to the onset or the clinical severity. A "COL6-like sandwich sign" was observed in several muscles in ambulant adults, but different involvement of subscapularis, gluteus minimus, and medius changes allowed distinguishing LAMA2-RD from collagenopathies. The thigh muscles seem to be the best ones to assess disease progression. CONCLUSION: WBMRI in LAMA2-RD shows a homogeneous pattern of brain and muscle imaging, representing a supportive diagnostic tool.


Asunto(s)
Imagen por Resonancia Magnética , Distrofias Musculares , Adulto , Humanos , Laminina/genética , Imagen por Resonancia Magnética/métodos , Músculo Esquelético/diagnóstico por imagen , Músculo Esquelético/patología , Distrofias Musculares/congénito , Distrofias Musculares/diagnóstico por imagen , Distrofias Musculares/genética , Imagen de Cuerpo Entero
13.
Int J Cardiovasc Imaging ; 38(1): 79-89, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34905152

RESUMEN

Prognosis of Duchenne muscular dystrophy (DMD) is related to cardiac dysfunction. Two dimensional-speckle tracking echocardiography (2D-STE) has recently emerged as a non-invasive functional biomarker for early detection of DMD-related cardiomyopathy. This study aimed to determine, in DMD children, the existence of left ventricle (LV) dyssynchrony using 2D-STE analysis. This prospective controlled study enrolled 25 boys with DMD (mean age 11.0 ± 3.5 years) with normal LV ejection fraction and 50 age-matched controls. Three measures were performed to assess LV mechanical dyssynchrony: the opposing-wall delays (longitudinal and radial analyses), the modified Yu index, and the time-to-peak delays of each segment. Feasibility and reproducibility of 2D-STE dyssynchrony were evaluated. All three mechanical dyssynchrony criteria were significantly higher in the DMD group than in healthy subjects: (1) opposing-wall delays in basal inferoseptal to basal anterolateral segments (61.4 ± 45.3 ms vs. 18.3 ± 50.4 ms, P < 0.001, respectively) and in mid inferoseptal to mid anterolateral segments (58.6 ± 35.3 ms vs. 42.4 ± 36.4 ms, P < 0.05, respectively), (2) modified Yu index (33.3 ± 10.1 ms vs. 28.5 ± 8.1 ms, P < 0.05, respectively), and (3) most of time-to-peak values, especially in basal and mid anterolateral segments. Feasibility was excellent and reliability was moderate to excellent, with ICC values ranging from 0.49 to 0.97. Detection of LV mechanical dyssynchrony using 2D-STE analysis is an easily and reproducible method in paediatric DMD. The existence of an early LV mechanical dyssynchrony visualized using 2D-STE analysis in children with DMD before the onset of cardiomyopathy represents a perspective for future paediatric drug trials in the DMD-related cardiomyopathy prevention.Clinical Trial Registration Clinicaltrials.gov NCT02418338. Post-hoc study, registered on April 16, 2015.


Asunto(s)
Distrofia Muscular de Duchenne , Disfunción Ventricular Izquierda , Adolescente , Niño , Ecocardiografía , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Masculino , Distrofia Muscular de Duchenne/complicaciones , Distrofia Muscular de Duchenne/diagnóstico por imagen , Valor Predictivo de las Pruebas , Estudios Prospectivos , Reproducibilidad de los Resultados , Disfunción Ventricular Izquierda/diagnóstico por imagen , Disfunción Ventricular Izquierda/etiología
14.
Int J Mol Sci ; 22(23)2021 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-34884796

RESUMEN

Duchenne muscular dystrophy (DMD) is characterized by progressive muscle wasting following repeated muscle damage and inadequate regeneration. Impaired myogenesis and differentiation play a major role in DMD as well as intracellular calcium (Ca2+) mishandling. Ca2+ release from the sarcoplasmic reticulum is mostly mediated by the type 1 ryanodine receptor (RYR1) that is required for skeletal muscle differentiation in animals. The study objective was to determine whether altered RYR1-mediated Ca2+ release contributes to myogenic differentiation impairment in DMD patients. The comparison of primary cultured myoblasts from six boys with DMD and five healthy controls highlighted delayed myoblast differentiation in DMD. Silencing RYR1 expression using specific si-RNA in a healthy control induced a similar delayed differentiation. In DMD myotubes, resting intracellular Ca2+ concentration was increased, but RYR1-mediated Ca2+ release was not changed compared with control myotubes. Incubation with the RYR-calstabin interaction stabilizer S107 decreased resting Ca2+ concentration in DMD myotubes to control values and improved calstabin1 binding to the RYR1 complex. S107 also improved myogenic differentiation in DMD. Furthermore, intracellular Ca2+ concentration was correlated with endomysial fibrosis, which is the only myopathologic parameter associated with poor motor outcome in patients with DMD. This suggested a potential relationship between RYR1 dysfunction and motor impairment. Our study highlights RYR1-mediated Ca2+ leakage in human DMD myotubes and its key role in myogenic differentiation impairment. RYR1 stabilization may be an interesting adjunctive therapeutic strategy in DMD.


Asunto(s)
Desarrollo de Músculos/fisiología , Músculo Esquelético/crecimiento & desarrollo , Distrofia Muscular de Duchenne/patología , Mioblastos/citología , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Calcio/metabolismo , Señalización del Calcio/fisiología , Diferenciación Celular/genética , Diferenciación Celular/fisiología , Células Cultivadas , Niño , Preescolar , Distrofina/metabolismo , Humanos , Masculino , Desarrollo de Músculos/genética , Fibras Musculares Esqueléticas/patología , Distrofia Muscular de Duchenne/metabolismo , Canal Liberador de Calcio Receptor de Rianodina/genética , Retículo Sarcoplasmático/metabolismo , Proteínas de Unión a Tacrolimus/metabolismo
16.
Genes (Basel) ; 12(8)2021 07 31.
Artículo en Inglés | MEDLINE | ID: mdl-34440373

RESUMEN

Diagnosis of myopathies is challenged by the high genetic heterogeneity and clinical overlap of the various etiologies. We previously reported a Next-Generation Sequencing strategy to identify genetic etiology in patients with undiagnosed Limb-Girdle Muscular Dystrophies, Congenital Myopathies, Congenital Muscular Dystrophies, Distal Myopathies, Myofibrillar Myopathies, and hyperCKemia or effort intolerance, using a large gene panel including genes classically associated with other entry diagnostic categories. In this study, we report the comprehensive clinical-biological strategy used to interpret NGS data in a cohort of 156 pediatric and adult patients, that included Copy Number Variants search, variants filtering and interpretation according to ACMG guidelines, segregation studies, deep phenotyping of patients and relatives, transcripts and protein studies, and multidisciplinary meetings. Genetic etiology was identified in 74 patients, a diagnostic yield (47.4%) similar to previous studies. We identified 18 patients (10%) with causative variants in different genes (ACTA1, RYR1, NEB, TTN, TRIP4, CACNA1S, FLNC, TNNT1, and PAPBN1) that resulted in milder and/or atypical phenotypes, with high intrafamilial variability in some cases. Mild phenotypes could mostly be explained by a less deleterious effect of variants on the protein. Detection of inter-individual variability and atypical phenotype-genotype associations is essential for precision medicine, patient care, and to progress in the understanding of the molecular mechanisms of myopathies.


Asunto(s)
Genotipo , Enfermedades Musculares/patología , Fenotipo , Adulto , Niño , Estudios de Cohortes , Femenino , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Masculino , Enfermedades Musculares/diagnóstico , Enfermedades Musculares/genética
17.
N Engl J Med ; 384(25): 2406-2417, 2021 06 24.
Artículo en Inglés | MEDLINE | ID: mdl-34161705

RESUMEN

BACKGROUND: Autophagy is the major intracellular degradation route in mammalian cells. Systemic ablation of core autophagy-related (ATG) genes in mice leads to embryonic or perinatal lethality, and conditional models show neurodegeneration. Impaired autophagy has been associated with a range of complex human diseases, yet congenital autophagy disorders are rare. METHODS: We performed a genetic, clinical, and neuroimaging analysis involving five families. Mechanistic investigations were conducted with the use of patient-derived fibroblasts, skeletal muscle-biopsy specimens, mouse embryonic fibroblasts, and yeast. RESULTS: We found deleterious, recessive variants in human ATG7, a core autophagy-related gene encoding a protein that is indispensable to classical degradative autophagy. Twelve patients from five families with distinct ATG7 variants had complex neurodevelopmental disorders with brain, muscle, and endocrine involvement. Patients had abnormalities of the cerebellum and corpus callosum and various degrees of facial dysmorphism. These patients have survived with impaired autophagic flux arising from a diminishment or absence of ATG7 protein. Although autophagic sequestration was markedly reduced, evidence of basal autophagy was readily identified in fibroblasts and skeletal muscle with loss of ATG7. Complementation of different model systems by deleterious ATG7 variants resulted in poor or absent autophagic function as compared with the reintroduction of wild-type ATG7. CONCLUSIONS: We identified several patients with a neurodevelopmental disorder who have survived with a severe loss or complete absence of ATG7, an essential effector enzyme for autophagy without a known functional paralogue. (Funded by the Wellcome Centre for Mitochondrial Research and others.).


Asunto(s)
Anomalías Múltiples/genética , Ataxia/genética , Proteína 7 Relacionada con la Autofagia/genética , Autofagia/genética , Discapacidades del Desarrollo/genética , Mutación Missense , Adolescente , Adulto , Autofagia/fisiología , Proteína 7 Relacionada con la Autofagia/fisiología , Células Cultivadas , Cerebelo/anomalías , Simulación por Computador , Cara/anomalías , Femenino , Fibroblastos , Genes Recesivos , Humanos , Lactante , Masculino , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Malformaciones del Sistema Nervioso/genética , Linaje , Fenotipo
18.
Eur Heart J ; 42(20): 1976-1984, 2021 05 21.
Artículo en Inglés | MEDLINE | ID: mdl-33748842

RESUMEN

AIMS: To estimate the effect of prophylactic angiotensin-converting enzyme inhibitors (ACEi) on survival in Duchenne muscular dystrophy (DMD). METHODS AND RESULTS: We analysed the data from the French multicentre DMD Heart Registry (ClinicalTrials.gov: NCT03443115). We estimated the association between the prophylactic prescription of ACEi and event-free survival in 668 patients aged 8 to 13 years, with normal left ventricular function, using (i) a Cox model with intervention as a time-dependent covariate, (ii) a propensity-based analysis comparing ACEi treatment vs. no treatment, and (iii) a set of sensitivity analyses. The study outcomes were overall survival and hospitalizations for heart failure (HF) or acute respiratory failure. Among the 668 patients included in the DMD Heart Registry, 576 (mean age 6.1 ± 2.8 years) were eligible for this study, of whom 390 were treated with ACEi prophylactically. Death occurred in 53 patients (13.5%) who were and 60 patients (32.3%) who were not treated prophylactically with ACEi, respectively. In a Cox model with intervention as a time-dependent variable, the hazard ratio (HR) associated with ACEi treatment was 0.49 [95% confidence interval (CI) 0.34-0.72] and 0.47 (95% CI 0.31-0.17) for overall mortality after adjustment for baseline variables. In the propensity-based analysis, 278 patients were included in the treatment group and 834 in the control group, with 18.5% and 30.4% 12-year estimated probability of death, respectively. ACEi were associated with a lower risk of death (HR 0.39; 95% CI 0.17-0.92) and hospitalization for HF (HR 0.16; 95% CI 0.04-0.62). All other sensitivity analyses yielded similar results. CONCLUSION: Prophylactic ACEi treatment in DMD was associated with a significantly higher overall survival and lower rates of hospitalization for HF.


Asunto(s)
Insuficiencia Cardíaca , Distrofia Muscular de Duchenne , Antagonistas de Receptores de Angiotensina/uso terapéutico , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Niño , Preescolar , Insuficiencia Cardíaca/tratamiento farmacológico , Insuficiencia Cardíaca/prevención & control , Humanos , Distrofia Muscular de Duchenne/tratamiento farmacológico , Sistema de Registros , Resultado del Tratamiento , Función Ventricular Izquierda
19.
Eur J Paediatr Neurol ; 31: 78-87, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33667896

RESUMEN

With the exception of infantile spinal muscular atrophy (SMA) and congenital myotonic dystrophy 1 (DM1), congenital myopathies and muscular dystrophies with neonatal respiratory distress pose diagnostic challenges. Next-generation sequencing (NGS) provides hope for the diagnosis of these rare diseases. We evaluated the efficiency of next-generation sequencing (NGS) in ventilated newborns with peripheral hypotonia. We compared the results of our previous study in a cohort of 19 patients analysed by Sanger sequencing from 2007 to 2012, with a diagnostic yield of 26% (5/19), and those of a new retrospective study in 28 patients from 2007 to 2018 diagnosed using MyoPanel, a neuromuscular disease panel, with a diagnostic yield of 43% (12/28 patients). Pathogenic variants were found in five genes: ACTA1 (n = 4 patients), RYR1 (n = 2), CACNA1S (n = 1), NEB (n = 3), and MTM1 (n = 2). Myopanel increased the diagnosis of congenital neuromuscular diseases, but more than half the patients remained undiagnosed. Whole exome sequencing did not seem to fully respond to this diagnostic limitation. Therefore, explorations with whole genome sequencing will be the next step.


Asunto(s)
Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Enfermedades Neuromusculares/diagnóstico , Síndrome de Dificultad Respiratoria del Recién Nacido/diagnóstico , Síndrome de Dificultad Respiratoria del Recién Nacido/etiología , Estudios de Cohortes , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Enfermedades Neuromusculares/genética , Estudios Retrospectivos
20.
J Child Neurol ; 36(8): 625-634, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33507832

RESUMEN

Attention span, which has been shown to have an impact on reading quality in many other conditions, is one of the main cognitive disorders of neurofibromatosis type 1 (NF1). The aim of this work is to observe the impact of attention on reading comprehension, in NF1 and non-NF1 children. A multicenter, cross-sectional study was conducted on 150 children (8-12 years old) with or without NF1 (75 NF1 vs 75 non-NF1; 72 female, 78 male), matched for age, sex, handedness, and reading level, thus forming a continuum from good to poor readers in both NF1 and non-NF1 groups. Children with intellectual deficiency or neurologic or psychiatric disorder were excluded. Attentional skills were assessed by combining a parent questionnaire (Child Behavior CheckList) and a performance-based assessment (Conner's Continuous Performance Test-Second Edition). Reading comprehension was assessed through a standardized reading comprehension test (ORLEC Lobrot). The performance-based attention scores were associated with text and sentence comprehension ability (P = .0235 and P = .0164, respectively), while indirect questionnaire attention scores were only associated with sentence comprehension (P = .0263). For both groups, the correlations between questionnaire and performance-based measures were low. We have shown that reading comprehension is greatly influenced by attention in NF1 and non-NF1, even if predictors of good reading comprehension also include IQ score and reading accuracy. Indirect observer-rated questionnaires and direct performance-based measures of attention do not assess the same variables, are linked to different components of reading skills, and are not interchangeable assessments of attention difficulties. Both assessments are complementary and must be used simultaneously, leading to recommendations that support multimodal assessment of attention.


Asunto(s)
Atención/fisiología , Trastornos del Conocimiento/diagnóstico , Comprensión/fisiología , Neurofibromatosis 1/fisiopatología , Pruebas Neuropsicológicas/estadística & datos numéricos , Lectura , Niño , Trastornos del Conocimiento/complicaciones , Trastornos del Conocimiento/fisiopatología , Estudios Transversales , Femenino , Humanos , Masculino , Neurofibromatosis 1/complicaciones
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