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BACKGROUND: Amyotrophic lateral sclerosis (ALS) leads to paralysis and death by progressive degeneration of motor neurons. Recently, specific gain-of-function mutations in SPTLC1 were identified in patients with juvenile form of ALS. SPTLC2 encodes the second catalytic subunit of the serine-palmitoyltransferase (SPT) complex. METHODS: We used the GENESIS platform to screen 700 ALS whole-genome and whole-exome data sets for variants in SPTLC2. The de-novo status was confirmed by Sanger sequencing. Sphingolipidomics was performed using liquid chromatography and high-resolution mass spectrometry. RESULTS: Two unrelated patients presented with early-onset progressive proximal and distal muscle weakness, oral fasciculations, and pyramidal signs. Both patients carried the novel de-novo SPTLC2 mutation, c.203T>G, p.Met68Arg. This variant lies within a single short transmembrane domain of SPTLC2, suggesting that the mutation renders the SPT complex irresponsive to regulation through ORMDL3. Confirming this hypothesis, ceramide and complex sphingolipid levels were significantly increased in patient plasma. Accordingly, excessive sphingolipid production was shown in mutant-expressing human embryonic kindney (HEK) cells. CONCLUSIONS: Specific gain-of-function mutations in both core subunits affect the homoeostatic control of SPT. SPTLC2 represents a new Mendelian ALS gene, highlighting a key role of dysregulated sphingolipid synthesis in the pathogenesis of juvenile ALS. Given the direct interaction of SPTLC1 and SPTLC2, this knowledge might open new therapeutic avenues for motor neuron diseases.
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Esclerosis Amiotrófica Lateral , Serina C-Palmitoiltransferasa , Humanos , Esclerosis Amiotrófica Lateral/genética , Ceramidas , Mutación con Ganancia de Función , Mutación/genética , Serina C-Palmitoiltransferasa/genética , Serina C-Palmitoiltransferasa/química , EsfingolípidosRESUMEN
INTRODUCTION/AIMS: There is limited information on the potential effects of repeated intrathecal antisense oligonucleotide drug delivery on cerebrospinal fluid (CSF) biochemical and blood cell profiles. This study aimed to examine longitudinal changes in the biochemical components (glucose, protein) and blood cell counts in the CSF of spinal muscular atrophy (SMA) patients treated with intrathecal nusinersen. METHODS: We collected and analyzed clinical and CSF parameters (cell count, protein, glucose, culture) of 50 individuals with SMA during nusinersen treatment (22 type 1, 17 type 2, and 11 type 3). RESULTS: The median protein concentration at baseline and during treatment was within the normal range but rose during treatment and was significantly above baseline at the time of the ninth intrathecal injection (p = 0.02, two-tailed Wilcoxon matched-pairs test, and p = 0.0015, Friedman test for repeated measures). Further analysis showed that the increase in CSF protein concentration was evident for SMA types 2 and 3 patients, but not for type 1. This observation was also demonstrated by a significant correlation between the SMN2 gene copy number and the increase in CSF protein concentration (Spearman rank correlation test). DISCUSSION: Our results demonstrate that a delayed increase in CSF protein concentration is expected during nusinersen treatment for SMA types 2 and 3. This might reflect the medication's effect and a possible therapeutic biochemical marker.
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Atrofia Muscular Espinal , Atrofias Musculares Espinales de la Infancia , Humanos , Atrofia Muscular Espinal/genética , Oligonucleótidos/uso terapéutico , Atrofias Musculares Espinales de la Infancia/tratamiento farmacológico , Inyecciones Espinales , GlucosaRESUMEN
Pompe's disease occurs due to an autosomal recessive trait resulting from numerous distinctive mutations in the GAA gene. It manifests as a broad spectrum of clinical phenotypes with progressive weakness that impairs motor and respiratory functions being common for all its forms. Cardiac hypertrophy is a prominent feature of its classic infantile form. To date, the pathogenic variant c.2015G > A (p.Arg672Gln) in exon 14 of the GAA gene has been described in 10 children of different ethnic groups, with variable phenotypic presentations. This work describes three children from two unrelated families of Arab ethnicity who presented with infantile-onset Pompe's disease as a result of a c.2015G > A (p.Arg672Gln) mutation. The clinical course of the children we report was more severe than previous reports. This further emphasizes the lack of a strict genotype-phenotype correlation in regard to the unique c.2015G > A (p.R672Q) mutation that causes Pompe's disease. This information contributes to the knowledge of the phenotypic expression of the specific mutation c.2015G > A (p.Arg672Gln) that causes Pompe's disease.
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Enfermedad del Almacenamiento de Glucógeno Tipo II , alfa-Glucosidasas , Progresión de la Enfermedad , Estudios de Asociación Genética , Enfermedad del Almacenamiento de Glucógeno Tipo II/genética , Enfermedad del Almacenamiento de Glucógeno Tipo II/metabolismo , Humanos , Mutación , alfa-Glucosidasas/genética , alfa-Glucosidasas/metabolismoRESUMEN
BACKGROUND: Headache is a common complaint in children at a pediatric emergency department (PED). The primary objective of this analysis is to describe the outcome of patients presenting with headache to the PED and discharged with neurology follow up. The secondary objective is to describe the diagnostic evaluation children with headache underwent in the PED and to evaluate headache characteristics which are more likely associated with serious, life-threatening conditions. METHODS: A retrospective chart review of children who were discharged from the PED after evaluation for headache, with a scheduled urgent neurology outpatient clinic follow up at the same institution, over a 3.5-year period. RESULTS: During the study period, we identified 300 children whose admitting diagnosis was headache and they were discharged from the PED with a scheduled follow up. None of these patients had papilledema on fundoscopy performed by an ophthalmologist during the PED visit. Following neurology outpatient clinic visit, 62 (21%) were referred to perform brain magnetic resonance imaging. None of the patients had a diagnosis of brain tumor or any anatomic abnormality that could increase intracranial pressure. CONCLUSIONS: No immediate life-threatening cases presented to the follow up neurology clinic for evaluation. A scheduled urgent neurology outpatient clinic follow up in any child with headache who is discharged from the PED, offers a safety net, even when the physical examination including fundoscopy is normal.
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Atención Ambulatoria/métodos , Servicio de Urgencia en Hospital , Cefalea/terapia , Adolescente , Niño , Preescolar , Servicios Médicos de Urgencia , Femenino , Cefalea/diagnóstico por imagen , Humanos , Lactante , Imagen por Resonancia Magnética , Masculino , Pacientes Ambulatorios , Dimensión del Dolor , Papiledema/diagnóstico , Papiledema/diagnóstico por imagen , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
INTRODUCTION: Preseptal (periorbital) and orbital cellulitis are potentially catastrophic infections near the eye. Preseptal cellulitis is far more common, and although classically reported to be associated with dacrocystitis, sinusitis/upper respiratory infection, trauma/surgery, or infection from contiguous areas, it can also be associated with insect bites. The objective of this study was to determine the prevalence of insect bite-associated preseptal cellulitis and to compare clinical findings and outcomes of these patients with those having other causes for the condition. METHODS: Retrospective chart review of children with a final discharge diagnosis of periorbital cellulitis from January 2009 to December 2014 at a tertiary care children' hospital. RESULTS: 213 children were diagnosed with preseptal cellulitis during the 5-year study period, of whom 60 (28%) were associated with insect bites. Patients in the noninsect bite group more commonly had fever at presentation (P < 0.001), with increased white blood cell and C reactive protein values (both P < 0.001). No patient with insect bite-associated preseptal cellulitis presented with fever, and none underwent radiographic testing or computerized tomography; their mean age was also lower (P < 0.001) and length of stay was significantly shorter. CONCLUSIONS: This study suggests that children with preseptal cellulitis associated with insect bites could be candidates for oral antibiotic therapy with outpatient follow-up by.
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Antibacterianos/uso terapéutico , Mordeduras y Picaduras de Insectos/complicaciones , Celulitis Orbitaria/tratamiento farmacológico , Administración Oral , Preescolar , Femenino , Hospitales Pediátricos/estadística & datos numéricos , Humanos , Lactante , Masculino , Celulitis Orbitaria/epidemiología , Celulitis Orbitaria/etiología , Prevalencia , Estudios Retrospectivos , Centros de Atención Terciaria/estadística & datos numéricos , Resultado del TratamientoRESUMEN
INTRODUCTION: Several works have reported on the antiepileptic impact of cannabis-based preparations in patients with treatment-resistant epilepsy (TRE). However, current formulations suffer from low bioavailability and side effects. PTL-101, an oral formulation containing highly purified cannabidiol (CBD) embedded in seamless gelatin matrix beadlets was designed to enhance bioavailability and maintain a constant gastrointestinal transit time. METHODS: This phase II, prospective study was open to pediatric patients with TRE on stable antiepileptic drugs' (AEDs) doses, who experienced ≥4 seizures within four weeks of enrolment and with a history of ≥4 AEDs failing to provide seizure control. Following a 4-week observation period, patients began a 2-week dose-titration phase (up to ≤25mg/kg or 450mg, the lower of the two), followed by a 10-week maintenance treatment period. Caregivers recorded seizure frequency, type, and severity and ranked their global impressions after 7 and 12weeks of treatment. Responders were those showing a ≥50% reduction from baseline monthly seizure frequency. Safety assessments monitored vital signs, adverse effects, physical and neurological exams, and laboratory tests. RESULTS: Sixteen patients (age: 9.1±3.4) enrolled in the study; 11 completed the full treatment program. The average maintenance dose was 13.6±4.2mg/kg. Patient adherence to treatment regimens was 96.3±9.9%. By the end of the treatment period, 81.9% and 73.4±24.6% (p<0.05) reductions from baseline median seizure count and monthly seizure frequency, respectively, were recorded. Responders' rate was 56%; two patients became fully seizure-free. By study end, 8 (73%) caregivers reported an improved/very much improved condition, and 9 (82%) reported reduced/very much reduced seizure severity. Most commonly reported treatment-related adverse effects were sleep disturbance/insomnia, (4 (25.0%) patients), followed by somnolence, increased seizure frequency, and restlessness (3 patients each (18.8%)). None were serious or severe, and all resolved. CONCLUSIONS: PTL-101 was safe and tolerable for use and demonstrated a potent seizure-reducing effect among pediatric patients with TRE.
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Anticonvulsivantes/administración & dosificación , Cannabidiol/administración & dosificación , Epilepsia Refractaria/diagnóstico , Epilepsia Refractaria/tratamiento farmacológico , Administración Oral , Adolescente , Anticonvulsivantes/efectos adversos , Cannabidiol/efectos adversos , Niño , Preescolar , Composición de Medicamentos , Epilepsia Refractaria/epidemiología , Quimioterapia Combinada , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/diagnóstico , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/epidemiología , Femenino , Humanos , Masculino , Estudios Prospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: Acute disseminated encephalomyelitis (ADEM) is an uncommon, treatable, primarily pediatric, immune-mediated disease. Diagnosis of ADEM requires two essential elements: typical clinical presentation and magnetic resonance imaging (MRI) findings. The aim of this study was to evaluate how clinical findings in the initial emergency department (ED) presentation influenced the timing of MRI. METHODS: A retrospective chart review was conducted of children diagnosed with ADEM, over a 12-year period, in a tertiary care pediatric center. Clinical presentation at ED admission was recorded and patients who underwent an MRI as part of their ED evaluation (early MRI) with those who had MRI performed during ward hospitalization (late MRI) were compared. RESULTS: 30 patients were diagnosed with ADEM during the study period. Encephalopathy and polyfocal neurological signs were described in 80% and 50% of patients ED charts, respectively. Seven patients underwent early MRI and polyfocal neurological signs were more common in this group (pâ¯=â¯0.006). Fever was more common in the late MRI group (pâ¯=â¯0.02). Following diagnosis, all patients were treated with immune-modulation therapy, improved clinically, and were discharged. CONCLUSION: 20% of ADEM patients were not encephalopathic at ED presentation. Polyfocal neurological signs and absence of fever at ED presentation were related to earlier MRI utilization and thus earlier diagnosis and treatment. Familiarity with the ADEM constellation of signs, and a high index of suspicion, may help the ED clinician in early diagnosis and treatment of this rare disease.
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Encéfalo/diagnóstico por imagen , Encefalomielitis Aguda Diseminada/diagnóstico , Imagen por Resonancia Magnética , Examen Neurológico , Adolescente , Niño , Preescolar , Toma de Decisiones , Servicio de Urgencia en Hospital , Encefalomielitis Aguda Diseminada/tratamiento farmacológico , Encefalomielitis Aguda Diseminada/fisiopatología , Femenino , Fiebre/etiología , Humanos , Inmunoglobulinas/administración & dosificación , Lactante , Masculino , Prednisolona/administración & dosificación , Prednisolona/análogos & derivados , Estudios Retrospectivos , Convulsiones/etiología , Factores de TiempoRESUMEN
Objective To assess the role of placental cultures in cases of preterm premature rupture of membranes (PPROM) complicated by chorioamnionitis and to determine the effect of positive cultures on short-term neonatal outcomes. Design A retrospective single-center study. The medical records of all women with PPROM between January 1, 2011, and December 31, 2015, were reviewed. Cases were divided into placental culture positive (group A) and placental culture negative (group B) groups. Maternal and pregnancy characteristics as well as short-term neonatal outcomes were compared between groups. Results During the 5-year study period, 61 cases of clinical chorioamnionitis complicating PPROM were diagnosed: 25 cases were culture positive (group A) and 36 were culture negative (group B). Neonatal outcome measures, including Apgar score at 5 minutes (p = 0.028; odds ratio [OR]: 5.27; confidence interval [CI]: 1.19-23.34), respiratory distress syndrome (p = 0.026; OR: 4.11; CI: 1.18-14.25), and neonatal infection (p < 0.0001; OR: 11.59; CI: 3.37-39.87) were significantly more common in group A newborns, regardless of gestational age at delivery as was the composite neonatal outcome (p = 0.017; OR: 7.35: CI: 1.42-37.79). Placental isolates were primarily Streptococci and Escherichia coli. Conclusion Placental cultures may be an essential predictor of neonatal morbidity in PPROM and may contribute to the modification of neonatal treatment.
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Infecciones Bacterianas/diagnóstico , Corioamnionitis/microbiología , Rotura Prematura de Membranas Fetales/microbiología , Placenta/microbiología , Complicaciones Infecciosas del Embarazo/microbiología , Adulto , Antibacterianos/administración & dosificación , Puntaje de Apgar , Infecciones Bacterianas/tratamiento farmacológico , Corioamnionitis/tratamiento farmacológico , Escherichia coli/aislamiento & purificación , Femenino , Rotura Prematura de Membranas Fetales/tratamiento farmacológico , Edad Gestacional , Humanos , Recién Nacido , Israel , Modelos Logísticos , Masculino , Análisis Multivariante , Embarazo , Complicaciones Infecciosas del Embarazo/tratamiento farmacológico , Resultado del Embarazo , Síndrome de Dificultad Respiratoria del Recién Nacido/etiología , Estudios Retrospectivos , Streptococcus/aislamiento & purificaciónRESUMEN
BACKGROUND: The cerebrospinal (CSF) constitutes a specific immune micro-environment to the central nervous system, thus it may contain specific biomarkers involved in the pathogenesis of multiple sclerosis (MS). OBJECTIVES: We aimed to study a large array of inflammatory CSF biomarkers in patients with suspected MS to recognize potential early diagnostic markers. METHODS: CSF samples were obtained from 115 patients who presented with neurological symptomatology suggestive of MS as follows: clinically isolated syndrome (CIS) = 49, relapsing-remitting multiple sclerosis (RRMS) = 29, and other neurologic disorders (OND) = 37. Protein expression profiles of 30 inflammatory biomarkers were measured by multiplex Luminex bead assay and further analyzed by group comparison statistics, correlation studies and receiver-operating characteristic (ROC) analysis. RESULTS: Interleukin-12 subunit p40 (IL12p40) demonstrated a significant differential expression pattern between the groups (CIS vs OND: p = 1.17*10(-7); RRMS vs OND: p = 4.98*10(-5)), with higher levels in CIS and RRMS patients. ROC analysis demonstrated excellent diagnostic performance of IL12p40 for discrimination between CIS and OND patients (area under the curve = 0.87 (95% CI 0.78-0.93), p = 0.0001). No associations were found with disease activity or severity measures. CONCLUSIONS: An increased IL12p40 level characterizes the CSF of MS patients and appears to be helpful in identifying CIS and OND patients early in the process of clinical diagnostic assessment.
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Biomarcadores/líquido cefalorraquídeo , Enfermedades Desmielinizantes/líquido cefalorraquídeo , Subunidad p40 de la Interleucina-12/líquido cefalorraquídeo , Adolescente , Adulto , Anciano , Área Bajo la Curva , Enfermedades del Sistema Nervioso Central/líquido cefalorraquídeo , Enfermedades del Sistema Nervioso Central/diagnóstico , Enfermedades Desmielinizantes/diagnóstico , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Masculino , Persona de Mediana Edad , Esclerosis Múltiple Recurrente-Remitente/líquido cefalorraquídeo , Curva ROC , Adulto JovenRESUMEN
Background: LAMA2-related dystrophies (LAMA2-RDs) represent one of the most common forms of congenital muscular dystrophy and have historically been classified into two subtypes: complete or partial deficiency of laminin-211 (merosin). Patients with LAMA2-RD with the typical congenital phenotype manifest severe muscle weakness, delayed motor milestones, joint contractures, failure to thrive, and progressive respiratory insufficiency. Objective: While a comprehensive prospective natural history study has been performed in LAMA2-RD patients over 5 years of age, the early natural history of patients with LAMA2-RD 5 years and younger has not been comprehensively characterized. Methods: We extracted retrospective data for patients with LAMA2-RD ages birth through 5 years via the Congenital Muscle Disease International Registry (CMDIR). We analyzed the data using a phenotypic classification based on maximal motor milestones to divide patients into two phenotypic groups: "Sit" for those patients who attained that ability to remain seated and "Walk" for those patients who attained the ability to walk independently by 3.5 years of age. Results: Sixty patients with LAMA2-RD from 10 countries fulfilled the inclusion criteria. Twenty-four patients had initiated non-invasive ventilation by age 5 years. Hospitalizations during the first years of life were often related to respiratory insufficiency. Feeding/nutritional difficulties and orthopedic issues were commonly reported. Significant elevations of creatine kinase (CK) observed during the neonatal period declined rapidly within the first few months of life. Conclusions: This is the largest international retrospective early natural history study of LAMA2-RD to date, contributing essential data for understanding early clinical findings in LAMA2-RD which, along with the data being collected in international, prospective early natural history studies, will help to establish clinical trial readiness. Our proposed nomenclature of LAMA2-RD1 for patients who attain the ability to sit (remain seated) and LAMA2-RD2 for patients who attain the ability to walk independently is aimed at further improving LAMA2-RD classification.
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Biallelic pathogenic variants in the gene encoding nebulin (NEB) are a known cause of congenital myopathy. We present two individuals with congenital myopathy and compound heterozygous variants (NM_001271208.2: c.2079C>A; p.(Cys693Ter) and c.21522+3A>G ) in NEB. Transcriptomic sequencing on patient muscle revealed that the extended splice variant c.21522+3A>G causes exon 144 skipping. Nebulin isoforms containing exon 144 are known to be mutually exclusive with isoforms containing exon 143, and these isoforms are differentially expressed during development and in adult skeletal muscles. Patients MRIs were compared to the known pattern of relative abundance of these two isoforms in muscle. We propose that the pattern of muscle involvement in these patients better fits the distribution of exon 144-containing isoforms in muscle than with previously published MRI findings in NEB-related disease due to other variants. To our knowledge this is the first report hypothesizing disease pathogenesis through the alteration of isoform distributions in muscle.
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Biallelic pathogenic variants in the gene encoding nebulin (NEB) are a known cause of congenital myopathy. We present two brothers with congenital myopathy and compound heterozygous variants (NC_000002.12:g.151692086G>T; NM_001271208.2: c.2079C>A; p.(Cys693Ter) and NC_000002.12:g.151533439T>C; NM_001271208.2:c.21522+3A>G) in NEB. Transcriptomic sequencing on affected individual muscles revealed that the extended splice variant c.21522+3A>G causes exon 144 skipping. Nebulin isoforms containing exon 144 are known to be mutually exclusive with isoforms containing exon 143, and these isoforms are differentially expressed during development and in adult skeletal muscles. Affected individuals' MRI patterns of muscle involvement were compared with the known pattern of relative abundance of these two isoforms in muscle. We propose that the pattern of muscle involvement in these affected individuals better fits the distribution of exon 144-containing isoforms in muscle than with previously published MRI findings in NEB-related disease due to other variants. Our report introduces disease pathogenesis and manifestation as a result of alteration of isoform distributions in muscle.
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Cytoplasmic and nuclear iron-sulfur (Fe-S) enzymes that are essential for genome maintenance and replication depend on the cytoplasmic Fe-S assembly (CIA) machinery for cluster acquisition. The core of the CIA machinery consists of a complex of CIAO1, MMS19 and FAM96B. The physiological consequences of loss of function in the components of the CIA pathway have thus far remained uncharacterized. Our study revealed that patients with biallelic loss of function in CIAO1 developed proximal and axial muscle weakness, fluctuating creatine kinase elevation, and respiratory insufficiency. In addition, they presented with CNS symptoms including learning difficulties and neurobehavioral comorbidities, along with iron deposition in deep brain nuclei, mild normocytic to macrocytic anemia, and gastrointestinal symptoms. Mutational analysis revealed reduced stability of the variants compared with WT CIAO1. Functional assays demonstrated failure of the variants identified in patients to recruit Fe-S recipient proteins, resulting in compromised activities of DNA helicases, polymerases, and repair enzymes that rely on the CIA complex to acquire their Fe-S cofactors. Lentivirus-mediated restoration of CIAO1 expression reversed all patient-derived cellular abnormalities. Our study identifies CIAO1 as a human disease gene and provides insights into the broader implications of the cytosolic Fe-S assembly pathway in human health and disease.
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Proteínas Hierro-Azufre , Humanos , Proteínas Hierro-Azufre/genética , Proteínas Hierro-Azufre/metabolismo , Masculino , Femenino , Enfermedades Neuromusculares/genética , Enfermedades Neuromusculares/enzimología , Enfermedades Neuromusculares/metabolismo , Enfermedades Neuromusculares/patología , Niño , Núcleo Celular/metabolismo , Núcleo Celular/enzimología , Núcleo Celular/genética , Citoplasma/metabolismo , Citoplasma/enzimología , MetalochaperonasRESUMEN
Background: Neurogenetic disorders caused by pathogenic variants in four genes encoding non-erythrocytic spectrins ( SPTAN1, SPTBN1, SPTBN2, SPTBN4) range from peripheral and central nervous system involvement to complex syndromic presentations. Heterozygous pathogenic variants in SPTAN1 are exemplary for this diversity with phenotypes spanning almost the entire spectrum. Methods: Through international collaboration we identified 14 families with genetically unsolved distal weakness and unreported heterozygous SPTAN1 loss-of-function variants including frameshift, nonsense and splice-acceptor variants. Clinical data, electrophysiology, muscle CT or MRI and muscle biopsy findings were collected and standardized. SPTAN1 protein, mRNA expression analysis and cDNA sequencing was performed on muscle tissue from two patients. Results: All 20 patients presented with early childhood onset distal weakness. The severity varied both within families and between different families. Foot abnormalities ranged from hammer toes and pes cavus to distal arthrogryposis. Electrophysiology showed mixed myogenic and neurogenic features. Muscle MRI or CT in 10 patients showed fatty infiltration of the distal lower limb anterior compartment and/or selective involvement of the extensor hallucis longus muscle. Muscle biopsy revealed myopathic changes with mild dystrophic and chronic neurogenic changes in 7 patients. Finally, we provide proof for nonsense mediated decay in tissues derived from two patients. Conclusions: We provide evidence for the association of SPTAN1 loss-of-function variants with childhood onset distal myopathy in 14 families. This finding extends the phenotypic spectrum of SPTAN1 loss-of-function variants ranging from intellectual disability to distal weakness with a predominant myogenic cause. KEY MESSAGES: SPTAN1 loss-of-function variants, including frameshift, nonsense and splice site variants cause a novel childhood onset distal weakness syndrome with primarily skeletal muscle involvement. Hereditary motor neuropathies and distal myopathic disorders present a well-known diagnostic challenge as they demonstrate substantial clinical and genetic overlap. The emergence of SPTAN1 loss-of-function variants serves as a noteworthy example, highlighting a growing convergence in the spectrum of genotypes linked to both hereditary motor neuropathies and distal myopathies.
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Collagen VI-related dystrophies (COL6-RDs) manifest with a spectrum of clinical phenotypes, ranging from Ullrich congenital muscular dystrophy (UCMD), presenting with prominent congenital symptoms and characterised by progressive muscle weakness, joint contractures and respiratory insufficiency, to Bethlem muscular dystrophy, with milder symptoms typically recognised later and at times resembling a limb girdle muscular dystrophy, and intermediate phenotypes falling between UCMD and Bethlem muscular dystrophy. Despite clinical and immunohistochemical features highly suggestive of COL6-RD, some patients had remained without an identified causative variant in COL6A1, COL6A2 or COL6A3. With combined muscle RNA-sequencing and whole-genome sequencing we uncovered a recurrent, de novo deep intronic variant in intron 11 of COL6A1 (c.930+189C>T) that leads to a dominantly acting in-frame pseudoexon insertion. We subsequently identified and have characterised an international cohort of forty-four patients with this COL6A1 intron 11 causative variant, one of the most common recurrent causative variants in the collagen VI genes. Patients manifest a consistently severe phenotype characterised by a paucity of early symptoms followed by an accelerated progression to a severe form of UCMD, except for one patient with somatic mosaicism for this COL6A1 intron 11 variant who manifests a milder phenotype consistent with Bethlem muscular dystrophy. Characterisation of this individual provides a robust validation for the development of our pseudoexon skipping therapy. We have previously shown that splice-modulating antisense oligomers applied in vitro effectively decreased the abundance of the mutant pseudoexon-containing COL6A1 transcripts to levels comparable to the in vivo scenario of the somatic mosaicism shown here, indicating that this therapeutic approach carries significant translational promise for ameliorating the severe form of UCMD caused by this common recurrent COL6A1 causative variant to a Bethlem muscular dystrophy phenotype.
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Troponin I (TnI) regulates thin filament activation and muscle contraction. Two isoforms, TnI-fast (TNNI2) and TnI-slow (TNNI1), are predominantly expressed in fast- and slow-twitch myofibers, respectively. TNNI2 variants are a rare cause of arthrogryposis, whereas TNNI1 variants have not been conclusively established to cause skeletal myopathy. We identified recessive loss-of-function TNNI1 variants as well as dominant gain-of-function TNNI1 variants as a cause of muscle disease, each with distinct physiological consequences and disease mechanisms. We identified three families with biallelic TNNI1 variants (F1: p.R14H/c.190-9G>A, F2 and F3: homozygous p.R14C), resulting in loss of function, manifesting with early-onset progressive muscle weakness and rod formation on histology. We also identified two families with a dominantly acting heterozygous TNNI1 variant (F4: p.R174Q and F5: p.K176del), resulting in gain of function, manifesting with muscle cramping, myalgias, and rod formation in F5. In zebrafish, TnI proteins with either of the missense variants (p.R14H; p.R174Q) incorporated into thin filaments. Molecular dynamics simulations suggested that the loss-of-function p.R14H variant decouples TnI from TnC, which was supported by functional studies showing a reduced force response of sarcomeres to submaximal [Ca2+] in patient myofibers. This contractile deficit could be reversed by a slow skeletal muscle troponin activator. In contrast, patient myofibers with the gain-of-function p.R174Q variant showed an increased force to submaximal [Ca2+], which was reversed by the small-molecule drug mavacamten. Our findings demonstrated that TNNI1 variants can cause muscle disease with variant-specific pathomechanisms, manifesting as either a hypo- or a hypercontractile phenotype, suggesting rational therapeutic strategies for each mechanism.
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Enfermedades Musculares , Sarcómeros , Animales , Humanos , Calcio/metabolismo , Contracción Muscular , Músculo Esquelético/metabolismo , Enfermedades Musculares/genética , Sarcómeros/metabolismo , Troponina I/genética , Troponina I/metabolismo , Pez Cebra/metabolismoRESUMEN
Cytoplasmic and nuclear iron-sulfur enzymes that are essential for genome maintenance and replication depend on the cytoplasmic iron-sulfur assembly (CIA) machinery for cluster acquisition. Here we report that patients with biallelic loss of function in CIAO1 , a key CIA component, develop proximal and axial muscle weakness, fluctuating creatine kinase elevation and respiratory insufficiency. In addition, they present with CNS symptoms including learning difficulties and neurobehavioral comorbidities, along with iron deposition in deep brain nuclei, macrocytic anemia and gastrointestinal symptoms. Mutational analysis and functional assays revealed reduced stability of the variants compared to wild-type CIAO1. Loss of CIAO1 impaired DNA helicases, polymerases and repair enzymes which rely on the CIA complex to acquire their Fe-S cofactors, with lentiviral restoration reversing all patient-derived cellular abnormalities. Our study identifies CIAO1 as a novel human disease gene and provides insights into the broader implications of the iron-sulfur assembly pathway in human health and disease.
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The clinical applicability and yield of brain magnetic resonance imaging (MRI) in the setting of an inpatient pediatric department has not been investigated. The authors performed a retrospective chart review of nontraumatic/nonneurosurgical children who underwent brain MRI during their hospitalization in a general pediatric department over a 5-year period. Of the 331 children who underwent brain MRI, 148 (45%) had abnormal findings. High-risk headaches and focal seizures were significantly correlated with findings on brain MRI. Diagnostic and therapeutic yields were most significant in acute demyelinating events, acute cerebrovascular disorders, high-risk headaches when supported by neurologic and ophthalmologic findings, focal seizures with evidence of multifocal epileptic activity on an electroencephalogram and ophthalmic complaints when accompanied by cranial nerve palsy and optic nerve impairment. Since the contributions of a brain MRI in hospitalized children is pivotal in specific clinical situations, a judicious decision-making process should be done before its scheduling, in order to optimize clinical care.
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Encefalopatías/diagnóstico por imagen , Pacientes Internos , Imagen por Resonancia Magnética/métodos , Neuroimagen/métodos , Adolescente , Encéfalo/diagnóstico por imagen , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Estudios RetrospectivosRESUMEN
BACKGROUND: Hyponatremia during labor and delivery may result in severe maternal and neonatal sequelae. Our aim was to describe the direct effect of hyponatremia in labor on pregnancy outcome. METHODS: A case series of parturients diagnosed with hyponatremia during labor and their neonates. Clinical presentation, laboratory workup, and maternal and neonatal outcomes are presented. RESULTS: Four parturients and their corresponding six neonates were diagnosed with hyponatremia. Of these, two cases were caused by water intoxication and two were preeclampsia induced. While two were identified due to maternal or neonatal symptoms, two were diagnosed by routine laboratory testing. In all cases, low maternal sodium resulted in similarly low neonatal sodium. Neonatal symptoms included respiratory distress syndrome (RDS), lethargy, and jaundice. CONCLUSION: Psychogenic drinking during labor and preeclampsia may predispose to maternal hyponatremia, resulting in neonatal hyponatremia. Early recognition and treatment can prevent further maternal deterioration and adverse neonatal sequelae.
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Hiponatremia/etiología , Enfermedades del Recién Nacido/etiología , Preeclampsia/fisiopatología , Intoxicación por Agua/complicaciones , Adulto , Anestesia Epidural/efectos adversos , Femenino , Humanos , Hiponatremia/sangre , Hiponatremia/terapia , Síndrome de Secreción Inadecuada de ADH/complicaciones , Recién Nacido , Enfermedades del Recién Nacido/sangre , Enfermedades del Recién Nacido/terapia , Trabajo de Parto/sangre , Trabajo de Parto/fisiología , Masculino , Persona de Mediana Edad , Embarazo , Resultado del EmbarazoRESUMEN
OBJECTIVES: Long-term storage of human milk (HM) requires freezing at low temperatures, the consequences of which upon macronutrients are unclear. The conflicting results of the few studies on freezing-induced changes on HM macronutrients led to different storage recommendations. We examined differences in macronutrients content of HM after long-term storage at -20°C compared with -80°C. MATERIALS AND METHODS: Mature HM samples from 25 mothers of term and preterm infants were collected. Each sample was divided into six aliquots for storage at -20°C and -80°C for 4, 12, and 24 weeks. After thawing and homogenization, energy and macronutrients content were measured using an HM infrared spectroscopy analyzer. RESULTS: A total of 150 HM samples were available for analysis. Thirteen samples were removed due to calibration errors. The final analysis was performed on 137 samples with validated results. Fat and energy content were consistently higher in the -80°C samples compared with the paired -20°C samples at each time point (p < 0.05). Comparison of the differences in macronutrients content over time (4 versus 24 weeks) revealed a significant loss of fat (0.3 g/100 mL [7.9%], p = 0.001) and energy (2.3 kcal/100 mL [3.3%], p = 0.03) in the -20°C group. Fat and protein were also significantly decreased over time in the -80°C group (by 0.14 g/100 mL [3%], p = 0.009, and 0.06 g/100 mL [6.4%], p = 0.02, respectively). CONCLUSIONS: Long-term storage of HM at -80°C is associated with better fat and energy preservation compared with storage at -20°C. These results may help construct evidence-based recommendations and guidelines for optimal HM storage.