The deposition of proteins in the form of amyloid fibrils is closely associated with several serious diseases. The events that trigger the conversion from soluble functional proteins into insoluble ...amyloid are not fully understood. Many proteins that are not associated with disease can form amyloid with similar structural characteristics as the disease-associated fibrils, which highlights the potential risk of cross-seeding of disease amyloid by amyloid-like structures encountered in our surrounding. Of particular interest are common food proteins that can be transformed into amyloid under conditions similar to cooking. We here investigate cross-seeding of amyloid-β (Aβ), a peptide known to form amyloid during the development of Alzheimer's disease, by 16 types of amyloid fibrils derived from food proteins or peptides. Kinetic studies using thioflavin T fluorescence as output show that none of the investigated protein fibrils accelerates the aggregation of Aβ. In at least two cases (hen egg lysozyme and oat protein isolate) we observe retardation of the aggregation, which appears to originate from interactions between the food protein seeds and Aβ in aggregated form. The results support the view that food-derived amyloid is not a risk factor for development of Aβ pathology and Alzheimer's disease.
The major ampullate Spidroin 1 (MaSp1) is the main protein of the dragline spider silk. The C-terminal (CT) domain of MaSp1 is crucial for the self-assembly into fibers but the details of how it ...contributes to the fiber formation remain unsolved. Here we exploit the fact that the CT domain can form silk-like fibers by itself to gain knowledge about this transition. Structural investigations of fibers from recombinantly produced CT domain from E. australis MaSp1 reveal an α-helix to β-sheet transition upon fiber formation and highlight the helix N
4 segment as most likely to initiate the structural conversion. This prediction is corroborated by the finding that a peptide corresponding to helix N
4 has the ability of pH-induced conversion into β-sheets and self-assembly into nanofibrils. Our results provide structural information about the CT domain in fiber form and clues about its role in triggering the structural conversion of spidroins during fiber assembly.
New treatments in spinal muscular atrophy Gowda, Vasantha Lakshmi; Fernandez-Garcia, Miguel A.; Jungbluth, Heinz ...
Archives of disease in childhood,
07/2023, Letnik:
108, Številka:
7
Journal Article
Recenzirano
Spinal muscular atrophy (SMA) is a severe neurodegenerative condition due to recessive mutations in the SMN1 gene resulting in insufficiency of survival motor neuron (SMN) protein. Lack of SMN ...protein results in irreversible degeneration of lower motor neurons and consequential muscle atrophy and weakness. SMN2, a SMN1 homologue, produces low levels of functional SMN protein with the potential to partially compensate SMN1 loss. Several compounds have been shown to successfully restore SMN protein production in motor neurons, either by enhancing SMN2 gene function or by direct replacement of the SMN1 gene. Clinical trials of these compounds have demonstrated the potential to substantially alter the natural history of SMA and have led to their implementation into clinical practice. To date, 3 novel drugs, nusinersen, onasemnogene aberparvovec and risdiplam, have received marketing authorisation for SMA treatment by several authorities including Food and Drug Administration and European Medicines Agency. While implementing these drugs into daily clinical practice, clinicians face a number of new challenges, including identifying the most advantageous treatment for any individual, optimisation of outcomes and management of a modified SMA phenotype. Considering that treatment initiation at the pre-symptomatic or paucisymptomatic stage appears to be associated with better outcomes, health services need to support early diagnosis for this now treatable condition. This review aims to give an overview of the current therapeutic landscape of SMA, to provide an understanding of current practice of SMA management and to help increase awareness of the imminent need for urgent early diagnosis at the pre-symptomatic stage.
X-linked recessive mutations in the dystrophin gene are one of the most common causes of inherited neuromuscular disorders in humans. Duchenne muscular dystrophy, the most common phenotype, and ...Becker muscular dystrophy are often recognizable by certain clinical features; however, less frequent presentations require a higher degree of suspicion. In this article, we describe a series of 6 children (4 boys, 2 girls) referred to a tertiary pediatric neuromuscular clinic for isolated elevated creatine kinase levels (range: 720-7000 IU/L) identified on initial assessment for otherwise unexplained transaminase elevations (
= 2), a social communication disorder (
= 3), and exertional myalgia and/or rhabdomyolysis (
= 1). There was no preceding family history of neuromuscular disease. One boy had an additional history of severe cerebral palsy and cyclical vomiting, and 1 girl had a history of maternal hepatitis C. There was no significant weakness at presentation, and the majority remained stable over a prolonged period of follow-up (age range at last follow-up: 9-16 years). All 6 children were found to carry dystrophin gene mutations resulting in milder phenotypes. This series highlights that dystrophinopathies may not uncommonly present with features distinct from the classic Duchenne muscular dystrophy and Becker muscular dystrophy phenotypes in both boys and girls. Pediatricians should be aware of such atypical presentations to initiate a timely and adequate diagnostic process. Establishing the correct genetic diagnosis of a dystrophinopathy is important to allow appropriate genetic counseling, to implement relevant surveillance and management strategies, and to avoid unnecessary investigations in search of an incorrect alternative diagnosis.
The present research work has focused on combined experimental and theoretical studies of one of the biologically important pyrazole-4-carboxylic acid derivatives, viz. 5-methyl-1-phenyl-1
H
...-pyrazole-4-carboxylic acid (C
11
H
10
N
2
O
2
). The starting material 5-methyl-1-phenyl-1
H
-4-pyrazolecarboxylate (
1
) was obtained by the cyclocondensation of ethyl acetoacetate,
N
,
N
-dimethylformamide dimethyl acetal (DMF-DMA), and phenylhydrazine, which upon basic hydrolysis yielded the corresponding acid (
2
). The target compound (
2
) was characterized by
1
H and
13
C NMR (solution in DMSO), Fourier transform infrared (FT-IR) spectroscopy, thermo gravimetric analysis, and by single-crystal X-ray diffraction technique. The single crystals of compound (
2
) were obtained at room temperature by slow evaporation of ethanol as solvent and crystallized in the space group
P2
1
/
n
of monoclinic system. The experimental FT-IR and
1
H and
13
C NMR chemical shifts have been compared to those calculated by means of density functional theory (DFT) at the B3LYP/TZ2P level of theory. The continuum-like screening model was used for geometry optimization of a single molecule and for subsequent calculations of NMR shielding constants in solution (DMSO). Finally, the HOMO–LUMO energy levels were also constructed to study the electronic transition within the molecule by time-dependent TD-DFT method.
ObjectiveTo describe age and time at key stages in the Duchenne muscular dystrophy (DMD) prediagnosis pathway at selected centres to identify opportunities for service improvement.DesignA multicentre ...retrospective national audit.SettingNine tertiary neuromuscular centres across the UK and Ireland. A prior single-centre UK audit of 20 patients with no DMD family history provided benchmark criteria.PatientsPatients with a definitive diagnosis of DMD documented within 3 years prior to December 2018 (n=122).Main outcome measuresMean age (months) at four key stages in the DMD diagnostic pathway and mean time (months) of presentational and diagnostic delay, and time from first reported symptoms to definitive diagnosis. Type of symptoms was also recorded.ResultsOverall, mean age at definitive diagnosis, age at first engagement with healthcare professional (HCP) and age at first reported symptoms were 53.9±29.7, 49.9±28.9 and 36.4±26.8 months, respectively. The presentational delay and time to diagnosis were 21.1 (±21.1) and 4.6 (±7.9) months, respectively. The mean time from first reported symptoms to definitive diagnosis was 24.2±20.9. The percentages of patients with motor and/or non-motor symptoms recorded were 88% (n=106/121) and 47% (n=57/121), respectively.ConclusionsMajority of data mirrored the benchmark audit. However, while the time to diagnosis was shorter, a presentational delay was observed. Failure to recognise early symptoms of DMD could be a contributing factor and represents an unmet need in the diagnosis pathway. Methods determining how to improve this need to be explored.
Nusinersen has shown significant functional motor benefit in the milder types of spinal muscular atrophy (SMA). Less is known on the respiratory outcomes in patients with nusinersen-treated SMA. The ...aim of this study was to describe changes in respiratory function in pediatric patients with SMA type 2 and 3 on regular treatment with nusinersen within the iSMAc international cohort and to compare their trajectory with the natural history (NH) data published by the consortium in 2020.Background and ObjectivesNusinersen has shown significant functional motor benefit in the milder types of spinal muscular atrophy (SMA). Less is known on the respiratory outcomes in patients with nusinersen-treated SMA. The aim of this study was to describe changes in respiratory function in pediatric patients with SMA type 2 and 3 on regular treatment with nusinersen within the iSMAc international cohort and to compare their trajectory with the natural history (NH) data published by the consortium in 2020.This is a 5-year retrospective observational study of pediatric SMA type 2 and nonambulant type 3 (age ≤18 years) treated with nusinersen. The primary objective was to compare the slopes of decline in forced vital capacity % predicted (FVC% pred.), FVC, and age when FVC dropped below 60% between the treated patients and a control group from the natural history cohort. Data on peak cough flow and the use of noninvasive ventilation (NIV) and cough assist were collected.MethodsThis is a 5-year retrospective observational study of pediatric SMA type 2 and nonambulant type 3 (age ≤18 years) treated with nusinersen. The primary objective was to compare the slopes of decline in forced vital capacity % predicted (FVC% pred.), FVC, and age when FVC dropped below 60% between the treated patients and a control group from the natural history cohort. Data on peak cough flow and the use of noninvasive ventilation (NIV) and cough assist were collected.Data were available for 69 treated patients, 53 were SMA type 2 and 16 type 3. The mean (SD) age at first injection was 8.5 (3.2) and 9.7 (3.7) years, respectively. The median (interquartile range) treatment duration was 1 (0.7; 1.9) and 1.2 (0.9; 1.9) years, respectively. At the time of the first nusinersen injection, 24 of 52 (46%) patients with SMA type 2 and 2 of 16 (13%) patients with SMA type 3 were on NIV. Forty-three of 53 (81%) and 4 of 16 (25%) patients used cough device. FVC% pred. in treated patients with SMA type 2 declined annually by 2.3% vs 3.9% in NH (p = 0.08) and in treated patients with type 3 by 2.6% vs 3.4% NH (p = 0.59). Patients treated reached FVC <60% later than untreated (12.1 vs 10 years, p = 0.05). A higher percentage of treated vs untreated patients maintained FVC% pred. equal/above their baseline after 12 (65% vs 36%) and 24 (50% vs 24%) months, respectively. NIV use among treated did not significantly change throughout 1-year follow-up.ResultsData were available for 69 treated patients, 53 were SMA type 2 and 16 type 3. The mean (SD) age at first injection was 8.5 (3.2) and 9.7 (3.7) years, respectively. The median (interquartile range) treatment duration was 1 (0.7; 1.9) and 1.2 (0.9; 1.9) years, respectively. At the time of the first nusinersen injection, 24 of 52 (46%) patients with SMA type 2 and 2 of 16 (13%) patients with SMA type 3 were on NIV. Forty-three of 53 (81%) and 4 of 16 (25%) patients used cough device. FVC% pred. in treated patients with SMA type 2 declined annually by 2.3% vs 3.9% in NH (p = 0.08) and in treated patients with type 3 by 2.6% vs 3.4% NH (p = 0.59). Patients treated reached FVC <60% later than untreated (12.1 vs 10 years, p = 0.05). A higher percentage of treated vs untreated patients maintained FVC% pred. equal/above their baseline after 12 (65% vs 36%) and 24 (50% vs 24%) months, respectively. NIV use among treated did not significantly change throughout 1-year follow-up.This study included the largest real-world cohort of pediatric patients with milder SMA types. The results suggest a positive role of nusinersen in delaying the respiratory decline in patients treated longer than 1 year when compared with natural history. Larger cohorts and longer observation are planned.DiscussionThis study included the largest real-world cohort of pediatric patients with milder SMA types. The results suggest a positive role of nusinersen in delaying the respiratory decline in patients treated longer than 1 year when compared with natural history. Larger cohorts and longer observation are planned.This study provided Class III evidence that nusinersen slows progression for patients with SMA types 2 and 3 compared with a natural history cohort.Classification of EvidenceThis study provided Class III evidence that nusinersen slows progression for patients with SMA types 2 and 3 compared with a natural history cohort.
Abstract Acute flaccid weakness may be the first presentation of acute transverse myelitis (ATM), an immune-mediated central nervous system disorder or may be the first presentation of anterior horn ...cell syndrome or peripheral nervous system disease. . We describe two previously healthy female infants who presented with acute flaccid paralysis and encephalopathy. Neuroimaging revealed central cord signal changes in both cases and surprisingly electrophysiological studies performed revealed a generalized axonal motor neuropathy as well. The etiology, preferred treatment and overall outcome of this overlap syndrome are discussed in this article.
ObjectiveAromatic L-amino acid decarboxylase deficiency (AADCd) is a rare neurometabolic disorder resulting from variants in the dopa decarboxylase (DDC) gene. Diagnosis of AADCd is often delayed ...because of variable clinical presentation. Patients are frequently misdiagnosed with more common conditions, such as cerebral palsy (CP) owing to a lack of AADCd awareness. REVEAL-CP is a prospective, multicentre, multinational, interventional, non-registrational study designed to investigate the prevalence of AADCd in patients presenting with symptoms of CP and to characterise genotypes associated with high 3-O-methyldopa (3-OMD) levels in dried blood spot samples. Following the study, UK paediatric neurologist investigators completed a survey on learning opportunities to improve the early identification of patients with AADCd who may be eligible for treatment.MethodsThe REVEAL-CP study screened patient records. After exclusion of patients with genetic and/or CSF neurotransmitter analysis, 49 UK patients were identified as being suitable for 3-OMD testing. Following the study, UK investigators completed a survey developed in collaboration with PharmaGenesis London, a third-party agency, including questions requiring yes/no, Likert scale (strongly agree; somewhat agree; neither agree nor disagree; somewhat disagree; strongly disagree; don’t know) and/or qualitative responses. Consensus was reached if the majority of investigator respondents somewhat or strongly agreed to individual questions.ResultsSix investigators completed the survey and reached consensus on the following recommendations to improve AADCd patient identification in the UK: adoption of a more centralised record system between NHS trusts, particularly between community and secondary paediatric practices; implementing genetic testing as the primary diagnostic tool for patients with CP-like symptoms of unknown aetiology; increasing awareness among clinicians of the differential diagnosis of neurotransmitter disorders in patients with CP-like symptoms; and earlier use of 3-OMD testing in the diagnostic workup of patients presenting with unexplained movement disorders or CP-like symptoms, alongside testing for serum prolactin and urinary organic acids including vanillactate, through the establishment of a nationally accredited 3-OMD service.ConclusionsA greater number of patients with CP-like symptoms of unknown aetiology could be screened for AADCd, taking into consideration the investigators’ suggestions. For rare diseases like AADCd, the provision of additional resources will be key for targeted patient screening. Given the recent EMA and MHRA marketing authorisation approvals for the first licensed gene therapy for AADCd, these improved efforts for early diagnosis could prove critical to the timely and effective management of patients with AADCd.ReferencesRizzi S, et al. Behav Neurol 2022;2022:2210555.Opladen T, et al. Mol Genet Metab Rep 2016;9:61–6.Burlina A, et al. Mol Genet Metab 2021;133:56–62.Chien YH, et al. Mol Genet Metab 2016;118:259–63.
PDF
