Cell-mediated cytotoxicity within CSF and brain parenchyma in spinal muscular atrophy unaltered by nusinersen treatment.

5q-associated spinal muscular atrophy (SMA) is a motoneuron disease caused by mutations in the survival motor neuron 1 (SMN1) gene. Adaptive immunity may contribute to SMA as described in other motoneuron diseases, yet mechanisms remain elusive. Nusinersen, an antisense treatment, enhances SMN2 expression, benefiting SMA patients. Here we have longitudinally investigated SMA and nusinersen effects on local immune responses in the cerebrospinal fluid (CSF) - a surrogate of central nervous system parenchyma. Single-cell transcriptomics (SMA: N = 9 versus Control: N = 9) reveal NK cell and CD8+ T cell expansions in untreated SMA CSF, exhibiting activation and degranulation markers. Spatial transcriptomics coupled with multiplex immunohistochemistry elucidate cytotoxicity near chromatolytic motoneurons (N = 4). Post-nusinersen treatment, CSF shows unaltered protein/transcriptional profiles. These findings underscore cytotoxicity's role in SMA pathogenesis and propose it as a therapeutic target. Our study illuminates cell-mediated cytotoxicity as shared features across motoneuron diseases, suggesting broader implications.

Fatigue in Spinal Muscular Atrophy: a fundamental open issue.

Hereditary proximal 5q Spinal Muscular Atrophy (SMA) is a severe neuromuscular disorder with onset mainly in infancy or childhood. The underlying pathogenic mechanism is the loss of alpha motor neurons in the anterior horns of spine, due to deficiency of the survival motor neuron (SMN) protein as a consequence of the deletion of the SMN1 gene. Clinically, SMA is characterized by progressive loss of muscle strength and motor function ranging from the extremely severe, the neonatal onset type 1, to the mild type 4 arising in the adult life. All the clinical variants share the same molecular defect, the difference being driven mainly by the copy number of SMN2 gene, a centromeric gene nearly identical to SMN1 with a unique C to T transition in Exon 7 that results in exclusion of Exon 7 during post-transcriptional processing. In all the types of SMA the clinical picture is characterized by hypotonia, weakness and areflexia. Clinical severity can vary a lot between the four main recognized types of SMA. As for the most of patients affected by different neuromuscular disorders, also in SMA fatigability is a major complaint as it is frequently reported in common daily activities and negatively impacts on the overall quality of life. The increasing awareness of fatigability as an important dimension of impairment in Neuromuscular Disorders and particularly in SMA, is making it both a relevant subject of study and identifies it as a fundamental therapeutic target. In this review, we aimed to overview the current literature articles concerning this problem, in order to highlight what is known and what deserves further research.

Dysregulation of innate immune signaling in animal models of spinal muscular atrophy.

BACKGROUND: Spinal muscular atrophy (SMA) is a devastating neuromuscular disease caused by hypomorphic loss of function in the survival motor neuron (SMN) protein. SMA presents across a broad spectrum of disease severity. Unfortunately, genetic models of intermediate SMA have been difficult to generate in vertebrates and are thus unable to address key aspects of disease etiology. To address these issues, we developed a Drosophila model system that recapitulates the full range of SMA severity, allowing studies of pre-onset biology as well as late-stage disease processes. RESULTS: Here, we carried out transcriptomic and proteomic profiling of mild and intermediate Drosophila models of SMA to elucidate molecules and pathways that contribute to the disease. Using this approach, we elaborated a role for the SMN complex in the regulation of innate immune signaling. We find that mutation or tissue-specific depletion of SMN induces hyperactivation of the immune deficiency (IMD) and Toll pathways, leading to overexpression of antimicrobial peptides (AMPs) and ectopic formation of melanotic masses in the absence of an external challenge. Furthermore, the knockdown of downstream targets of these signaling pathways reduced melanotic mass formation caused by SMN loss. Importantly, we identify SMN as a negative regulator of a ubiquitylation complex that includes Traf6, Bendless, and Diap2 and plays a pivotal role in several signaling networks. CONCLUSIONS: In alignment with recent research on other neurodegenerative diseases, these findings suggest that hyperactivation of innate immunity contributes to SMA pathology. This work not only provides compelling evidence that hyperactive innate immune signaling is a primary effect of SMN depletion, but it also suggests that the SMN complex plays a regulatory role in this process in vivo. In summary, immune dysfunction in SMA is a consequence of reduced SMN levels and is driven by cellular and molecular mechanisms that are conserved between insects and mammals.

Alteration of LARGE1 abundance in patients and a mouse model of 5q-associated spinal muscular atrophy.

Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by recessive pathogenic variants affecting the survival of motor neuron (SMN1) gene (localized on 5q). In consequence, cells lack expression of the corresponding protein. This pathophysiological condition is clinically associated with motor neuron (MN) degeneration leading to severe muscular atrophy. Additionally, vulnerability of other cellular populations and tissues including skeletal muscle has been demonstrated. Although the therapeutic options for SMA have considerably changed, treatment responses may differ thus underlining the persistent need for validated biomarkers. To address this need and to identify novel marker proteins for SMA, we performed unbiased proteomic profiling on cerebrospinal fluid derived (CSF) from genetically proven SMA type 1-3 cases and afterwards performed ELISA studies on CSF and serum samples to validate the potential of a novel biomarker candidates in both body fluids. To further decipher the pathophysiological impact of this biomarker, immunofluorescence studies were carried out on spinal cord and skeletal muscle derived from a 5q-SMA mouse model. Proteomics revealed increase of LARGE1 in CSF derived from adult patients showing a clinical response upon treatment with nusinersen. Moreover, LARGE1 levels were validated in CSF samples of further SMA patients (type 1-3) by ELISA. These studies also unveiled a distinguishment between groups in improvement of motor skills: adult patients do present with lowered level per se at baseline visit while no elevation upon treatment in the pediatric cohort can be observed. ELISA-based studies of serum samples showed no changes in the pediatric cohort but unraveled elevated level in adult patients responding to future intervention with nusinersen, while non-responders did not show a significant increase. Additional immunofluorescence studies of LARGE1 in MN and skeletal muscle of a SMA type 3 mouse model revealed an increase of LARGE1 during disease progression. Our combined data unraveled LARGE1 as a protein dysregulated in serum and CSF of SMA-patients (and in MN and skeletal muscle of SMA mice) holding the potential to serve as a disease marker for SMA and enabling to differentiate between patients responding and non-responding to therapy with nusinersen.

Repeated AAV9 Titer Determination in a Presymptomatic SMA Patient with Three SMN2 Gene Copies - A Case Report.

Adeno-associated viruses (AAV) are well-suited to serve as gene transfer vectors. Onasemnogene abeparvovec uses AAV9 as virus vector. Previous exposure to wild-type AAVs or placental transfer of maternal AAV antibodies, however, can trigger an immune response to the vector virus which may limit the therapeutic effectiveness of gene transfer and impact safety. We present the case of a female patient with spinal muscular atrophy (SMA) and three survival motor neuron 2 (SMN2) gene copies. The infant had elevated titers of AAV9 antibodies at diagnosis at 9 days of age. Being presymptomatic at diagnosis, it was decided to retest the patient's AAV9 antibody titer at two-weekly intervals. Six weeks after initial diagnosis, a titer of 1:12.5 allowed treatment with onasemnogene abeparvovec. The presented case demonstrates that, provided the number of SMN2 gene copies and the absence of symptoms allow, onasemnogene abeparvovec therapy is feasible in patients with initially exclusionary AAV9 antibody titers of >1:50.

Improved gene therapy for spinal muscular atrophy in mice using codon-optimized hSMN1 transgene and hSMN1 gene-derived promotor.

Physiological regulation of transgene expression is a major challenge in gene therapy. Onasemnogene abeparvovec (Zolgensma®) is an approved adeno-associated virus (AAV) vector gene therapy for infants with spinal muscular atrophy (SMA), however, adverse events have been observed in both animals and patients following treatment. The construct contains a native human survival motor neuron 1 (hSMN1) transgene driven by a strong, cytomegalovirus enhancer/chicken ß-actin (CMVen/CB) promoter providing high, ubiquitous tissue expression of SMN. We developed a second-generation AAV9 gene therapy expressing a codon-optimized hSMN1 transgene driven by a promoter derived from the native hSMN1 gene. This vector restored SMN expression close to physiological levels in the central nervous system and major systemic organs of a severe SMA mouse model. In a head-to-head comparison between the second-generation vector and a benchmark vector, identical in design to onasemnogene abeparvovec, the 2nd-generation vector showed better safety and improved efficacy in SMA mouse model.

Long term peripheral AAV9-SMN gene therapy promotes survival in a mouse model of spinal muscular atrophy.

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by motor neuron loss and skeletal muscle atrophy. SMA is caused by the loss of the SMN1 gene and low SMN protein levels. Current SMA therapies work by increasing SMN protein in the body. Although SMA is regarded as a motor neuron disorder, growing evidence shows that several peripheral organs contribute to SMA pathology. A gene therapy treatment, onasemnogene abeparvovec, is being explored in clinical trials via both systemic and central nervous system (CNS) specific delivery, but the ideal route of delivery as well as the long-term effectiveness is unclear. To investigate the impact of gene therapy long term, we assessed SMA mice at 6 months after treatment of either intravenous (IV) or intracerebroventricular (ICV) delivery of scAAV9-cba-SMN. Interestingly, we observed that SMN protein levels were restored in the peripheral tissues but not in the spinal cord at 6 months of age. However, ICV injections provided better motor neuron and motor function protection than IV injection, while IV-injected mice demonstrated better protection of neuromuscular junctions and muscle fiber size. Surprisingly, both delivery routes resulted in an equal rescue on survival, weight, and liver and pancreatic defects. These results demonstrate that continued peripheral AAV9-SMN gene therapy is beneficial for disease improvement even in the absence of SMN restoration in the spinal cord.

Optimization of base editors for the functional correction of SMN2 as a treatment for spinal muscular atrophy.

Spinal muscular atrophy (SMA) is caused by mutations in SMN1. SMN2 is a paralogous gene with a C•G-to-T•A transition in exon 7, which causes this exon to be skipped in most SMN2 transcripts, and results in low levels of the protein survival motor neuron (SMN). Here we show, in fibroblasts derived from patients with SMA and in a mouse model of SMA that, irrespective of the mutations in SMN1, adenosine base editors can be optimized to target the SMN2 exon-7 mutation or nearby regulatory elements to restore the normal expression of SMN. After optimizing and testing more than 100 guide RNAs and base editors, and leveraging Cas9 variants with high editing fidelity that are tolerant of different protospacer-adjacent motifs, we achieved the reversion of the exon-7 mutation via an A•T-to-G•C edit in up to 99% of fibroblasts, with concomitant increases in the levels of the SMN2 exon-7 transcript and of SMN. Targeting the SMN2 exon-7 mutation via base editing or other CRISPR-based methods may provide long-lasting outcomes to patients with SMA.

Gene therapy in spinal muscular atrophy.

Infantile SMA is a neuromuscular disease caused by the motor neuron degeneration, depending on the age of appearance of clinical signs and the evolution of the disease, three types of decreasing severity have been defined. SMA is caused by mutations or deletions of the SMN1 gene and disease. Various therapies aimed at increasing SMN protein levels have been developed. Gene therapy is part of the therapeutic arsenal now available for the treatment of SMA under certain conditions. It uses the scAAV9 vector carrying a functional copy of SMN1 to restore SMN protein expression at the cellular level. Because the adeno-associated virus genome is maintained as it is an episome, a single intravenous administration is sufficient to producing a long-lasting therapeutic effect. The effectiveness of gene replacement therapy in patients with SMA has been demonstrated in various studies. It is now clear that treatment as early as possible provides better clinical results. However, this treatment must be carried out in a suitable medical environment, with close monitoring initially due to potentially serious side effects. In France, this treatment has been available since 2019. A national committee of experts involved in the treatment of pediatric SMA patients has established that pediatric patients with SMA decide on the indications for disease-modifying therapies (DMT) in children. The French Spinal Muscular Atrophy Registry (SMA France Registry) was established in January 2020. The registry includes all patients with genetically confirmed SMN1-related SMA. All patients treated with GT are systematically included in the registry. As of July 21, 2023: 72 patients with SMA have been treated with GT in France since June 2019. The arrival of new treatments reveals new clinical phenotypes of SMA which constitute a new management challenge. Treatment as early as possible is also a very important factor for a favorable outcome and calls for presymptomatic screening. However, the arrival of these new treatments, extremely expensive raises other socio-economic questions. © 2023 Published by Elsevier Masson SAS on behalf of French Society of Pediatrics.

Carrier Screening Programs for Cystic Fibrosis, Fragile X Syndrome, Hemoglobinopathies and Thalassemia, and Spinal Muscular Atrophy: A Health Technology Assessment.

Background: We conducted a health technology assessment to evaluate the safety, effectiveness, and cost-effectiveness of carrier screening programs for cystic fibrosis (CF), fragile X syndrome (FXS), hemoglobinopathies and thalassemia, and spinal muscular atrophy (SMA) in people who are considering a pregnancy or who are pregnant. We also evaluated the budget impact of publicly funding carrier screening programs, and patient preferences and values. Methods: We performed a systematic literature search of the clinical evidence. We assessed the risk of bias of each included study using the Cochrane Risk of Bias tool and the Risk of Bias Assessment tool for Non-randomized Studies (RoBANS), and the quality of the body of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We performed a systematic economic literature search and conducted cost-effectiveness analyses comparing preconception or prenatal carrier screening programs to no screening. We considered four carrier screening strategies: 1) universal screening with standard panels; 2) universal screening with a hypothetical expanded panel; 3) risk-based screening with standard panels; and 4) risk-based screening with a hypothetical expanded panel. We also estimated the 5-year budget impact of publicly funding preconception or prenatal carrier screening programs for the given conditions in Ontario. To contextualize the potential value of carrier screening, we spoke with 22 people who had sought out carrier screening. Results: We included 107 studies in the clinical evidence review. Carrier screening for CF, hemoglobinopathies and thalassemia, FXS, and SMA likely results in the identification of couples with an increased chance of having an affected pregnancy (GRADE: Moderate). Screening likely impacts reproductive decision-making (GRADE: Moderate) and may result in lower anxiety among pregnant people, although the evidence is uncertain (GRADE: Very low).We included 21 studies in the economic evidence review, but none of the study findings were directly applicable to the Ontario context. Our cost-effectiveness analyses showed that in the short term, preconception or prenatal carrier screening programs identified more at-risk pregnancies (i.e., couples that tested positive) and provided more reproductive choice options compared with no screening, but were associated with higher costs. While all screening strategies had similar values for health outcomes, when comparing all strategies together, universal screening with standard panels was the most cost-effective strategy for both preconception and prenatal periods. The incremental cost-effectiveness ratios (ICERs) of universal screening with standard panels compared with no screening in the preconception period were $29,106 per additional at-risk pregnancy detected and $367,731 per affected birth averted; the corresponding ICERs in the prenatal period were about $29,759 per additional at-risk pregnancy detected and $431,807 per affected birth averted.We estimated that publicly funding a universal carrier screening program in the preconception period over the next 5 years would require between $208 million and $491 million. Publicly funding a risk-based screening program in the preconception period over the next 5 years would require between $1.3 million and $2.7 million. Publicly funding a universal carrier screening program in the prenatal period over the next 5 years would require between $128 million and $305 million. Publicly funding a risk-based screening program in the prenatal period over the next 5 years would require between $0.8 million and $1.7 million. Accounting for treatment costs of the screened health conditions resulted in a decrease in the budget impact of universally provided carrier screening programs or cost savings for risk-based programs.Participants value the perceived potential positive impact of carrier screening programs such as medical benefits from early detection and treatment, information for reproductive decision-making, and the social benefit of awareness and preparation. There was a strong preference expressed for thorough, timely, unbiased information to allow for informed reproductive decision-making. Conclusions: Carrier screening for CF, FXS, hemoglobinopathies and thalassemia, and SMA is effective at identifying at-risk couples, and test results may impact preconception and reproductive decision-making.The cost-effectiveness and budget impact of carrier screening programs are uncertain for Ontario. Over the short term, carrier screening programs are associated with higher costs, and also higher chances of detecting at-risk pregnancies compared with no screening. The 5-year budget impact of publicly funding universal carrier screening programs is larger than that of risk-based programs. However, accounting for treatment costs of the screened health conditions results in a decrease in the total additional costs for universal carrier screening programs or in cost savings for risk-based programs.The people we spoke with who had sought out carrier screening valued the potential medical benefits of early detection and treatment, particularly the support and preparation for having a child with a potential genetic condition.

NRF2 has a splicing regulatory function involving the survival of motor neuron (SMN) in non-small cell lung cancer.

The nuclear factor erythroid 2-like 2 (NFE2L2; NRF2) signaling pathway is frequently deregulated in human cancers. The critical functions of NRF2, other than its transcriptional activation, in cancers remain largely unknown. Here, we uncovered a previously unrecognized role of NRF2 in the regulation of RNA splicing. Global splicing analysis revealed that NRF2 knockdown in non-small cell lung cancer (NSCLC) A549 cells altered 839 alternative splicing (AS) events in 485 genes. Mechanistic studies demonstrated that NRF2 transcriptionally regulated SMN mRNA expression by binding to two antioxidant response elements in the SMN1 promoter. Post-transcriptionally, NRF2 was physically associated with the SMN protein. The Neh2 domain of NRF2, as well as the YG box and the region encoded by exon 7 of SMN, were required for their interaction. NRF2 formed a complex with SMN and Gemin2 in nuclear gems and Cajal bodies. Furthermore, the NRF2-SMN interaction regulated RNA splicing by expressing SMN in NRF2-knockout HeLa cells, reverting some of the altered RNA splicing. Moreover, SMN overexpression was significantly associated with alterations in the NRF2 pathway in patients with lung squamous cell carcinoma from The Cancer Genome Atlas. Taken together, our findings suggest a novel therapeutic strategy for cancers involving an aberrant NRF2 pathway.

Expanding the phenotype of DYNC1H1-associated diseases with a rare variant resulting in spinal muscular atrophy with lower extremity predominance (SMA-LED) and upper motor neuron signs.

BACKGROUND: Spinal muscular atrophy with lower extremity predominance (SMA-LED) is an autosomal dominant disorder. Since SMA-LED affects lower motor neurons, the disease is characterized by weakness and atrophy of lower limb muscles. We present a familial case series of SMA-LED with upper motor neuron signs associated with a rare variant in DYNC1H1. CASE: The index case was referred to Pediatric Neurology at the age of two and half years, due to delayed mobility. The child was diagnosed with congenital vertical talus at birth, which was managed with serial bilateral casting and surgery. The delayed mobility was initially attributed to lower limb weakness secondary to prolonged periods of immobilization from casting of his lower limbs. He had a striking waddling gait and proximal muscle weakness on neurological assessment. He had lower motor neuron signs predominantly in his lower limbs that were in keeping with SMA-LED. Surprisingly, he also demonstrated a brisk crossed adductor response that was not in keeping with an isolated primary neuro-muscular disorder and suggested a mixed upper and lower motor neuron pathology. The inherited neuropathy gene panel revealed a heterozygous sequence change in the DYNC1H1 gene which was present in all affected family members. CONCLUSIONS: We present the first report of a familial case series of SMA-LED with upper motor neuron signs associated with an extremely rare variant in DYNC1H1: c.1808A > T (p.Glu603Val). As per the American College of Medical Genetics and Genomics (ACMG) guidelines for variant classification, we would recommend that this variant be reclassified as `Likely Pathogenic` due to matching 1 moderate (PM1-PM6) and ≥4 supporting (PP1-PP5) criteria in the reported case series.

Early Splicing Complexes and Human Disease.

Over the last decade, our understanding of spliceosome structure and function has significantly improved, refining the study of the impact of dysregulated splicing on human disease. As a result, targeted splicing therapeutics have been developed, treating various diseases including spinal muscular atrophy and Duchenne muscular dystrophy. These advancements are very promising and emphasize the critical role of proper splicing in maintaining human health. Herein, we provide an overview of the current information on the composition and assembly of early splicing complexes-commitment complex and pre-spliceosome-and their association with human disease.

Compound heterozygous variants in MAPK8IP3 were detected in severe congenital hypotonia mimicking lethal spinal muscular atrophy.

Mitogen-activated protein kinase 8-interacting protein 3 gene (MAPK8IP3) encodes the c-Jun-amino-terminal kinase-interacting protein 3 (JIP3) and is involved in retrograde axonal transport. Heterozygous de novo pathogenic variants in MAPK8IP3 result in a neurodevelopmental disorder with or without brain abnormalities and possible axonal peripheral neuropathy. Whole-exome sequencing was performed on an individual presenting with severe congenital muscle hypotonia of neuronal origin mimicking lethal spinal muscular atrophy. Compound heterozygous rare variants (a splice and a missense) were detected in MAPK8IP3, inherited from the healthy parents. Western blot analysis in a muscle biopsy sample showed a more than 60% decrease in JIP3 expression. Here, we suggest a novel autosomal recessive phenotype of a lower motor neuron disease caused by JIP3 deficiency.

Spinal Muscular Atrophy with Progressive Myoclonic Epilepsy (SMA-PME): three new cases and review of the mutational spectrum.

BACKGROUND: Spinal muscular atrophy (SMA) could be classified as 5q and non-5q, based on the chromosomal location of causative genes. A rare form of non-5q SMA is an autosomal-recessive condition called spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME), phenotypically characterized by myoclonic and generalized seizures with progressive neurological deterioration. SMA-PME is a clinically heterogeneous disorder that arises from biallelic pathogenic variants in ASAH1 gene. METHODS: Following clinical and primary laboratory assessments, whole-exome sequencing was performed to detect the disease-causing variants in three cases of SMA-PME from different families. Also, Multiplex ligation-dependent probe amplification (MLPA) was employed for determining the copy numbers of SMN1 and SMN2 genes to rule out 5q SMA. RESULTS: Exome sequencing revealed two different homozygous missense mutations (c.109 C > A [p.Pro37Thr] or c.125 C > T [p.Thr42Met]) in exon 2 of the ASAH1 gene in the affected members of the families. Sanger sequencing of the other family members showed the expected heterozygous carriers. In addition, no clinically relevant variant was identified in patients by MLPA. CONCLUSION: This study describes two different ASAH1 mutations and the clinical picture of 3 SMA-PME patients. In addition, previously reported mutations have been reviewed. This study could help to fortify the database of this rare disease with more clinical and genomic data.

Enhanced expression of the human Survival motor neuron 1 gene from a codon-optimised cDNA transgene in vitro and in vivo.

Spinal muscular atrophy (SMA) is a neuromuscular disease particularly characterised by degeneration of ventral motor neurons. Survival motor neuron (SMN) 1 gene mutations cause SMA, and gene addition strategies to replace the faulty SMN1 copy are a therapeutic option. We have developed a novel, codon-optimised hSMN1 transgene and produced integration-proficient and integration-deficient lentiviral vectors with cytomegalovirus (CMV), human synapsin (hSYN) or human phosphoglycerate kinase (hPGK) promoters to determine the optimal expression cassette configuration. Integrating, CMV-driven and codon-optimised hSMN1 lentiviral vectors resulted in the highest production of functional SMN protein in vitro. Integration-deficient lentiviral vectors also led to significant expression of the optimised transgene and are expected to be safer than integrating vectors. Lentiviral delivery in culture led to activation of the DNA damage response, in particular elevating levels of phosphorylated ataxia telangiectasia mutated (pATM) and γH2AX, but the optimised hSMN1 transgene showed some protective effects. Neonatal delivery of adeno-associated viral vector (AAV9) vector encoding the optimised transgene to the Smn2B/- mouse model of SMA resulted in a significant increase of SMN protein levels in liver and spinal cord. This work shows the potential of a novel codon-optimised hSMN1 transgene as a therapeutic strategy for SMA.

A TRPV4 mutation caused Charcot-Marie-Tooth disease type 2C with scapuloperoneal muscular atrophy overlap syndrome and scapuloperoneal spinal muscular atrophy in one family: a case report and literature review.

BACKGROUND: Charcot-Marie-Tooth disease 2C (CMT2C) and scapuloperoneal spinal muscular atrophy (SPSMA) are different clinical phenotypes of TRPV4 mutation. The mutation of p.R316C has been reported to cause CMT2C and SPSMA separately. CASE PRESENTATION: Here, we reported a Chinese family harboring the same p.R316C variant, but with an overlap syndrome and different clinical manifestations. A 58-year-old man presented with severe scapula muscle atrophy, resulting in sloping shoulders. He also exhibited distinct muscle atrophy in his four limbs, particularly in the lower limbs. The sural nerve biopsy revealed severe loss of myelinated nerve fibers with scattered regenerating clusters and pseudo-onion bulbs. Nerve conduction study showed axon damage in both motor and sensory nerves. Sensory nerve action potentials could not be evoked in bilateral sural or superficial peroneal nerves. He was diagnosed with Charcot-Marie-Tooth disease type 2C and scapuloperoneal muscular atrophy overlap syndrome, whereas his 27-year-old son was born with clubfoot and clinodactyly. Electromyogram examination indicated chronic neurogenic changes and anterior horn cells involvement. Although there was no obvious weakness or sensory symptoms, early SPSMA could be considered for him. CONCLUSIONS: A literature review of the clinical characteristics in CMT2C and SPSMA patients with TRPV4 mutation suggested that our case was distinct due to the overlap syndrome and phenotype variation. Altogether, this case broadened the phenotype spectrum and provided the nerve biopsy pathological details of TRPV4-related neuropathies.

Evaluation of the orally bioavailable 4-phenylbutyrate-tethered trichostatin A analogue AR42 in models of spinal muscular atrophy.

Proximal spinal muscular atrophy (SMA) is a leading genetic cause for infant death in the world and results from the selective loss of motor neurons in the spinal cord. SMA is a consequence of low levels of SMN protein and small molecules that can increase SMN expression are of considerable interest as potential therapeutics. Previous studies have shown that both 4-phenylbutyrate (4PBA) and trichostatin A (TSA) increase SMN expression in dermal fibroblasts derived from SMA patients. AR42 is a 4PBA-tethered TSA derivative that is a very potent histone deacetylase inhibitor. SMA patient fibroblasts were treated with either AR42, AR19 (a related analogue), 4PBA, TSA or vehicle for 5 days and then immunostained for SMN localization. AR42 as well as 4PBA and TSA increased the number of SMN-positive nuclear gems in a dose-dependent manner while AR19 did not show marked changes in gem numbers. While gem number was increased in AR42-treated SMA fibroblasts, there were no significant changes in FL-SMN mRNA or SMN protein. The neuroprotective effect of this compound was then assessed in SMNΔ7 SMA (SMN2+/+;SMNΔ7+/+;mSmn-/-) mice. Oral administration of AR42 prior to disease onset increased the average lifespan of SMNΔ7 SMA mice by ~ 27% (20.1 ± 1.6 days for AR42-treated mice vs. 15.8 ± 0.4 days for vehicle-treated mice). AR42 treatment also improved motor function in these mice. AR42 treatment inhibited histone deacetylase (HDAC) activity in treated spinal cord although it did not affect SMN protein expression in these mice. AKT and GSK3ß phosphorylation were both significantly increased in SMNΔ7 SMA mouse spinal cords. In conclusion, presymptomatic administration of the HDAC inhibitor AR42 ameliorates the disease phenotype in SMNΔ7 SMA mice in a SMN-independent manner possibly by increasing AKT neuroprotective signaling.

[Treatment of Spinal Muscular Atrophy].

Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease that predominantly affects motor neurons, resulting in progressive muscular atrophy and weakness. SMA arises due to insufficient levels of the survival motor neuron (SMN) protein as a result of homozygous disruption of the SMN1 gene. The SMN protein is also produced by the paralogous gene SMN2, but the amount of SMN produced is minimal due to a defect in the splicing process. Nusinersen, an antisense oligonucleotide, and risdiplam, an oral small molecule, have been developed to repair SMN2 splicing failures to facilitate adequate production of the SMN protein. Onasemnogene abeparvovec utilizes a nonreplicating adeno-associated virus 9 to provide a copy of the gene encoding the SMN protein. This therapy has led to a dramatic advancement in SMA treatment. Here, we introduce current treatment strategies for SMA.

Genotype and clinical phenotype analysis of a Family with Kennedy disease.

To investigate the clinical phenotype-genotype correlations of a family with Kennedy disease (KD) and improve our understanding of the disease. KD was confirmed after clinical phenotypic analyses, laboratory tests, polymerase chain reaction assays for cytosine-adenine-guanine (CAG) repeats, and neuro-electrophysiological tests. The disease was assessed using the KD1234 scale and the spinal and bulbar muscular atrophy functional rating scale. The average age of disease onset was 30.8 ± 2.85 years. Clinically diagnosed members had 48 CAG repeats (≥35 is abnormal) in the androgen receptor gene. The patients exhibited gynecomastia and testicular dysfunction. The lesions mainly involved the medulla oblongata and spinal cord. Progesterone and serum creatine kinase levels were significantly high. Electromyography showed chronic neurogenic damage and abnormal sensory and motor conduction in family members who did not participate in sports, exercise, or physical hobbies. Our study showed that this family had a stable inheritance of CAG repeats, and the genotype was consistent with the clinical phenotype. Gynecomastia was the first symptom, with progressive androgen resistance resulting in testicular atrophy, infertility, and sexual dysfunction. Changes in serum creatine kinase may indicate the progression or relief of symptoms, and rehabilitation may delay the progression of muscle atrophy.