Genome-wide identification of tandem repeats associated with splicing variation across 49 tissues in humans.

Tandem repeats (TRs) are one of the largest sources of polymorphism, and their length is associated with gene regulation. Although previous studies reported several tandem repeats regulating gene splicing in cis (spl-TRs), no large-scale study has been conducted. In this study, we established a genome-wide catalog of 9537 spl-TRs with a total of 58,290 significant TR-splicing associations across 49 tissues (false discovery rate 5%) by using Genotype-Tissue expression (GTex) Project data. Regression models explaining splicing variation by using spl-TRs and other flanking variants suggest that at least some of the spl-TRs directly modulate splicing. In our catalog, two spl-TRs are known loci for repeat expansion diseases, spinocerebellar ataxia 6 (SCA6) and 12 (SCA12). Splicing alterations by these spl-TRs were compatible with those observed in SCA6 and SCA12. Thus, our comprehensive spl-TR catalog may help elucidate the pathomechanism of genetic diseases.

Subcellular localization and ER-mediated cytotoxic function of α1A and α1ACT in spinocerebellar ataxia type 6.

Spinocerebellar ataxia type 6 (SCA6) is a polyglutamine (polyQ) disease, which is caused by the elongation of CAG repeats encoding polyQ in the CACNA1A gene. The CACNA1A gene encodes two proteins, namely, α1A (a subunit of the plasma membrane calcium channel), which is translated in its entire length, and α1ACT, which is translated from the second cistron, and both proteins have a polyQ tract. The α1A-polyQ and α1ACT-polyQ proteins with an elongated polyQ stretch have been reported to form aggregates in cells and induce neuronal cell death, but the subcellular localization of these proteins and their cytotoxic properties remain unclear. In this study, we first analyzed SCA6 model mice and found that α1A-polyQlong localized mainly to the Golgi apparatus, whereas a portion of α1ACT-polyQlong localized to the nucleus. Analysis using Neuro2a cells also showed similar subcellular localizations of these proteins, and a proportion of both proteins localized to the endoplasmic reticulum (ER). Cytotoxic studies demonstrated that both proteins induce both the ER stress response and apoptosis, indicating that they are able to induce ER stress-induced apoptosis.

Temporal Relationship between Impairment of Cerebellar Motor Learning and Deterioration of Ataxia in Patients with Cerebellar Degeneration.

Ataxia and impaired motor learning are both fundamental features in diseases affecting the cerebellum. However, it remains unclarified whether motor learning is impaired only when ataxia clearly manifests, nor it is known whether the progression of ataxia, the speed of which often varies among patients with the same disease, can be monitored by examining motor learning. We evaluated motor learning and ataxia at intervals of several months in 40 patients with degenerative conditions [i.e., multiple system atrophy (MSA), Machado-Joseph disease (MJD)/spinocerebellar ataxia type 3 (SCA3), SCA6, and SCA31]. Motor learning was quantified as the adaptability index (AI) in the prism adaptation task and ataxia was scored using the Scale for the Assessment and Rating of Ataxia (SARA). We found that AI decreased most markedly in both MSA-C and MSA-P, moderately in MJD, and mildly in SCA6 and SCA31. Overall, the AI decrease occurred more rapidly than the SARA score increase. Interestingly, AIs remained normal in purely parkinsonian MSA-P patients (n = 4), but they dropped into the ataxia range when these patients started to show ataxia. The decrease in AI during follow-up (dAI/dt) was significant in patients with SARA scores < 10.5 compared with patients with SARA scores ≥ 10.5, indicating that AI is particularly useful for diagnosing the earlier phase of cerebellar degeneration. We conclude that AI is a useful marker for progressions of cerebellar diseases, and that evaluating the motor learning of patients can be particularly valuable for detecting cerebellar impairment, which is often masked by parkinsonisms and other signs.

A Novel de novo KIF1A Mutation in a Patient with Ataxia, Intellectual Disability and Mild Foot Deformity.

Early-onset ataxias are often difficult to diagnose due to the genetic and phenotypic heterogeneity of patients. Whole exome sequencing (WES) is a powerful method for determining causative mutations of early-onset ataxias. We report a case in which a novel de novo KIF1A mutation was identified in a patient with ataxia, intellectual disability and mild foot deformity.A patient presented with sporadic forms of ataxia with mild foot deformity, intellectual disability, peripheral neuropathy, pyramidal signs, and orthostatic hypotension. WES was used to identify a novel de novo mutation in KIF1A, a known causative gene of neurodegeneration and spasticity with or without cerebellar atrophy or cortical visual impairment syndrome (NESCAVS).We report a novel phenotype of NESCAVS that is associated with a novel de novo missense mutation in KIF1A, which provides valuable information for the diagnosis of NESCAVS even in the era of WES. Early rehabilitation of patients with NESCAVS may prevent symptom worsening and improve the disease course.

Six years' accomplishment of the Initiative on Rare and Undiagnosed Diseases: nationwide project in Japan to discover causes, mechanisms, and cures.

The identification of causative genetic variants for hereditary diseases has revolutionized clinical medicine and an extensive collaborative framework with international cooperation has become a global trend to understand rare disorders. The Initiative on Rare and Undiagnosed Diseases (IRUD) was established in Japan to provide accurate diagnosis, discover causes, and ultimately provide cures for rare and undiagnosed diseases. The fundamental IRUD system consists of three pillars: IRUD diagnostic coordination, analysis centers (IRUD-ACs), and a data center (IRUD-DC). IRUD diagnostic coordination consists of clinical centers (IRUD-CLs) and clinical specialty subgroups (IRUD-CSSs). In addition, the IRUD coordinating center (IRUD-CC) manages the entire IRUD system and temporarily operates the IRUD resource center (IRUD-RC). By the end of March 2021, 6301 pedigrees consisting of 18,136 individuals were registered in the IRUD. The whole-exome sequencing method was completed in 5136 pedigrees, and a final diagnosis was established in 2247 pedigrees (43.8%). The total number of aberrated genes and pathogenic variants was 657 and 1718, among which 1113 (64.8%) were novel. In addition, 39 novel disease entities or phenotypes with 41 aberrated genes were identified. The 6-year endeavor of IRUD has been an overwhelming success, establishing an all-Japan comprehensive diagnostic and research system covering all geographic areas and clinical specialties/subspecialties. IRUD has accurately diagnosed diseases, identified novel aberrated genes or disease entities, discovered many candidate genes, and enriched phenotypic and pathogenic variant databases. Further promotion of the IRUD is essential for determining causes and developing cures for rare and undiagnosed diseases.

Methionine homozygosity for PRNP polymorphism and susceptibility to human prion diseases.

BACKGROUND: No studies have assessed the independent association of methionine homozygosity at codon 129 with the susceptibility to prion diseases, controlling for the effects of the codon 219 polymorphisms and other potential confounders, using a large-scale population-based dataset. METHODS: We conducted a case-control study using a Japanese nationwide surveillance database for prion diseases. The main exposure was methionine homozygosity at codon 129, and the outcome was development of prion diseases. Multivariable logistic regression models were employed for specific disease subtypes (sporadic Creutzfeldt-Jakob disease (CJD), genetic CJD and Gerstmann-Sträussler-Scheinker disease (GSS)). RESULTS: Of 5461 patients registered in the database, 2440 cases and 796 controls remained for the analysis. The cases comprised 1676 patients with sporadic CJD (69%), 649 with genetic CJD (27%) and 115 with GSS (5%). For patients with methionine homozygosity, potential risk for occurring prion diseases: adjusted OR (95% CI) was 2.21 (1.46 to 3.34) in sporadic CJD, 0.47 (0.32 to 0.68) in genetic CJD and 0.3 (0.17 to 0.55) in GSS. Among patients with specific prion protein abnormalities, the potential risk was 0.27 (0.17 to 0.41) in genetic CJD with 180 Val/Ile, 1.66 (0.65 to 5.58) in genetic CJD with 200 Glu/Lys, 3.97 (1.2 to 24.62) in genetic CJD with 232 Met/Arg and 0.71 (0.34 to 1.67) in GSS with 102 Pro/Leu. CONCLUSIONS: Methionine homozygosity at codon 129 was predisposing to sporadic CJD, but protective against genetic CJD and GSS, after adjustment for codon 219 polymorphism effect. However, the impacts differed completely among patients with specific prion protein abnormalities.

Soluble APP-α and APP-ß in cerebrospinal fluid as potential biomarkers for differential diagnosis of mild cognitive impairment.

OBJECTIVES: Concentrations of soluble amyloid precursor proteins-α (sAPPα) and -ß (sAPPß) in cerebrospinal fluid (CSF) may reflect the neuropathology of Alzheimer's disease (AD). We previously reported that the concentrations of both sAPPα and sAPPß were significantly higher in patients with mild cognitive impairment (MCI) due to AD (MCI-AD) than in control subjects without cognitive impairment. The present study analyzed whether these sAPPs are useful in the differential diagnosis of MCI. METHODS: A modified and sensitive method was used to analyze concentrations of sAPPα and sAPPß in CSF of patients with MCI-AD (n = 30) and MCI due to other causes (MCI-others) (n = 24). Phosphorylated tau (p-tau) and amyloid ß-protein 42 (Aß42) were also analyzed using standard methods. RESULTS: CSF concentrations of sAPPα and sAPPß were significantly higher in the MCI-AD than in the MCI-others group (p < 0.001). Furthermore, concentrations of both sAPPα and sAPPß were highly correlated with the concentration of p-tau, consistent with our previous report. CONCLUSIONS: Measurement of both sAPPs in CSF using sensitive methods can be helpful in the precise differential diagnosis of patients with MCI.

Tandem internal models execute motor learning in the cerebellum.

In performing skillful movement, humans use predictions from internal models formed by repetition learning. However, the computational organization of internal models in the brain remains unknown. Here, we demonstrate that a computational architecture employing a tandem configuration of forward and inverse internal models enables efficient motor learning in the cerebellum. The model predicted learning adaptations observed in hand-reaching experiments in humans wearing a prism lens and explained the kinetic components of these behavioral adaptations. The tandem system also predicted a form of subliminal motor learning that was experimentally validated after training intentional misses of hand targets. Patients with cerebellar degeneration disease showed behavioral impairments consistent with tandemly arranged internal models. These findings validate computational tandemization of internal models in motor control and its potential uses in more complex forms of learning and cognition.

Characterization of Sporadic Creutzfeldt-Jakob Disease and History of Neurosurgery to Identify Potential Iatrogenic Cases.

We previously reported a phenotype of Creutzfeldt-Jakob disease (CJD), CJD-MMiK, that could help identify iatrogenic CJD. To find cases mimicking CJD-MMiK, we investigated clinical features and pathology of 1,155 patients with diagnosed sporadic CJD or unclassified CJD with and without history of neurosurgery. Patients with history of neurosurgery more frequently had an absence of periodic sharp-wave complexes on electroencephalogram than patients without a history of neurosurgery. Among 27 patients with history of neurosurgery, 5 had no periodic sharp-wave complexes on electroencephalogram. We confirmed 1 case of CJD-MMiK and suspected another. Both had methionine homozygosity at codon 129 of the prion protein gene and hyperintensity lesions in the thalamus on magnetic resonance images of the brain, which might be a clinical marker of CJD-MMiK. A subgroup with a history of neurosurgery and clinical features mimicking dura mater graft-associated CJD might have been infected during neurosurgery and had symptoms develop after many years.

MM2-type sporadic Creutzfeldt-Jakob disease: new diagnostic criteria for MM2-cortical type.

OBJECTIVE: To clinically diagnose MM2-cortical (MM2C) and MM2-thalamic (MM2T)-type sporadic Creutzfeldt-Jakob disease (sCJD) at early stage with high sensitivity and specificity. METHODS: We reviewed the results of Creutzfeldt-Jakob disease Surveillance Study in Japan between April 1999 and September 2019, which included 254 patients with pathologically confirmed prion diseases, including 9 with MM2C-type sCJD (MM2C-sCJD) and 10 with MM2T-type sCJD (MM2T-sCJD), and 607 with non-prion diseases. RESULTS: According to the conventional criteria of sCJD, 4 of 9 patients with MM2C- and 7 of 10 patients with MM2T-sCJD could not be diagnosed with probable sCJD until their death. Compared with other types of sCJD, patients with MM2C-sCJD showed slower progression of the disease and cortical distribution of hyperintensity lesions on diffusion-weighted images of brain MRI. Patients with MM2T-sCJD also showed relatively slow progression and negative results for most of currently established investigations for diagnosis of sCJD. To clinically diagnose MM2C-sCJD, we propose the new criteria; diagnostic sensitivity and specificity to distinguish 'probable' MM2C-sCJD from other subtypes of sCJD, genetic or acquired prion diseases and non-prion disease controls were 77.8% and 98.5%, respectively. As for MM2T-sCJD, clinical and laboratory features are not characterised enough to develop its diagnostic criteria. CONCLUSIONS: MM2C-sCJD can be diagnosed at earlier stage using the new criteria with high sensitivity and specificity, although it is still difficult to diagnose MM2T-sCJD clinically.

Ataxic phenotype with altered CaV3.1 channel property in a mouse model for spinocerebellar ataxia 42.

Spinocerebellar ataxia 42 (SCA42) is a neurodegenerative disorder recently shown to be caused by c.5144G > A (p.Arg1715His) mutation in CACNA1G, which encodes the T-type voltage-gated calcium channel CaV3.1. Here, we describe a large Japanese family with SCA42. Postmortem pathological examination revealed severe cerebellar degeneration with prominent Purkinje cell loss without ubiquitin accumulation in an SCA42 patient. To determine whether this mutation causes ataxic symptoms and neurodegeneration, we generated knock-in mice harboring c.5168G > A (p.Arg1723His) mutation in Cacna1g, corresponding to the mutation identified in the SCA42 family. Both heterozygous and homozygous mutants developed an ataxic phenotype from the age of 11-20 weeks and showed Purkinje cell loss at 50 weeks old. Degenerative change of Purkinje cells and atrophic thinning of the molecular layer were conspicuous in homozygous knock-in mice. Electrophysiological analysis of Purkinje cells using acute cerebellar slices from young mice showed that the point mutation altered the voltage dependence of CaV3.1 channel activation and reduced the rebound action potentials after hyperpolarization, although it did not significantly affect the basic properties of synaptic transmission onto Purkinje cells. Finally, we revealed that the resonance of membrane potential of neurons in the inferior olivary nucleus was decreased in knock-in mice, which indicates that p.Arg1723His CaV3.1 mutation affects climbing fiber signaling to Purkinje cells. Altogether, our study shows not only that a point mutation in CACNA1G causes an ataxic phenotype and Purkinje cell degeneration in a mouse model, but also that the electrophysiological abnormalities at an early stage of SCA42 precede Purkinje cell loss.

Alternative splicing in the C-terminal tail of Cav2.1 is essential for preventing a neurological disease in mice.

Alternative splicing (AS) that occurs at the final coding exon (exon 47) of the Cav2.1 voltage-gated calcium channel (VGCC) gene produces two major isoforms in the brain, MPI and MPc. These isoforms differ in their splice acceptor sites; human MPI is translated into a polyglutamine tract associated with spinocerebellar ataxia type 6 (SCA6), whereas MPc splices to an immediate stop codon, resulting in a shorter cytoplasmic tail. To gain insight into the functional role of the AS in vivo and whether modulating the splice patterns at this locus can be a potential therapeutic strategy for SCA6, here we created knockin mice that exclusively express MPc by inserting the splice-site mutation. The resultant Cacna1aCtmKO/CtmKO mice developed non-progressive neurological phenotypes, featuring early-onset ataxia and absence seizure without significant alterations in the basic properties of the channel. Interactions of Cav2.1 with Cavß4 and Rimbp2 were significantly reduced while those with GABAB2 were enhanced in the cerebellum of Cacna1aCtmKO/CtmKO mice. Treatment with the GABAB antagonist CGP35348 partially rescued the motor impairments seen in Cacna1aCtmKO/CtmKO mice. These results suggest that the carboxyl-terminal domain of Cav2.1 is not essential for maintaining the basic properties of the channel in the cerebellar Purkinje neurons but is involved in multiple interactions of Cav2.1 with other proteins, and plays an essential role in preventing a complex neurological disease.

Impaired striatal dopamine release in homozygous Vps35 D620N knock-in mice.

Point mutations in the vacuolar protein sorting 35 gene (VPS35) have been associated with an autosomal dominant form of late-onset Parkinson disease (PARK17), but there has been considerable debate over whether it is caused by a loss- or gain-of-function mechanism and over the intracellular target site of neurotoxicity. To investigate the pathogenesis of PARK17 in vivo, we generated Vps35 D620N knock-in (KI) mice, expressing the homologous mutant protein with endogenous patterns of expression, simultaneously with Vps35 deletion 1 (Del1) mice, which carry 1bp deletion in the exon15 of Vps35, by CRISPR/Cas9-mediated genome engineering. Neither homozygous nor heterozygous Vps35 D620N KI mice suffered from premature death or developed clear neurodegeneration up to 70 weeks of age. Vps35 Del1 allele appeared to be a null or at least severely hypomorphic allele and homozygous Vps35 Del1 showed early embryonic lethality. Heterozygous crossings between Del1 and D620N knock-in mice revealed that the D620N/Del1 compound heterozygous mice, but not heterozygous Del1 mice, suffered from survival disadvantage. In vivo microdialysis showed that DA release evoked by 120 mM potassium chloride was significantly reduced in the caudate putamen of adult homozygous Vps35 D620N KI mice. Taken together, these results suggest that Vps35 D620N allele is a partial-loss-of-function allele and that such a genetic predisposition and age-related alterations in the nigrostriatal dopamine system cooperatively influence the pathogenesis of PARK17.

Biochemical features of genetic Creutzfeldt-Jakob disease with valine-to-isoleucine substitution at codon 180 on the prion protein gene.

Valine-to-isoleucine substitution at codon 180 of the prion protein gene is only observed in patients with Creutzfeldt-Jakob disease and accounts for approximately half of all cases of genetic prion disease in Japan. In the present study, we investigated the biochemical characteristics of valine-to-isoleucine substitution at codon 180 in the prion protein gene, using samples obtained from the autopsied brains of seven patients with genetic Creutzfeldt-Jakob disease exhibiting this mutation (diagnoses confirmed via neuropathological examination). Among these patients, we observed an absence of diglycosylated and monoglycosylated forms of PrPres at codon 181. Our findings further indicated that the abnormal prion proteins were composed of at least three components, although smaller carboxyl-terminal fragments were predominant. Western blot analyses revealed large amounts of PrPres in the cerebral neocortices, where neuropathological examination revealed marked spongiosis. Relatively smaller amounts of PrPres were detected in the hippocampus, where milder spongiosis was observed, than in the cerebral neocortex. These findings indicate that abnormal prion proteins in the neocortex are associated with severe toxicity, resulting in severe spongiosis. Our findings further indicate that the valine-to-isoleucine substitution is not a polymorphism, but rather an authentic pathogenic mutation associated with specific biochemical characteristics that differ from those observed in sporadic Creutzfeldt-Jakob disease.

Update: Dura Mater Graft-Associated Creutzfeldt-Jakob Disease - Japan, 1975-2017.

Creutzfeldt-Jakob disease (CJD) is a fatal neurodegenerative disorder that, according to the most well accepted hypothesis (1), is caused by replicating, transmissible, abnormal forms of a host-encoded prion protein (prions). Most CJD cases occur spontaneously (sporadic CJD) or are inherited (genetic CJD). Iatrogenic CJD can occur after exposure to prion-contaminated instruments or products in medical/surgical settings. Cadaveric dura mater graft-associated CJD (dCJD) accounts for a common form of iatrogenic CJD. This report summarizes the epidemiologic features of 154 cases of dCJD identified in Japan during 1975-2017; these cases account for >60% of dCJD cases reported worldwide (1,2). The unusually high prevalence of dCJD in Japan was first reported in 1997 (3). In 2008, a single brand of graft (Lyodura [B. Braun Melsungen AG, Melsungen, Germany]), frequently used as a patch in neurosurgical procedures, was identified as the probable vehicle of transmission (4). No international recall of the implicated Lyodura occurred, the product had a relatively long shelf life, and the grafts were used frequently in Japanese patients with non-life-threatening conditions (4,5). Since 2008, additional cases have been ascertained, reflecting the identification of previously missed cases and the occurrence of new cases with longer latency periods (interval from exposure to symptom onset) for dCJD (up to 30 years), underscoring the importance of maintaining surveillance for dCJD.

Clinical features of the behavioural variant of frontotemporal dementia that are useful for predicting underlying pathological subtypes of frontotemporal lobar degeneration.

BACKGROUND: The behavioural variant of frontotemporal dementia (bvFTD) is the most common phenotype of frontotemporal lobar degeneration (FTLD). FTLD is divided into three main pathological subtypes: tau-positive FTLD (FTLD-tau), FTLD-TAR DNA-binding protein (TDP), and FTLD-Fused in sarcoma (FUS). At present, it is difficult to predict the underlying pathological subtypes of sporadic bvFTD before a patient's death. METHODS: We retrospectively investigated the clinical features of 34 Japanese patients with sporadic bvFTD, with or without motor neuron disease (MND), who had been pathologically diagnosed with FTLD. We examined whether, and how, the clinical features differed among Pick's disease, FTLD-TDP, and FTLD-FUS patients. RESULTS: Six of the 34 patients developed MND during the course of bvFTD. These six bvFTD-MND patients were all pathologically diagnosed with FTLD-TDP. The other 28 patients were composed of 12 FTLD-tau patients including 11 Pick's disease patients, 8 FTLD-TDP patients, and 8 FTLD-FUS patients. A comparison of the clinical features of the three pathological subtypes of the 33 patients demonstrated that the age at onset was significantly younger in FTLD-FUS patients than in Pick's disease or FTLD-TDP patients. Furthermore, while hyperorality and dietary changes in the early stage of the disease were present in approximately 40% of Pick's disease and FTLD-FUS patients, they were absent in FTLD-TDP patients. CONCLUSION: The comorbidity of MND, a younger age at onset, and hyperorality and dietary changes in the early stage may be useful clinical features for predicting underlying pathological subtypes of sporadic bvFTD. The results of our study should be confirmed by prospective studies employing a larger number of cases.

Loss of MyD88 alters neuroinflammatory response and attenuates early Purkinje cell loss in a spinocerebellar ataxia type 6 mouse model.

Spinocerebellar ataxia type 6 (SCA6) is dominantly inherited neurodegenerative disease, caused by an expansion of CAG repeat encoding a polyglutamine (PolyQ) tract in the Cav2.1 voltage-gated calcium channel. Its key pathological features include selective degeneration of the cerebellar Purkinje cells (PCs), a common target for PolyQ-induced toxicity in various SCAs. Mutant Cav2.1 confers toxicity primarily through a toxic gain-of-function mechanism; however, its molecular basis remains elusive. Here, we studied the cerebellar gene expression patterns of young Sca6-MPI(118Q/118Q) knockin (KI) mice, which expressed mutant Cav2.1 from an endogenous locus and recapitulated many phenotypic features of human SCA6. Transcriptional signatures in the MPI(118Q/118Q) mice were distinct from those in the Sca1(154Q/2Q) mice, a faithful SCA1 KI mouse model. Temporal expression profiles of the candidate genes revealed that the up-regulation of genes associated with microglial activation was initiated before PC degeneration and was augmented as the disease progressed. Histological analysis of the MPI(118Q/118Q) cerebellum showed the predominance of M1-like pro-inflammatory microglia and it was concomitant with elevated expression levels of tumor necrosis factor, interleukin-6, Toll-like receptor (TLR) 2 and 7. Genetic ablation of MyD88, a major adaptor protein conveying TLR signaling, altered expression patterns of M1/M2 microglial phenotypic markers in the MPI(118Q/118Q) cerebellum. More importantly, it ameliorated PC loss and partially rescued motor impairments in the early disease phase. These results suggest that early neuroinflammatory response may play an important role in the pathogenesis of SCA6 and its modulation could pave the way for slowing the disease progression during the early stage of the disease.

Consensus Paper: Neuroimmune Mechanisms of Cerebellar Ataxias.

In the last few years, a lot of publications suggested that disabling cerebellar ataxias may develop through immune-mediated mechanisms. In this consensus paper, we discuss the clinical features of the main described immune-mediated cerebellar ataxias and address their presumed pathogenesis. Immune-mediated cerebellar ataxias include cerebellar ataxia associated with anti-GAD antibodies, the cerebellar type of Hashimoto's encephalopathy, primary autoimmune cerebellar ataxia, gluten ataxia, Miller Fisher syndrome, ataxia associated with systemic lupus erythematosus, and paraneoplastic cerebellar degeneration. Humoral mechanisms, cell-mediated immunity, inflammation, and vascular injuries contribute to the cerebellar deficits in immune-mediated cerebellar ataxias.

Efficacy of intravenous methylprednisolone pulse therapy in patients with multiple sclerosis and neuromyelitis optica.

BACKGROUND: No large-scale studies have compared the efficacy of intravenous methylprednisolone pulse therapy (IVMP) for multiple sclerosis (MS) and neuromyelitis optica (NMO). OBJECTIVE: To explain differences in treatment responses of MS and NMO patients to IVMP. METHODS: Changes in neurological symptoms/signs and Expanded Disability Status Scale (EDSS) scores before and within 1 week of IVMP completion were obtained in 2010 at 28 institutions, and retrospectively collated from 271 MS (478 courses) and 73 NMO (118 courses) cases. RESULTS: In MS patients, decreased EDSS score was significant after the first (-0.8 ± 0.9), second (-0.7 ± 0.9), and third (-0.7 ± 0.8) courses (p < 0.05), but not after the fourth (-0.3 ± 0.7) and fifth (-0.5 ± 0.6). However, decreased EDSS score was only significant after the first course (-0.5 ± 1.5, p < 0.05) in NMO patients. EDSS score was significantly decreased in MS compared with NMO patients at the first course (p < 0.05), but not thereafter. Model analysis for EDSS score improvement at the first course, adjusting for covariates, showed significantly greater decreases in MS compared with NMO patients (p < 0.05). CONCLUSION: IVMP is effective in MS from the first to third courses, and in NMO at the first course. Additionally, IVMP is more efficacious in MS than NMO patients, even at the first course.