The CGG repeat expansion in RILPL1 is associated with oculopharyngodistal myopathy type 4.

Recent studies indicate that CGG repeat expansions in LRP12, GIPC1, and NOTCH2NLC are associated with oculopharyngodistal myopathy (OPDM) types 1, 2, and 3, respectively. However, some clinicopathologically confirmed OPDM cases continue to have unknown genetic causes. Here, through a combination of long-read whole-genome sequencing (LRS), repeat-primed polymerase chain reaction (RP-PCR), and fluorescence amplicon length analysis PCR (AL-PCR), we found that a CGG repeat expansion in the 5' UTR of RILPL1 is associated with familial and simplex OPDM type 4 (OPDM4). The number of repeats ranged from 139 to 197. Methylation analysis indicates that the methylation levels in RILPL1 were unaltered in OPDM4 individuals. Analyses of muscle biopsies suggested that the expanded CGG repeat might be translated into a toxic poly-glycine protein that co-localizes with p62 in intranuclear inclusions. Moreover, analyses suggest that the toxic RNA gain-of-function effects also contributed to the pathogenesis of this disease. Intriguingly, all four types of OPDM have been found to be associated with the CGG repeat expansions located in 5' UTRs. This finding suggests that a common pathogenic mechanism, driven by the CGG repeat expansion, might underlie all cases of OPDM.

Non-coding CGG repeat expansion in LOC642361/NUTM2B-AS1 is associated with a phenotype of oculopharyngodistal myopathy.

BACKGROUND: Oculopharyngodistal myopathy (OPDM) is a rare adult-onset neuromuscular disease, associated with CGG repeat expansions in the 5' untranslated region of LRP12, GIPC1, NOTCH2NLC and RILPL1. However, the genetic cause of a proportion of pathoclinically confirmed cases remains unknown. METHODS: A total of 26 OPDM patients with unknown genetic cause(s) from 4 tertiary referral hospitals were included in this study. Clinical data and laboratory findings were collected. Muscle samples were observed by histological and immunofluorescent staining. Long-read sequencing was initially conducted in six patients with OPDM. Repeat-primed PCR was used to screen the CGG repeat expansions in LOC642361/NUTM2B-AS1 in all 26 patients. RESULTS: We identified CGG repeat expansion in the non-coding transcripts of LOC642361/NUTM2B-AS1 in another two unrelated Chinese cases with typical pathoclinical features of OPDM. The repeat expansion was more than 70 times in the patients but less than 40 times in the normal controls. Both patients showed no leucoencephalopathy but one showed mild cognitive impairment detected by Montreal Cognitive Assessment. Rimmed vacuoles and p62-positive intranuclear inclusions (INIs) were identified in muscle pathology, and colocalisation of CGG RNA foci with p62 was also found in the INIs of patient-derived fibroblasts. CONCLUSIONS: We identified another two unrelated cases with CGG repeat expansion in the long non-coding RNA of the LOC642361/NUTM2B-AS1 gene, presenting with a phenotype of OPDM. Our cases broadened the recognised phenotypic spectrum and pathogenesis in the disease associated with CGG repeat expansion in LOC642361/NUTM2B-AS1.

Blockage of MLKL prevents myelin damage in experimental diabetic neuropathy.

SignificanceDiabetic neuropathy is a commonly occurring complication of diabetes that affects hundreds of millions of patients worldwide. Patients suffering from diabetic neuropathy experience abnormal sensations and have damage in their peripheral nerve axons as well as myelin, a tightly packed Schwann cell sheath that wraps around axons to provide insulation and increases electrical conductivity along the nerve fibers. The molecular events underlying myelin damage in diabetic neuropathy are largely unknown, and there is no efficacious treatment for the disease. The current study, using a diabetic mouse model and human patient nerve samples, uncovered a molecular mechanism underlying myelin sheath damage in diabetic neuropathy and provides a potential treatment strategy for the disease.

Integrative multi-omics analysis identifies genetically supported druggable targets and immune cell specificity for myasthenia gravis.

BACKGROUND: Myasthenia gravis (MG) is a chronic autoimmune disorder characterized by fluctuating muscle weakness. Despite the availability of established therapies, the management of MG symptoms remains suboptimal, partially attributed to lack of efficacy or intolerable side-effects. Therefore, new effective drugs are warranted for treatment of MG. METHODS: By employing an analytical framework that combines Mendelian randomization (MR) and colocalization analysis, we estimate the causal effects of blood druggable expression quantitative trait loci (eQTLs) and protein quantitative trait loci (pQTLs) on the susceptibility of MG. We subsequently investigated whether potential genetic effects exhibit cell-type specificity by utilizing genetic colocalization analysis to assess the interplay between immune-cell-specific eQTLs and MG risk. RESULTS: We identified significant MR results for four genes (CDC42BPB, CD226, PRSS36, and TNFSF12) using cis-eQTL genetic instruments and three proteins (CTSH, PRSS8, and CPN2) using cis-pQTL genetic instruments. Six of these loci demonstrated evidence of colocalization with MG susceptibility (posterior probability > 0.80). We next undertook genetic colocalization to investigate cell-type-specific effects at these loci. Notably, we identified robust evidence of colocalization, with a posterior probability of 0.854, linking CTSH expression in TH2 cells and MG risk. CONCLUSIONS: This study provides crucial insights into the genetic and molecular factors associated with MG susceptibility, singling out CTSH as a potential candidate for in-depth investigation and clinical consideration. It additionally sheds light on the immune-cell regulatory mechanisms related to the disease. However, further research is imperative to validate these targets and evaluate their feasibility for drug development.

A synonymous codon variant altering splicing of RBCK1 expands the phenotype and genotype spectra of polyglucosan body myopathy 1.

Polyglucosan body myopathy type 1 (PGBM1, OMIM #615895.) is a rare autosomal recessive disorder caused by RBCK1 mutations. The patients displayed polyglucosan accumulation in skeletal and cardiac muscles, giving rise to loss of ambulation and heart failure with or without immune system dysregulation. So far, only 24 patients have been reported, all of whom exhibited symptoms before adulthood. Here, we reported the first case of an adult-onset PGBM1 patient with a novel compound heterozygous RBCK1 gene mutation consisting of a nonsense and synonymous variant affecting splicing.

Different sensorimotor mechanism in fast and slow progression amyotrophic lateral sclerosis.

The huge heterogeneity of the disease progression rate may cause inconsistent findings between local activity and functional connectivity of the primary sensorimotor area (PSMA) in amyotrophic lateral sclerosis (ALS). For illustration of this hypothesis, resting-state fMRI (RS-fMRI) data were collected and analyzed on 38 "definite" or "probable" ALS patients (19 fast and 19 slow, cut off median = 0.41) and 37 matched healthy controls. Amplitude of low frequency fluctuations (ALFFs) and functional connectivity strength (FCS) were analyzed within the PSMA. There was a decreased ALFF (pFDR <.05) and FCS (p = .022) in all ALS patients. The two metrics shared about 50% of variance (R = .7) and both showed significant positive correlation with ALS Functional Rating Scale-Revised (ALSFRS-R) in the fast (p values <.034) but not in the slow progression groups. Interestingly, when regressing out the ALFF, the PSMA network FCS, especially the inter-hemisphere FCS, showed negative correlation with the ALSFRS-R score in the slow (R = -.54, p = .026) but not the fast progression group. In summary, the current results suggest that RS-fMRI local activity and network functional connectivity accounts for the severity differently in the slow and fast progression ALS patients.

Involvement of Ocular Muscles in Patients With Myasthenia Gravis With Nonocular Onset.

BACKGROUND: Myasthenia gravis (MG) is an autoimmune disorder involving neuromuscular junctions and more than half of MG patients manifested with extraocular muscle weakness initially. In the remained patients, ocular weakness may occur later in the course of the disease. However, little data are available about ocular involvement in such patients. Therefore, the study aims to investigate ocular weakness in MG patients with nonocular onset and evaluate the associated factors influencing it. METHODS: In our monocentric retrospective study, 54 adult-onset patients with MG with nonocular onset were included and were followed up for at least 2 years from the onset. The primary outcome was the occurrence of ptosis, diplopia, or both. Kaplan-Meier analysis was performed to estimate the time to the ocular weakness, and log-rank tests were used to analyze the association between clinical characteristics and ocular weakness. Multivariate Cox proportional hazards regression models were used to identify factors associated with ocular involvement. RESULTS: A total of 47 (87.0%) patients developed ocular weakness during the study period. The median time to ocular weakness was 6.0 months. Time to the ocular involvement was earlier in patients with bulbar onset (P = 0.007), whereas patients receiving pyridostigmine monotherapy and immunomodulatory therapy had a longer median time of ocular weakness (P < 0.0001). No significant difference was noted between ocular weakness and age of onset, gender, and thymoma. The Cox analysis showed that bulbar onset was a risk factor of ocular weakness (adjusted hazard ratio [HR] 2.65, 95% confidence interval [CI] 1.41-4.99), whereas pyridostigmine monotherapy (adjusted HR 0.28, 95% CI 0.13-0.60) and immunotherapy (adjusted HR 0.09, 95% CI 0.04-0.22) were protective factors. CONCLUSIONS: Eighty-seven percent of patients with MG with nonocular onset developed ocular weakness. Bulbar onset was an independent risk factor for ocular involvement, whereas pyridostigmine and immunotherapy were protective factors.

Nomogram for short-term outcome assessment in AChR subtype generalized myasthenia gravis.

BACKGROUND: An accurate prediction for prognosis can help in guiding the therapeutic options and optimizing the trial design for generalized myasthenia gravis (gMG). We aimed to develop and validate a predictive nomogram to assess the short-term outcome in patients with the anti-acetylcholine receptor (AChR) subtype gMG. METHODS: We retrospectively reviewed 165 patients with AChR subtype gMG who were immunotherapy naïve at the first visit from five tertiary centers in China. The short-term clinical outcome is defined as the achievement of minimal symptom expression (MSE) at 12 months. Of them, 120 gMG patients from Huashan Hospital were enrolled to form a derivation cohort (n = 96) and a temporal validation cohort (n = 24) for the nomogram. Then, this nomogram was externally validated using 45 immunotherapy naïve AChR subtype gMG from the other four hospitals. Multivariate logistic regression was used to screen independent factors and construct the nomogram. RESULTS: MSE was achieved in 70 (72.9%), 20 (83.3%), and 33 (73.3%) patients in the training, temporal validation, and external validation cohort, respectively. The duration ≤ 12 months (p = 0.021), ocular score ≤ 2 (p = 0.006), QMG score > 13 (p = 0.008), and gross motor score ≤ 9 (p = 0.006) were statistically associated with MSE in AChR subtype gMG. The nomogram has good performance in predicting MSE as the concordance indexes are 0.81 (95% CI, 0.72-0.90) in the development cohort, 0.944 (95% CI, 0.83-1.00) in the temporal validation cohort, and 0.773 (95% CI, 0.63-0.92) in the external validation cohort. CONCLUSION: The nomogram achieved an optimal prediction of MSE in AChR subtype gMG patients using the baseline clinical characters.

Neurological manifestations, laboratory and neuroimaging features in HIV-infected patients.

OBJECTIVE: To present detailed information regarding these aspects in Human Immunodeficiency Virus (HIV)-infected patients making an effort to improve the recognition of neurological complications of HIV infection. METHODS: This retrospective study analyzed the clinical manifestations, laboratory and neuroimaging results of HIV-infected patients with neurological complications at Xuanwu hospital, Beijing, China from January 2011 to December 2014, one of top-rated hospitals in Beijing, China. RESULTS: A diverse range of clinical diagnoses was identified, including encephalopathy, meningoencephalitis, peripheral neuropathy, multiple sclerosis, cerebral infarction and lymphoma associated with HIV infection. The mostly observed neurological disorders were motor/sensory deficits in the limbs (75%), cognitive impairments (42%) and fever (33%). Non-specific results of laboratory tests, including elevated erythrocyte sedimentation rate (ESR), cerebrospinal fluid (CSF) protein concentration and IgG, were found. Brain Magnetic Resonance Imaging (MRI) abnormalities displayed a variety of patterns and distributions due to diverse clinical profiles. CONCLUSION: The clinical scenarios of HIV-infected patients are remarkably diverse and complex. Etiological tests would be cardinal to make more definitive diagnosis for HIV-infected patients. Prospective studies with follow-up were needed to bring more accurate information.

A rare complex structural variant of novel intragenic inversion combined with reciprocal translocation t(X;1)(p21.2;p13.3) in Duchenne muscular dystrophy.

Structural variants (SVs) are infrequently observed in Duchenne muscular dystrophy (DMD), a condition mainly marked by deletions and point mutations in the DMD gene. SVs in DMD remain difficult to reliably detect due to the limited SV-detection capacity of conventionally used short-read sequencing technology. Herein, we present a family, a boy and his mother, with clinical signs of muscular dystrophy, elevated creatinine kinase levels, and intellectual disability. A muscle biopsy from the boy showed dystrophin deficiency. Routine molecular techniques failed to detect abnormalities in the DMD gene, however, dystrophin mRNA transcripts analysis revealed an absence of exons 59 to 79. Subsequent long-read whole-genome sequencing identified a rare complex structural variant, a 77 kb novel intragenic inversion, and a balanced translocation t(X;1)(p21.2;p13.3) rearrangement within the DMD gene, expanding the genetic spectrum of dystrophinopathy. Our findings suggested that SVs should be considered in cases where conventional molecular techniques fail to identify pathogenic variants.

Environmental factors affecting the risk of generalization for ocular-onset myasthenia gravis: a nationwide cohort study.

BACKGROUND: The environmental effects on the prognosis of ocular myasthenia gravis (OMG) remain largely unexplored. AIM: To investigate the association between specific environmental factors and the generalization of OMG. DESIGN: The cohort study was conducted in China based on a nationwide multicenter database. METHODS: Adult patients with OMG at onset, who were followed up for at least 2 years until May 2022, were included. We collected data on demographic and clinical factors, as well as environmental factors, including latitude, socioeconomic status (per capita disposable income [PDI] at provincial level and education) and smoking. The study outcome was the time to the development of generalized myasthenia gravis (GMG). Cox models were employed to examine the association between environmental exposures and generalization. Restricted cubic spline was used to model the association of latitude with generalization risk. RESULTS: A total of 1396 participants were included. During a median follow-up of 5.15 (interquartile range [IQR] 3.37-9.03) years, 735 patients developed GMG within a median of 5.69 (IQR 1.10-15.66) years. Latitude of 20-50°N showed a U-shaped relation with generalization risk, with the lowest risk at around 30°N; both higher and lower latitudes were associated with the increased risk (P for non-linearity <0.001). Living in areas with lower PDI had 1.28-2.11 times higher risk of generalization. No significant association was observed with education or smoking. CONCLUSIONS: Latitude and provincial-level PDI were associated with the generalization of OMG in China. Further studies are warranted to validate our findings and investigate their potential applications in clinical practice and health policy.

Posterior reversible encephalopathy syndrome in a leber hereditary optic neuropathy patient with mitochondrial DNA 11778G>A point mutation.

Leber hereditary optic neuropathy (LHON) is a maternally inherited mitochondrial disorder that primarily affects the optic nerve. We report a case of reduced visual acuity secondary to optic atrophy in a 13-year-old boy. Transient seizures developed subsequently. Serial magnetic resonance imaging of the brain showed posterior reversible encephalopathy syndrome. Ragged red fibers were not detected on skeletal muscle biopsy. A 11778G>A mitochondrial DNA point mutation was identified in the lymphocytes isolated from peripheral blood. His younger brother was a carrier with the same mutation. The presentation of this case is unusual documenting LHON in association with PRES.

[Clinical and imaging features and genetic analysis of a case with adult-onset Krabbe disease].

OBJECTIVE: To investigate clinical and imaging features of a patient with adult-onset Krabbe disease and to detect the underlying genetic mutations. METHODS: Clinical and cranial MRI features of the patient were analyzed. Pathogenesis, clinical manifestation, cranial MRI features and diagnostic criteria for the disease were discussed. RESULTS: The patient had presented asymmetric limb weakness and difficulty in walking. Electromyography suggested peripheral nerve demyelination. Cranial MRI showed increased signal intensity in white matter with involvement of the corticospinal tracts. Screening of GALC gene mutation has found the patient to be heterozygous for T1685C (Ile562Thr) and homozygous for A1921G (Thr641Ala), both of which were considered to be polymorphisms. In addition, he was heterozygous for G136T (Asp46Tyr), which had not been described previously. CONCLUSION: Clinical manifestations of adult-onset Krabbe disease may be atypical. Cranial MRI and galactocerebroside activity assay should be carried out for patients featuring chronic progressive corticospinal tract injury. An Asp46Tyr mutation probably underlies the disease in the current case.

A Case Study and Literature Review of the Diagnosis of Danon Disease in Patients Presenting Only with Severe Cardiac Symptoms.

The clinical manifestations of Danon disease, which result from the primary deficiency of the lysosome-associated membrane protein 2 gene, include cardiomyopathy, skeletal myopathy, and different degrees of intellectual disability that vary greatly among patients. The present study reports on two cases of Danon disease in two patients who only presented cardiac symptoms. Cardiac symptoms usually occur in adolescence and during a patient's twenties, and most patients die from heart failure. However, the lab results from these cases suggested that other systems were involved, despite no other clinical symptoms. Significantly, the two patients had elevated serum cardiac troponin I, which often manifests in the acute cardiac phase, especially in severely affected patients with rapidly fatal outcomes. Danon disease is a multi-system involvement disease. Therefore, clinicians must be aware of its complexity when evaluating newly diagnosed patients due to its vastly different clinical course and prognosis and the importance of multidisciplinary management.

Comparison between mono-tacrolimus and mono-glucocorticoid in the treatment of myasthenia gravis.

OBJECTIVE: Use of tacrolimus in mild to moderate myasthenia gravis (MG) is generally limited to glucocorticoid-refractory cases; the advantage of mono-tacrolimus over mono-glucocorticoids is unknown. METHODS: We included mild to moderate MG patients treated with mono-tacrolimus (mono-TAC) or mono-glucocorticoids (mono-GC). The correlation between the immunotherapy options and the treatment efficacy and side effects were examined in 1:1 propensity-score matching. The main outcome was time to minimal manifestations status or better (MMS or better). Secondary outcomes include time to relapse, the mean changes in Myasthenia Gravis-specific Activities of Daily Living (MG-ADL) scores and the rate of adverse events. RESULTS: Baseline characteristics showed no difference between matched groups (49 matched pairs). There were no differences in median time to MMS or better between the mono-TAC group and mono-GC group (5.1 vs. 2.8 months: unadjusted hazard ratio [HR], 0.73; 95% CI, 0.46-1.16; p = 0.180), as well as in median time to relapse (data unavailable for the mono-TAC group since 44 of 49 [89.8%] participants remained in MMS or better; 39.7 months in mono-GC group: unadjusted HR, 0.67; 95% CI, 0.23-1.97; p = 0.464). Changes in MG-ADL scores between the two groups were similar (mean differences, 0.3; 95% CI, -0.4 to 1.0; p = 0.462). The rate of adverse events was lower in the mono-TAC group compared to the mono-GC group (24.5% vs. 55.1%, p = 0.002). INTERPRETATION: Mono-tacrolimus performs superior tolerability with non-inferior efficacy compared to mono-glucocorticoids in mild to moderate myasthenia gravis patients who refuse or have a contraindication to glucocorticoids.

Mortality of myasthenia gravis: a national population-based study in China.

OBJECTIVE: As a potentially life-threatening condition, myasthenia gravis (MG) has limited epidemiological studies on mortality. We aim to provide demographic distribution, geographical variation, and temporal trend of MG-related mortality in China. METHODS: The national population-based analysis was conducted based on records derived from the National Mortality Surveillance System of China. All deaths related to MG were identified from 2013 to 2020, and MG-related mortality was evaluated by sex, age, location, and year. RESULTS: A total of 4224 deaths were related to MG during 2013-2020, and the median age at death of MG was 59.45 years, significantly lower than that in the general population (75.47 years, P < 0.05). In 2020, the age-standardized mortality rate of MG was 1.86 per million people and markedly higher in males than in females (2.37 vs. 1.31 per million). The mortality rate per million was lower than 1 in young children, peaking at 2.83 only in males (vs. 0.36 in females) aged 10-19 years, and substantially increased with age, reaching the highest rate of 13.31 for males and 10.58 for females aged 80 years and older. Geographical disparity across China was observed with the highest age-standardized mortality rate in Southwest (2.53 per million). From 2013 to 2020, MG-related mortality rate showed an increasing trend with the average annual percentage change of 3.5% (95% CI, 1.4-5.6). The notable increases occurred in age 10-19 years and over 70 years. INTERPRETATION: In China, MG-related mortality was notably high among adolescent males and the elderly. The increasing death burden due to MG highlight challenges to disease management.

Short-term outcome prediction for myasthenia gravis: an explainable machine learning model.

Background: Myasthenia gravis (MG) is an autoimmune disease characterized by muscle weakness and fatigability. The fluctuating nature of the disease course impedes the clinical management. Objective: The purpose of the study was to establish and validate a machine learning (ML)-based model for predicting the short-term clinical outcome in MG patients with different antibody types. Methods: We studied 890 MG patients who had regular follow-ups at 11 tertiary centers in China from 1 January 2015 to 31 July 2021 (653 patients for derivation and 237 for validation). The short-term outcome was the modified post-intervention status (PIS) at a 6-month visit. A two-step variable screening was used to determine the factors for model construction and 14 ML algorithms were used for model optimisation. Results: The derivation cohort included 653 patients from Huashan hospital [age 44.24 (17.22) years, female 57.6%, generalized MG 73.5%], and the validation cohort included 237 patients from 10 independent centers [age 44.24 (17.22) years, female 55.0%, generalized MG 81.2%]. The ML model identified patients who were improved with an area under the receiver operating characteristic curve (AUC) of 0.91 [0.89-0.93], 'Unchanged' 0.89 [0.87-0.91], and 'Worse' 0.89 [0.85-0.92] in the derivation cohort, whereas identified patients who were improved with an AUC of 0.84 [0.79-0.89], 'Unchanged' 0.74 [0.67-0.82], and 'Worse' 0.79 [0.70-0.88] in the validation cohort. Both datasets presented a good calibration ability by fitting the expectation slopes. The model is finally explained by 25 simple predictors and transferred to a feasible web tool for an initial assessment. Conclusion: The explainable, ML-based predictive model can aid in forecasting the short-term outcome for MG with good accuracy in clinical practice.

[Detection for trinucleotide repeats in myotonic dystrophy type 1].

OBJECTIVE: To establish an efficient method which can be easily used for detecting CTG trinucleotide repeats in myotonic dystrophy type 1 (DM1). METHODS: Tri-primer polymerase chain reaction (TP-PCR) combined with electropherogram was used to detect CTG repeats in the 3'-untranslated region of DMPK gene. Twenty non-related DM1 patients and 24 healthy controls were selected. RESULTS: All patients were found to have carried pathologic alleles containing more than 100 CTG repeats, while the healthy controls have carried 5-37 CTG repeats. CONCLUSION: TP-PCR combined with electropherograms may provide a highly sensitive, specific and accurate method which is less time-consuming and easier to perform for the detection of pathologic alleles in DM1 patients.

A Randomized Open-Labeled Trial of Methotrexate as a Steroid-Sparing Agent for Patients With Generalized Myasthenia Gravis.

Background and Purpose: Two clinical trials assessing the steroid-sparing effect of methotrexate (MTX) yielded conflicting results. Our objective was to investigate whether MTX would show a steroid-sparing effect in the treatment of generalized myasthenia gravis (MG) patients who fitted Myasthenia Gravis Foundation of America (MGFA) Class II and Class III. Methods: We performed an 18-month prospective, randomized, open-labeled trial of prednisone combined with MTX 10 mg orally every week versus prednisone alone in 40 recently diagnosed MG patients of MGFA Class II and Class III between July 2014 and July 2018. The primary endpoint was the prednisone area under the dose-time curve (AUDTC) from months 3 to 18. Secondary endpoints included changes of the Quantitative Myasthenia Gravis Score (QMG), the Myasthenia Gravis Activity of Daily Living Score (MG-ADL), initial time of prednisone reduction, the median prednisone daily dose in each month, adverse events, and treatment failures in each group. Results: Forty participants were included; among those, 5 individuals withdrew. A total of 35 participants completed 18 months of follow-up (18 in prednisone+MTX, 17 in prednisone group). Combined use of MTX reduced the month 3-18 prednisone AUDTC (prednisone+MTX 5,663.44 ± 1,678.08 mg, prednisone 6,683.94 ± 678.08 mg, p = 0.03, 95% confidence interval -1916.01 to -124.98). The initial times of prednisone reduction were 4.34 ± 1.44 months in the prednisone+MTX group and 5.56 ± 2.05 months in the prednisone group (p = 0.04, 95% CI -2.41 to -0.03). The median daily prednisone dose was significantly lower in the prednisone+MTX group at month 6 and months 9-18. No significant differences were found in QMG and MG-ADL scores between the two groups. No serious drug-related adverse events were observed in both groups. Conclusions: This study provides evidence that MTX has the steroid-sparing ability in generalized MG patients of MGFA Class II and Class III. Clinical Trial Registration: http://www.chictr.org.cn/showproj.aspx?proj=10563 identifier ChiCTR-IPR-15006081.