Early rituximab treatment reduces long-term disability in aquaporin-4 antibody-positive neuromyelitis optica spectrum.

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) causes relapsing inflammatory attacks in the central nervous system, leading to disability. As rituximab, a B-lymphocyte-depleting monoclonal antibody, is an effective in preventing NMOSD relapses, we hypothesised that earlier initiation of rituximab can also reduce long-term disability of patients with NMOSD. METHODS: This multicentre retrospective study involving 19 South Korean referral centres included patients with NMOSD with aquaporin-4 antibodies receiving rituximab treatment. Factors associated with the long-term Expanded Disability Status Scale (EDSS) were assessed using multivariable regression analysis. RESULTS: In total, 145 patients with rituximab treatment (mean age of onset, 39.5 years; 88.3% female; 98.6% on immunosuppressants/oral steroids before rituximab treatment; mean disease duration of 121 months) were included. Multivariable analysis revealed that the EDSS at the last follow-up was associated with time to rituximab initiation (interval from first symptom onset to initiation of rituximab treatment). EDSS at the last follow-up was also associated with maximum EDSS before rituximab treatment. In subgroup analysis, the time to initiation of rituximab was associated with EDSS at last follow-up in patients aged less than 50 years, female and those with a maximum EDSS score ≥6 before rituximab treatment. CONCLUSIONS: Earlier initiation of rituximab treatment may prevent long-term disability worsening in patients with NMOSD, especially among those with early to middle-age onset, female sex and severe attacks.

Brighter spotty lesions on spinal MRI help differentiate AQP4 antibody-positive NMOSD from MOGAD.

In a large acute myelitis cohort, we aimed to determine whether brighter spotty lesions (BSLs)-using the refined terminology-on spinal magnetic resonance imaging (MRI) help distinguish aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) from myelin oligodendrocyte glycoprotein antibody disease (MOGAD). An experienced neuro-radiologist and two neurologists independently analyzed 133 spinal MRI scans (65 from MOGAD and 68 from AQP4-NMOSD) acquired within 1 month of attacks. BSLs were observed in 18 of 61 (30%) participants with AQP4-NMOSD, while none of 49 participants with MOGAD showed BSL (p < 0.001). BSL during the acute phase would be useful to differentiate AQP4-NMOSD from MOGAD.

Recurrence of clinical events at the same anatomical location in patients with MOG antibody-associated disease.

OBJECTIVES: Likelihood of clinical events occurring within the same anatomical location in patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) was retrospectively investigated. METHODS: A total of 236 clinical events in 90 patients with MOGAD from nine referral hospitals were analyzed via logistic regression, and odds ratios (ORs) were calculated. Anatomical lesion location was divided into four groups; optic nerve, spinal cord, cerebral hemisphere, and brainstem/cerebellum. RESULTS: At all locations, there was an increased likelihood of a second attack occurring at the same location as the initial event (cerebral hemisphere OR = 22.14, brainstem/cerebellum OR = 18.4, spinal cord OR = 9.1, and optic nerve OR = 7.8). There was an increased likelihood of a third attack occurring at the same location as the initial event in the optic nerve (OR = 14.9), cerebral hemisphere (OR = 11.7), and spinal cord (OR = 6.7). There were positive trends toward a third clinical event occurring at the same location as the first and/or second events if the event was in the optic nerve (OR = 13.5), cerebral hemisphere (OR = 6.9), or spinal cord (OR = 5.7). CONCLUSIONS: The current study suggests that clinical relapses of MOGAD during early stage tend to recur at the same anatomical locations in the central nervous system.

Comparison of MOG and AQP4 antibody seroprevalence in Korean adults with inflammatory demyelinating CNS diseases.

We aimed to compare seroprevalence of anti-myelin oligodendrocyte glycoprotein (MOG) and anti-aquaporin-4 (AQP4) antibodies in Korean adults with inflammatory demyelinating diseases (IDDs) of the central nervous system (CNS), based on a multicenter nationwide database. Sera were analyzed using a live cell-based assay for MOG and AQP4 antibodies. Of 586 Korean adults with IDDs of the CNS, 36 (6.1%) and 185 (31.6%) tested positive for MOG and AQP4 antibodies, respectively. No participant showed double positivity. Seroprevalence of MOG antibodies was about five times lower than that of AQP4 antibodies in a large cohort of Korean adults with IDDs of the CNS.

Serum FAM19A5 in neuromyelitis optica spectrum disorders: Can it be a new biomarker representing clinical status?

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) targets astrocytes and elevates the levels of astrocyte-injury markers during attacks. FAM19A5, involved in reactive gliosis, is secreted by reactive astrocytes following central nervous system (CNS) damage. OBJECTIVE: To investigate the significance of serum FAM19A5 in patients with NMOSD. METHODS: We collected clinical data and sera of 199 patients from 11 hospitals over 21 months. FAM19A5 levels were compared among three groups: NMOSD with positive anti-aquaporin-4 antibody (NMOSD-AQP4), other CNS demyelinating disease, and healthy controls. RESULTS: The median serum FAM19A5 level was higher in the NMOSD-AQP4 (4.90 ng/mL (3.95, 5.79)) than in the other CNS demyelinating (2.35 ng/mL (1.83, 4.07), p < 0.001) or healthy control (1.02 ng/mL (0.92, 1.14), p < 0.001) groups. There were significant differences in the median serum FAM19A5 levels between the attack and remission periods (5.89 ng/mL (5.18, 6.98); 4.40 ng/mL (2.72, 5.13), p < 0.001) in the NMOSD-AQP4 group. Sampling during an attack (p < 0.001) and number of past attacks (p = 0.010) were independently associated with increased serum FAM19A5. CONCLUSION: Serum FAM19A5 was higher in patients with NMOSD-AQP4 and correlated with clinical characteristics. Thus, serum FAM19A5 may be a novel clinical biomarker for NMOSD-AQP4.

Evaluation of brain lesion distribution criteria at disease onset in differentiating MS from NMOSD and MOG-IgG-associated encephalomyelitis.

OBJECTIVES: We aimed to evaluate the utility of the recently described brain lesion distribution criteria to differentiate multiple sclerosis (MS) from aquaporin-4 immunoglobulin G-positive neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein immunoglobulin G-associated encephalomyelitis (MOG-EM) at disease onset in an Asian cohort. METHODS: A total of 214 patients who fulfilled the published criteria for MS, NMOSD, or MOG-EM and underwent brain magnetic resonance imaging (MRI) within 3 months of disease onset were enrolled. The brain lesion distribution criteria were defined as the presence of a lesion adjacent to the body of the lateral ventricle and in the inferior temporal lobe, or an S-shaped U-fiber lesion, or a Dawson's finger-type lesion. RESULTS: Brain lesions were identified in the initial MRI scans of 166/214 patients. The distribution criteria were applied to these scans (MS ( n = 94), NMOSD ( n = 64), and MOG-EM ( n = 8)). The sensitivity, specificity, and positive and negative predictive values of the criteria for MS versus NMOSD were 79.8%, 87.5%, 90.4%, and 74.7%, and for MS versus MOG-EM these were 79.8%, 100%, 100%, and 29.6%, respectively. CONCLUSION: These findings suggest that the brain lesion distribution criteria are helpful in distinguishing MS from NMOSD and MOG-EM in an Asian population, even at disease onset.

Application of the 2017 McDonald diagnostic criteria for multiple sclerosis in Korean patients with clinically isolated syndrome.

OBJECTIVES: To evaluate the validity of the revised 2017 McDonald criteria for multiple sclerosis (MS) compared with the 2010 McDonald criteria to predict conversion to clinically definite multiple sclerosis (CDMS) in patients with clinically isolated syndrome (CIS). METHODS: A total of 163 patients from seven referral hospitals in Korea, who experienced a first clinical event suggestive of MS between 2006 and 2017, were enrolled. Patients were stratified into two groups according to outcome at the last visit: CDMS converters who experienced a second clinical event and non-converters. RESULTS: Of the 163 patients with a mean follow-up of 63 months, 60% converted to CDMS. The sensitivity, specificity, positive and negative predictive values and accuracy were, respectively, 88.8%, 43.1%, 70.2%, 71.8% and 70.6% for the 2017 McDonald criteria and 53.1%, 69.2%, 72.2%, 49.5% and 59.5% for the 2010 McDonald criteria. After exclusion of 82 patients who received disease-modifying agents before the second attack, the specificity of the 2017 and 2010 McDonald criteria increased to 85.0% and 95.0%, but sensitivity decreased to 83.6% and 47.5%, respectively. CONCLUSION: The 2017 McDonald criteria afforded higher sensitivity and accuracy but lower specificity compared with the 2010 McDonald criteria for prediction of conversion to CDMS in Korean CIS patients.

Evaluation of 2016 MAGNIMS MRI criteria for dissemination in space in patients with a clinically isolated syndrome.

OBJECTIVES: We compared validity of 2010 McDonald and newly proposed 2016 Magnetic Resonance Imaging in Multiple Sclerosis (MAGNIMS) criteria for dissemination in space (DIS) in predicting the conversion to clinically definite multiple sclerosis (CDMS) in patients with clinically isolated syndrome (CIS). METHODS: Between 2006 and 2016, we enrolled 170 patients who had a first clinical event suggestive of multiple sclerosis (MS) from seven referral hospitals in Korea. Patients were classified into two groups based on the main outcome at the last follow-up: CDMS converters, who experienced a second attack, and non-converters. RESULTS: Of 170 patients with mean follow-up duration of 54 months, 51% converted to CDMS. The sensitivity, specificity, accuracy, and positive and negative predictive values of 2010 McDonald criteria were 70.9%, 63.1%, 67.1%, 66.3%, and 67.9%, and those for 2016 MAGNIMS criteria were 88.4%, 46.4%, 67.7%, 62.8%, and 79.6%, respectively. When we excluded 80 patients who underwent disease-modifying therapy before the second clinical event, the specificity increased to 92.3% and 84.6%, but the sensitivity decreased to 58.8% and 82.4% for 2010 McDonald and 2016 MAGNIMS criteria, respectively. CONCLUSION: 2016 MAGNIMS magnetic resonance imaging (MRI) criteria for DIS showed higher sensitivity but lower specificity than 2010 McDonald criteria in predicting conversion to CDMS in CIS patients.

Short segment myelitis as a first manifestation of neuromyelitis optica spectrum disorders.

BACKGROUND: Some patients with neuromyelitis optica spectrum disorders (NMOSD) present with spinal cord lesions extending fewer than three vertebral segments (short transverse myelitis, STM), hindering an early diagnosis. OBJECTIVE: We investigated the frequency and imaging characteristics of STM lesions in patients presenting with myelitis as an initial manifestation of NMOSD. METHODS: Patients seen at three referral hospitals in Korea between June 2005 and March 2015 who met the following inclusion criteria were recruited for review: seropositivity for aquaporin-4 antibody, initial presentation with myelitis and spinal cord magnetic resonance imaging (MRI) performed within 1 month of initial myelitis onset. RESULTS: Of the 76 enrolled patients, 65 (85.5%) collectively had 69 longitudinally extensive transverse myelitis lesions, while the remaining 11 (14.5%) had a total of 15 STM lesions. Of the 15 STM lesions, 5 spanned 2.5 vertebral segments, 6 were continuous over two segments, 3 showed a length of 1.5 segments and 1 was confined to a single segment. On axial imaging, all of the STM lesions involved the central grey matter. CONCLUSION: These MRI findings suggested that STM does not preclude the possibility of an NMOSD diagnosis.

Clinical characteristics of late-onset neuromyelitis optica spectrum disorder: A multicenter retrospective study in Korea.

BACKGROUND: There are currently few studies regarding late-onset neuromyelitis optica spectrum disorder (LO-NMOSD). OBJECTIVE: We aimed to describe the characteristic features of patients with LO-NMOSD in Korea. METHODS: Anti-aquaporin-4 antibody-positive patients with neuromyelitis optica spectrum disorder (NMOSD) from nine tertiary hospitals were reviewed retrospectively. The patients were divided into two groups based on age of onset: LO-NMOSD (⩾50 years of age at onset) versus early-onset neuromyelitis optica spectrum disorder (EO-NMOSD) (<50 years of age at onset). Clinical, laboratory, and magnetic resonance imaging (MRI) parameters were investigated. RESULTS: Among a total of 147 patients (125 female; age of onset, 39.4 ± 15.2 years), 45 patients (30.6%) had an age of onset of more than 50 years. Compared to patients with EO-NMOSD, patients with LO-NMOSD had more frequent isolated spinal cord involvement at onset (64.4% vs 37.2%, p = 0.002), less frequent involvement of the optic nerve (40.0% vs 67.7%, p = 0.002), and less frequent brain MRI lesions (31.1% vs 50.0%, p = 0.034). Furthermore, there was a significant positive correlation between age of onset and Expanded Disability Status Scale (EDSS) score at last follow-up ( r = 0.246, p = 0.003). CONCLUSION: Age of onset could be an important predictor of lesion location and clinical course of patients with NMOSD.

Idiopathic aquaporin-4 antibody negative longitudinally extensive transverse myelitis.

BACKGROUND: Longitudinally extensive transverse myelitis (LETM) is a characteristic manifestation of neuromyelitis optica (NMO). However, not all patients with LETM are positive for aquaporin-4 (AQP4) antibodies. We evaluated the characteristics of idiopathic isolated LETM negative for AQP4 antibodies. METHODS: From the National Cancer Center registry of inflammatory diseases of the central nervous system, patients with LETM as an initial manifestation and follow-up for at least two years were enrolled. Their medical records and MRIs were reviewed retrospectively. AQP4 antibody was confirmed by three different validated methods at least three times. Cerebrospinal fluid (CSF) glial fibrillary acidic protein (GFAP) levels were measured to investigate astrocyte damage. RESULTS: Among 108 patients with first-ever LETM, 55 were positive for AQP4 antibodies (P-LETM) and 53 were consistently negative. Of them, seven were later diagnosed with seronegative NMO, and four were positive for MOG antibodies. The remaining 42 patients (N-LETM) showed several features distinct from P-LETM: male predominance, older age of onset, milder clinical presentation, spinal cord confinement and absence of combined autoimmunity. CSF GFAP levels were not increased in N-LETM but were markedly elevated in P-LETM. CONCLUSIONS: Idiopathic isolated N-LETM is not that rare among first-ever LETM, and has many features distinct from P-LETM where astrocytic damage is evident.

The usefulness of brain MRI at onset in the differentiation of multiple sclerosis and seropositive neuromyelitis optica spectrum disorders.

BACKGROUND: Although neuromyelitis optica (NMO) is a central nervous system (CNS) autoimmune disease distinct from multiple sclerosis (MS). NMO and NMO spectrum disorder (NMOSD) sometimes show asymptomatic lesions on brain magnetic resonance imaging (MRI) at onset, and even present with symptomatic brain involvement. OBJECTIVES: We investigated whether brain MRI at onset can be helpful for the differentiation of MS and NMOSD. METHODS: We retrospectively analyzed initial brain MRIs, performed within three months of onset, in patients with MS (n = 51) and anti-aquaporin4-antibody-positive patients with NMOSD (n = 67). RESULTS: NMOSD patients met the Paty (37%) and Barkhof (13%) criteria, and the criteria of the European Magnetic Imaging in MS (MAGNIMS) study group (9%), for MS. Ovoid lesions perpendicular to the lateral ventricle, isolated juxtacortical lesions in U-fibers and isolated ovoid/round cortical lesions were found only in MS patients, whereas longitudinal corticospinal tract lesions, extensive hemispheric lesions, periependymal lesions surrounding the lateral ventricle and cervicomedullary lesions were found only in NMOSD patients. CONCLUSIONS: Our study suggests that it is difficult to differentiate MS from NMOSD by the fulfillment of the MRI criteria for MS on brain MRI at onset; however, the characteristic morphology of brain lesions is highly useful for the early differentiation of the two disorders.

Evaluation of McDonald MRI criteria for dissemination in space in Korean patients with clinically isolated syndromes.

We investigated the validity of the 2005 and 2010 McDonald magnetic resonance imaging (MRI) criteria for dissemination in space (DIS) to predict the conversion of clinically definite multiple sclerosis (CDMS) in 94 Korean patients with clinically isolated syndromes (CIS). The sensitivity, specificity, accuracy, positive and negative predictive values of the 2005, 2010 McDonald DIS criteria were comparable to those observed in the Caucasian population. This finding suggests that after careful exclusion of alternative explanations, particularly neuromyelitis optica (NMO) and NMO spectrum disorder (NMOSD), both the 2005 and 2010 McDonald DIS criteria are also useful to predict conversion to CDMS in Korean patients with CIS.

Therapeutic Outcomes and Electrophysiological Biomarkers in Anti-Myelin-Associated Glycoprotein Neuropathy: A Multicenter Cohort Study in South Korea.

BACKGROUND AND PURPOSE: Unlike other immune-mediated neuropathies, anti-myelin-associated glycoprotein (MAG) neuropathy is often refractory to immunotherapy. It is necessary to compare the relative efficacies of various immunotherapies and develop objective biomarkers in order to optimize its clinical management. METHODS: This study recruited 91 patients with high anti-MAG antibody titers from 7 tertiary hospitals in South Korea. We analyzed the baseline characteristics, therapeutic outcomes, and nerve conduction study (NCS) findings of 68 patients and excluded 23 false positive cases. RESULTS: The rate of positive responses to treatment was highest using zanubrutinib (50%) and rituximab (36.4%), followed by corticosteroids (16.7%), immunosuppressants (9.5%), intravenous immunoglobulin (5%), and plasma exchange (0%). Disability and weakness were significantly associated with multiple NCS parameters at the time of diagnosis, especially distal compound muscle action potential (CMAP) amplitudes. Moreover, the longitudinal trajectory of the average CMAP amplitudes paralleled the clinical courses, with a 16.2 percentile decrease as an optimal cutoff for predicting a clinical exacerbation (area under the receiver operating characteristic curve=0.792). CONCLUSIONS: Our study supports the use of NCS as an objective marker for estimating disease burden and tracking clinical changes in patients with anti-MAG neuropathy. We have described the beneficial effects of rituximab and a new drug, zanubrutinib, compared with conventional immunotherapies.

Potential prognostic value of rheumatoid factor in anti-aquaporin 4-immunoglobin G-positive neuromyelitis optica spectrum disorders.

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is the central nervous system demyelinating disease differentiated from multiple sclerosis by the presence of anti-aquaporin 4-antibody (AQP4-ab), which is sometimes accompanied by non-organ-specific autoantibodies. METHODS: We prospectively collected clinical information and profiles of non-organ-specific autoantibodies such as fluorescent antinuclear (FANA), anti-Sjögren's syndrome A (SSA)/Ro, anti-SS B (SSB)/La, anti-neutrophil cytoplasmatic (ANCA), lupus anticoagulant (LA), anti-cardiolipin (ACA), anti-double-stranded DNA (dsDNA), rheumatoid factor (RF), anti-thyroperoxidase, and anti-thyroglobulin antibodies in patients with NMOSD. Clinical characteristics and laboratory findings of patients with NMOSD with or without autoantibodies were analyzed. Cox proportional hazard models were used to identify independent risk factors predicting high disability in patients with NMOSD. RESULTS: A total of 158 patients with NMOSD (Female: Male = 146:12; age, 36.11 ± 14.7) were included. FANA was observed most frequently (33.3 %), followed by anti-SSA (28.6 %), anti-SSB (10.0 %), RF (8.5 %), anti-dsDNA (7.0 %), LA (4.7 %), ACA (4.8 %), and ANCA (2.4 %). High disability (Expanded Disability Status Scale (EDSS) score ≥ 6) was observed more frequently in patients with RF (45.5 %) than in those without RF (14.5 %) (p = 0.02). RF was a significant predictive factor for the high disability (hazard ratio [HR], 3.763; 95 % confidence interval [CI], 1.086-13.038; p = 0.037), age at onset (HR, 1.093; 95 % CI, 1.05-1.14; p ≤0.001), and annual relapse rate (ARR) (HR, 4.212; 95 % CI, 1.867-9.503; p = 0.001). CONCLUSION: Organ-specific and non-organ-specific autoantibodies are frequently observed in Korean patients with AQP4-ab-positive NMOSD. RF may be an independent predictor of high disability, along with age at onset and ARR.

Differentiated pattern of complement system activation between MOG-IgG-associated disease and AQP4-IgG-positive neuromyelitis optica spectrum disorder.

Background: Myelin oligodendrocyte glycoprotein antibody (MOG) immunoglobulin G (IgG)-associated disease (MOGAD) has clinical and pathophysiological features that are similar to but distinct from those of aquaporin-4 antibody (AQP4-IgG)-positive neuromyelitis optica spectrum disorders (AQP4-NMOSD). MOG-IgG and AQP4-IgG, mostly of the IgG1 subtype, can both activate the complement system. Therefore, we investigated whether the levels of serum complement components, regulators, and activation products differ between MOGAD and AQP4-NMOSD, and if complement analytes can be utilized to differentiate between these diseases. Methods: The sera of patients with MOGAD (from during an attack and remission; N=19 and N=9, respectively) and AQP4-NMOSD (N=35 and N=17), and healthy controls (N=38) were analyzed for C1q-binding circulating immune complex (CIC-C1q), C1 inhibitor (C1-INH), factor H (FH), C3, iC3b, and soluble terminal complement complex (sC5b-9). Results: In attack samples, the levels of C1-INH, FH, and iC3b were higher in the MOGAD group than in the NMOSD group (all, p<0.001), while the level of sC5b-9 was increased only in the NMOSD group. In MOGAD, there were no differences in the concentrations of complement analytes based on disease status. However, within AQP4-NMOSD, remission samples indicated a higher C1-INH level than attack samples (p=0.003). Notably, AQP4-NMOSD patients on medications during attack showed lower levels of iC3b (p<0.001) and higher levels of C3 (p=0.008), C1-INH (p=0.004), and sC5b-9 (p<0.001) compared to those not on medication. Among patients not on medication at the time of attack sampling, serum MOG-IgG cell-based assay (CBA) score had a positive correlation with iC3b and C1-INH levels (rho=0.764 and p=0.010, and rho=0.629 and p=0.049, respectively), and AQP4-IgG CBA score had a positive correlation with C1-INH level (rho=0.836, p=0.003). Conclusions: This study indicates a higher prominence of complement pathway activation and subsequent C3 degradation in MOGAD compared to AQP4-NMOSD. On the other hand, the production of terminal complement complexes (TCC) was found to be more substantial in AQP4-NMOSD than in MOGAD. These findings suggest a strong regulation of the complement system, implying its potential involvement in the pathogenesis of MOGAD through mechanisms that extend beyond TCC formation.

Clinical characteristics and outcome of multiple sclerosis in Korea: does multiple sclerosis in Korea really differ from that in the Caucasian populations?

BACKGROUND: Multiple sclerosis (MS) in Asia is thought to have different clinical characteristics from MS in Western countries; however, previous studies in Asia were performed without properly differentiating neuromyelitis optica (NMO) from MS. OBJECTIVES: To evaluate the clinical characteristics of MS in Korea after careful exclusion of potential explanations other than MS, particularly NMO spectrum disorder (NMOSD). METHODS: This study is a retrospective review of consecutive MS patients attending five referral hospitals in Korea. All patients' MS diagnoses were re-evaluated. RESULTS: Of the 105 patients, 70 were female and 35 were male. The mean age of onset was 30.4 years and the mean disease duration was 5.4 years. On initial magnetic resonance imaging (MRI), 58% and 64% fulfilled the criteria for dissemination in space for the 2005 and 2010 McDonald criteria, respectively. Spinal cord lesions were observed in 78% of patients, primarily present as multiple small lesions with a mean length of 0.9 vertebral segments. The median time from disease onset to an Expanded Disability Status Scale 6 was 20 years. CONCLUSIONS: After careful exclusion of NMOSD, we found that the clinical pattern of MS in Korea does not fundamentally differ from that seen in Western countries.

Limb-girdle myasthenia with tubular aggregates associated with novel GFPT1 mutations.

INTRODUCTION: Limb-girdle myasthenia with tubular aggregates (LGM with TAs) is a subtype of congenital myasthenic syndrome caused by recessive mutations of glutamine-fructose-6-phosphate transaminase 1 (GFPT1). METHODS: Clinical and neurophysiological assessment was made in a Korean boy who had proximal limb muscle weakness. Findings suggested a diagnosis of congenital myasthenic syndrome. RESULTS: Muscle biopsy disclosed numerous TAs in muscle fibers, and DNA sequence analysis disclosed 2 novel missense mutations (p.E256Q and p.M499T) in GFPT1. Treatment with oral cholinesterase inhibitors produced a dramatic improvement in muscle strength. CONCLUSIONS: GFPT1 is the key enzyme in the hexosamine biosynthesis pathway, and mutations in GFPT1 cause defective glycosylation in the proteins of the neuromuscular junction. Identification of LGM with TAs among patients with congenital myasthenic syndrome is important because treatment with cholinesterase inhibitors can produce symptomatic improvement.

Safety and Temporal Pattern of the Lymphocyte Count During Fingolimod Therapy in Patients With Multiple Sclerosis: Real-World Korean Experience.

BACKGROUND AND PURPOSE: Fingolimod (FTY) inhibits lymphocyte egress from lymphoid organs to cause lymphopenia, but the clinical implications of FTY-induced lymphopenia are not fully understood. We aimed to determine the frequency and severity of lymphopenia during FTY treatment among Korean patients with multiple sclerosis (MS), and its association with infections. METHODS: We retrospectively reviewed the medical records of patients with MS treated using FTY from 12 referral centers in South Korea between March 2013 and June 2021. Patients were classified according to their nadir absolute lymphocyte count (ALC) during treatment: grade 1, 800-999/µL; grade 2, 500-799/µL; grade 3, 200-499/µL; and grade 4, <200/µL. RESULTS: FTY treatment was administered to 69 patients with a median duration of 18 months (range=1-169 months), with 11 patients being treated for ≥7 years. During FTY treatment, mean ALCs were reduced after the first month (653.0±268.9/µL, mean±standard deviation) (p<0.0001) and remained low during treatment lasting up to 84 months. During follow-up, 41 (59.4%) and 7 (10.1%) patients developed grade-3 and grade-4 lymphopenia, respectively. No significant difference was found in age at FTY initiation, sex, baseline ALC, body mass index, or prior disease-modifying treatment between patients with and without grade-4 lymphopenia. Infections were observed in 11 (15.9%) patients, and the frequencies of patients with and without grade-4 lymphopenia were similar. CONCLUSIONS: FTY treatment induced grade-4 lymphopenia in 10% of South Korean patients with MS, but did not appear to be associated with an increased infection risk.

Validation of the Korean Version of the 12-Item Multiple Sclerosis Walking Scale and Application to Neuromyelitis Optica Spectrum Disorder.

BACKGROUND AND PURPOSE: Gait problems are a primary complaint in patients with multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). The 12-item Multiple Sclerosis Walking Scale (MSWS-12) is a patient-reported measure assessing the impact of MS on the walking ability. We aimed to adapt and validate the Korean version of the MSWS-12 for the Korean population with MS and NMOSD. METHODS: Thirty-four MS and 35 NMOSD patients were recruited. The MSWS-12 questionnaire was translated into the Korean language and evaluated for its validity and reliability in these patients. RESULTS: The MS and NMOSD patients had mean ages of 35.9 and 42.1 years, respectively, median disease durations of 5.6 and 7.2 years, median Expanded Disability Status Scale (EDSS) scores of 2.75 (range, 0-6.5) and 3.5 (range, 0-7.5), and median baseline MSWS-12 total scores of 25 [interquartile range (IQR), 2.60-53.65] and 25 (IQR, 7.29-50.00). The baseline MSWS-12 total score in the patients with MS showed strong correlations with scores for the EDSS, timed 25-foot walk (T25FW), Multiple Sclerosis Impact Scale-29 (MSIS-29) physical dimension, and 36-item Short-Form Health Survey (SF-36) physical component summary (PCS), with Spearman's correlation coefficients (ρ) of 0.922, 0.756, 0.933, and -0.874, respectively. In patients with NMOSD, the baseline MSWS-12 total score showed strong correlations with scores for the EDSS, MSIS-29 physical dimension, and SF-36 PCS (ρ=0.769, 0.910, and -0.852, respectively), and moderate correlations with scores for the T25FW and Fatigue Severity Scale-9 (ρ=0.597 and 0.630, respectively). CONCLUSIONS: The Korean version of the MSWS-12 appears to be a valid and reliable scale that can be used for Korean patients with MS. The MSWS-12 can also be applied to patients with NMOSD.