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ImportanceCIS to MS conversion rates vary depending on population cohorts, initial manifestations, and durations of follow-up.ObjectiveTo investigate conversion rate of patients from CIS to MS and the prognostic significance of demographic and clinical variables in Taiwanese population.DesignNationwide, prospective, multi-centric, observational study from November 2008 to November 2014 with 4 years follow-up.SettingMulti-centre setting at 5 institutions in Taiwan.Participants152 patients having single clinical event potentially suggestive of MS in last 2 years were enrolled as consecutive sample. 33 patients were lost to follow-up and 16 patients did not complete the study.103 patients completed the study.Intervention(s) (for clinical trials) or exposure(s) (for observational studies)Natural progression from first episode of CIS to MS or NMO was observed.Main outcome(s) and measure(s)Variables analysed were 'proportion of patients converting to MS or NMO after first episode of CIS', 'duration between first episode of neurological event and diagnosis of MS', 'status of anti-AQP4 IgG' and 'length of longest contiguous spinal cord lesion in MS patients'. Association between baseline characteristics and progression to MS from CIS was analyzed using multiple logistic regression. Multivariate time dependent effect of baseline characteristics on progression to MS was plotted.Results14.5% patients with CIS converted to MS after 1.1 ± 1.0 years with greater predisposition (18.8%) in those having syndromes referable to the cerebral hemispheres. Conversion rate from ON to MS was 9.7%. 90.9% patients had mild disease course. 46.7% patients had abnormal MRIs at baseline, with 0.6±0.5 contrast enhanced lesions. 'Below normal BMI' and 'MRI lesion load (≥ 4 lesions)' were identified as risk indicators for the development of MS. Amongst the patients who developed NMO as diagnosed by modern criteria, 80% were positive for anti-AQP4 IgG antibody.Conclusions and relevance'Below normal BMI' and 'number of demyelinating lesions (≥4)' are significant predictors of conversion from CIS to MS. A low conversion rate to MS in Taiwanese CIS patients and majority of them having a mild course and minimal disability suggest the roles of geographic, genetic and ethnic factors.Trial registrationNon-trial observational study.

BACKGROUND:A small group of patients with inherited neuropathy that has been shown to be caused by mutations in the BSCL2 gene. However, little information is available about the role of BSCL2 mutations in inherited neuropathies in Taiwan. METHODOLOGY AND PRINCIPAL FINDINGS:Utilizing targeted sequencing, 76 patients with molecularly unassigned Charcot-Marie-Tooth disease type 2 (CMT2) and 8 with distal hereditary motor neuropathy (dHMN), who were selected from 348 unrelated patients with inherited neuropathies, were screened for mutations in the coding regions of BSCL2. Two heterozygous BSCL2 mutations, p.S90L and p.R96H, were identified, of which the p.R96H mutation is novel. The p.S90L was identified in a pedigree with CMT2 while the p.R96H was identified in a patient with apparently sporadic dHMN. In vitro studies demonstrated that the p.R96H mutation results in a remarkably low seipin expression and reduced cell viability. CONCLUSION:BSCL2 mutations account for a small number of patients with inherited neuropathies in Taiwan. The p.R96H mutation is associated with dHMN. This study expands the molecular spectrum of BSCL2 mutations and also emphasizes the pathogenic role of BSCL2 mutations in molecularly unassigned hereditary neuropathies.

BackgroundMutations in the PRRT2 gene have recently been identified in patients with familial paroxysmal kinesigenic dyskinesia with infantile convulsions (PKD/IC) and patients with sporadic PKD/IC from several ethnic groups. To extend these recent genetic reports, we investigated the frequency and identities of PRRT2 mutations in a cohort of Taiwanese patients with PKD/IC.Methodology and principal findingsWe screened all 3 coding exons of PRRT2 for mutations in 28 Taiwanese patients with PKD/IC. Among them, 13 had familial PKD/IC and 15 were apparently sporadic cases. In total, 7 disparate mutations were identified in 13 patients, including 8 familial cases and 5 apparently sporadic cases. The mutations were not present in 500 healthy controls. Four mutations were novel. One patient had a missense mutation and all other patients carried PRRT2 mutations putatively resulting in a protein truncation. Haplotype analysis revealed that 5 of the 7 patients with the PRRT2 p.R217Pfs*8 mutation shared the same haplotype linked to the mutation.Conclusions and significancePRRT2 mutations account for 61.5% (8 out of 13) of familial PKD/IC and 33.3% (5 out of 15) of apparently sporadic PKD/IC in the Taiwanese cohort. Most patients with the PRRT2 p.R217Pfs*8 mutation in Taiwan likely descend from a single common ancestor. This study expands the spectrum of PKD/IC-associated PRRT2 mutations, highlights the pathogenic role of PRRT2 mutations in PKD/IC, and suggests genetic heterogeneity within idiopathic PKD.

BACKGROUND: Charcot-Marie-Tooth disease type 2 (CMT2) is a clinically and genetically heterogeneous group of inherited axonal neuropathies. The aim of this study was to extensively investigate the mutational spectrum of CMT2 in a cohort of patients of Han Chinese. METHODOLOGY AND PRINCIPAL FINDINGS: Genomic DNA from 36 unrelated Taiwanese CMT2 patients of Han Chinese descent was screened for mutations in the coding regions of the MFN2, RAB7, TRPV4, GARS, NEFL, HSPB1, MPZ, GDAP1, HSPB8, DNM2, AARS and YARS genes. Ten disparate mutations were identified in 14 patients (38.9% of the cohort), including p.N71Y in AARS (2.8%), p.T164A in HSPB1 (2.8%), and p.[H256R]+[R282H] in GDAP1 (2.8%) in one patient each, three NEFL mutations in six patients (16.7%) and four MFN2 mutations in five patients (13.9%). The following six mutations were novel: the individual AARS, HSPB1 and GDAP1 mutations and c.475-1G>T, p.L233V and p.E744M mutations in MFN2. An in vitro splicing assay revealed that the MFN2 c.475-1G>T mutation causes a 4 amino acid deletion (p.T159_Q162del). Despite an extensive survey, the genetic causes of CMT2 remained elusive in the remaining 22 CMT2 patients (61.1%). CONCLUSIONS AND SIGNIFICANCE: This study illustrates the spectrum of CMT2 mutations in a Taiwanese CMT2 cohort and expands the number of CMT2-associated mutations. The relevance of the AARS and HSPB1 mutations in the pathogenesis of CMT2 is further highlighted. Moreover, the frequency of the NEFL mutations in this study cohort was unexpectedly high. Genetic testing for NEFL and MFN2 mutations should, therefore, be the first step in the molecular diagnosis of CMT2 in ethnic Chinese.