Chinese Amyotrophic Lateral Sclerosis Patients Research Articles

PCDHA9 as a candidate gene for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease. To identify additional genetic factors, we analyzed exome sequences in a large cohort of Chinese ALS patients and found a homozygous variant (p.L700P) in PCDHA9 in three unrelated patients. We generated Pcdhα9 mutant mice harboring either orthologous point mutation or deletion mutation. These mice develop progressive spinal motor loss, muscle atrophy, and structural/functional abnormalities of the neuromuscular junction, leading to paralysis and early lethality. TDP-43 pathology is detected in the spinal motor neurons of aged mutant mice. Mechanistically, we demonstrate that Pcdha9 mutation causes aberrant activation of FAK and PYK2 in aging spinal cord, and dramatically reduced NKA-α1 expression in motor neurons. Our single nucleus multi-omics analysis reveals disturbed signaling involved in cell adhesion, ion transport, synapse organization, and neuronal survival in aged mutant mice. Together, our results present PCDHA9 as a potential ALS gene and provide insights into its pathogenesis.

Rare DNAJC7 Variants May Play a Minor Role in Chinese Patients with ALS.

DnaJ heat shock protein family member C7 gene (DNAJC7) has been identified as a genetic risk factor for amyotrophic lateral sclerosis (ALS). In our study, we aimed to screen for rare variants in DNAJC7 in a large cohort of Chinese ALS patients, and investigate the genotype-phenotype correlation of DNAJC7 in ALS. Four (0.19%) variants of DNAJC7 with minor allele frequency (MAF) < 0.1% among 2124 patients were identified, including 1 protein-truncating variant and 3 missense variants, all of which were predicted to be damaging. The patients carrying variants of DNAJC7 in our cohort tented to have a limb onset and a relatively slow disease progression. However, burden analysis did not show an enrichment of rare damaging variants in ALS patients compared to controls. Further analysis involving diverse regions and larger sample size is necessary to elucidate the role of DNAJC7 in the pathogenicity of ALS.

Development of a robust UPLC-MS/MS method for the quantification of riluzole in human plasma and its application in pharmacokinetics.

Introduction: The aim of the present study was to establish a simple method for the determination of riluzole in human plasma by ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and apply it for the determination of riluzole in amyotrophic lateral sclerosis (ALS) patients. Methods: Samples were prepared by protein precipitation and were then gradient-eluted on a column of ACQUITY UPLC® HSS T3 by using 0.1% formic acid acetonitrile and 0.1% formic acid water as the mobile phase. Detection was performed on a Xevo TQ-S tandem mass spectrometer in the multiple-reaction monitoring mode using positive electrospray ionization. Validation was performed in the range of 5-800ng/mL. Results and discussion: Three batches of precision accuracy, selectivity, matrix effects, extraction recovery, and stability were also verified and met the requirements. The results showed that the method was reliable and successfully applied to the pharmacokinetics study of riluzole in Chinese amyotrophic lateral sclerosis patients. Meanwhile, in comparison with other prior published methods, our method has the advantages of simple sample preparation, relatively short running time, and small plasma sample consumption, which represented a high-throughput sample determination potential.

TBK1 variants in Chinese patients with amyotrophic lateral sclerosis: Genetic analysis and clinical features.

Haploinsufficiency of TANK-binding kinase 1 (TBK1) loss-of-function (LoF) variants has been shown to be pathogenic in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, the genetic spectrum of TBK1 and clinical features of ALS patients with TBK1 variants remain largely unknown in Asians. Genetic analysis was performed on 2011 Chinese ALS patients. Software was used to predict the deleteriousness of missense variants in TBK1. In addition, PubMed, Embase and Web of Science were searched for related literature. Twenty-six TBK1 variants were identified in 33 of 2011 ALS patients, including six novel LoF variants (0.3%) and 20 rare missense variants, 12 of which were predicted to be deleterious (0.6%). In addition to TBK1 variants, 11 patients had other ALS-related gene variants. Forty-two previous studies found that the frequency of TBK1 variants was 1.81% in ALS/FTD patients. The frequency of TBK1 LoF variants in ALS was 0.5% (Asians 0.4%; Caucasian 0.6%) and that of missense variants was 0.8% (Asians 1.0%; Caucasian 0.8%). ALS patients with TBK1 LoF variants affecting the kinase domain had a significantly younger age of onset than patients carrying LoF variants affecting the coiled coil domains CCD1 and CCD2. FTD has a frequency of 10% in Caucasian ALS patients with TBK1 LoF variants, which was not found in our cohort. Our study expanded the genotypic spectrum of ALS patients with TBK1 variants and found that the clinical manifestations of TBK1 carriers are diverse.

A Predictive Model and Survival Analysis for Tube Feeding in ALS Patients: A Prospective Cohort Study in a Chinese ALS Clinic

Objectives. Tube feeding is an effective way to provide nutritional support for amyotrophic lateral sclerosis (ALS) patients with severe dysphagia. Currently, the predictors of tube feeding and the survival affected by tube feeding were poorly studied in Chinese ALS patients. Therefore, we aimed to explore predictive factors and establish a prediction model to quantitatively predict the risk of tube feeding. Furthermore, we explored the survival benefit provided by tube feeding. Methods. In this longitudinal, prospective cohort study, we included patients diagnosed with ALS using the Awaji criteria at the ALS clinic in Huashan Hospital. Follow-up was conducted by telephone interview from January 1, 2019, to December 30, 2021, or until death. All statistical analyses were performed using R software. Results. Overall, 218 patients were recruited for the study. The multivariate Cox regression analysis showed a high ALSFRS-R slope (adjusted hazard ratio aHR = 4.94 (95% confidence interval (95% CI: 2.26-10.81), p &lt; 0.001 ), low bulbar score ( aHR = 0.81 (95% CI: 0.69-0.96), p = 0.01 ), history of ischemic stroke ( aHR = 5.69 (95% CI: 1.3-24.82), p = 0.02 ), and bulbar involvement ( aHR = 11.87 (95% CI: 1.42-99.31), p = 0.02 ) as independent risk factors of tube feeding. The nomogram model was established with moderate discrimination and calibration. Among 71 ALS patients with tube feeding indication, 33.8% accepted gastrostomy suggestion and 14.1% had nasogastric tube (NGT) insertion. However, gastrostomy and NGT did not accelerate disease progression ( aHR = 0.57 (95% CI: 0.20-1.67), p = 0.31 and aHR = 1.72 (95% CI: 0.43-6.88), p = 0.43 , respectively). Conclusions. We developed a nomogram that could be a prediction tool to predict individual timing of tube feeding for ALS patients. In addition, we found that gastrostomy and NGT did not affect ALS patients’ survival.

Genetic and Phenotypic Spectrum of Amyotrophic Lateral Sclerosis Patients with CCNF Variants from a Large Chinese Cohort

Cyclin F (CCNF) variants have been found to be associated with amyotrophic lateral sclerosis (ALS)/frontotemporal dementia (FTD). However, the genetic and clinical characteristics of ALS patients who carry CCNF variants are largely unknown. Genetic analysis was performed for 1587 Chinese ALS patients, and missense variants were predicted by software analyses. Additionally, we searched PubMed, Embase, and Web of Science for relevant literature and conducted a meta-analysis of the frequency of variants. In our ALS cohort, we identified 29 nonsynonymous variants in 41 ALS patients. Among these ALS patients, 18 (1.1%) were carriers of 15 rare missense variants that were considered probably pathogenic variants, and 11 of 15 variants were novel. Seven relevant studies were identified, and a total of 43 CCNF variants in 59 ALS patients with a frequency of 0.8% were reported. The ratio of males to females in our cohort (10/8) was similar to that in Caucasian populations (4/7) and significantly higher than that in Asian populations (10/1). The proportion of bulbar onset in Caucasian CCNF carriers was similar to our cohort (25.0 vs. 27.8%); however, bulbar onset had never been reported in previous Asian studies (0/11). FTD was not found in CCNF carriers in previous Asian studies and our cohort, but it has been reported in a FALS cohort (1/75) of Caucasian individuals. There were some differences in the clinical characteristics among different ethnic ALS populations. More basic scientific studies are needed to elucidate the pathogenic mechanisms and genotype-phenotype associations of CCNF variants.

Prevalence and associated factors of apathy in Chinese ALS patients.

This study aimed to explore the prevalence and clinical correlates of apathy in amyotrophic lateral sclerosis (ALS) in a cohort of Chinese patients. A total of 1,013 ALS patients were enrolled in this study. Apathy was recorded during face-to-face interviews using Frontal Behavioral Inventory, and other patient characteristics, including depression, anxiety, and cognitive function, were collected using Hamilton Depression Rating Scale (HDRS), Hamilton Anxiety Rating Scale (HARS), and Chinese version of Addenbrooke's Cognitive Examination-revised. Health-related quality of life of ALS patients and their caregivers was also evaluated, and the potential factors associated with apathy were explored using forward binary regression analysis. Survival was analyzed using the Cox proportional hazards model. The prevalence of apathy in all patients was 28.9%. Patients in the late disease stage had a higher prevalence of apathy than those in the early disease stage. Furthermore, patients with apathy had a lower ALS Functional Rating Scale revised (ALSFRS-R) score, higher HDRS score, HARS score and higher proportion of reported problems in the anxiety/depression. Additionally, their caregivers had higher score of depression and higher Zarit-Burden Interview scores. Multivariate regression analysis revealed that apathy in ALS was associated with the onset region (p = 0.027), ALSFRS-R score (p = 0.007), depression (p = 0.001) and anxiety (p < 0.001). Apathy had a significant negative effect on survival in ALS patients (p = 0.032). Apathy is relatively common (28.9%) in Chinese patients with ALS. Apathy is related to both the severity of the disease, and the presentation of non-motor symptoms in ALS, such as depression and anxiety disorders. Apathy is an independent prognostic factor for survival and requires early intervention and management.

Intermediate-Length GGC Repeat Expansion in NOTCH2NLC Was Identified in Chinese Patients with Amyotrophic Lateral Sclerosis.

GGC repeat expansions in the 5' untranslated region (5'UTR) of the Notch Homolog 2 N-terminal-like C gene (NOTCH2NLC) have been reported to be the genetic cause of neuronal intranuclear inclusion disease (NIID). However, whether they exist in other neurodegenerative disorders remains unclear. To determine whether there is a medium-length amplification of NOTCH2NLC in patients with amyotrophic lateral sclerosis (ALS), we screened 476 ALS patients and 210 healthy controls for the presence of a GGC repeat expansion in NOTCH2NLC by using repeat-primed polymerase chain reaction (RP-PCR) and fragment analysis. The repeat number in ALS patients was 16.11 ± 5.7 (range 7-46), whereas the repeat number in control subjects was 16.19 ± 3.79 (range 10-29). An intermediate-length GGC repeat expansion was observed in two ALS patients (numbers of repeats: 45, 46; normal repeat number ≤ 40) but not in the control group. The results suggested that the intermediate NOTCH2NLC GGC repeat expansion was associated with Chinese ALS patients, and further functional studies for intermediate-length variation are required to identify the mechanism.

Investigation of a Fused in Sarcoma Splicing Mutation in a Chinese Amyotrophic Lateral Sclerosis Patient.

Genetic mutations of fused in sarcoma (FUS) causing amyotrophic lateral sclerosis (ALS) may disrupt mRNA splicing events. For example, the FUS c.1394-2delA variant was reported in two western ALS patients, but its molecular mechanism is unclear. In this study, we aim to investigate FUS splice site mutations in Chinese ALS patients. Sanger sequencing was used to identify FUS splicing mutations in Chinese ALS patients. We combined a deep learning tool (SpliceAI), RNA sequencing, and RT-PCR/RT-qPCR to analyze the effect of FUS c.1394-2delA mutation on RNA splicing and expression. AlphaFold was used to predict the protein structure of mutant FUS. In transfected cell lines, we used immunofluorescence to assess cytoplasmic mislocalization of mutant FUS protein. We identified a de novo FUS splice acceptor site mutation (c.1394-2delA, p. Gly466Valfs*14) in one Chinese sporadic ALS patient, which is linked to exon 14 skipping, and upregulated total FUS mRNA expression. The FUS splice site mutation was predicted to be translated into a truncated protein product at C-terminal. In vitro studies revealed that the FUS mutation increased cytoplasmic mislocalization in both HEK293T and SH-SY5Y cells. We identified a de novo FUS splicing mutation (c.1394-2delA, p. Gly466Valfs*14) in 1 out of 233 Chinese ALS patients. It caused abnormal RNA splicing, upregulated gene expression, truncated FUS translation, and cytosolic mislocalization. Our findings suggested that FUS splice site mutation is rare in Chinese ALS patients and extended our knowledge of molecular mechanisms of the FUS c.1394-2delA mutation.

No Association between the SORD Gene and Amyotrophic Lateral Sclerosis in a Chinese Cohort.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder. Recently a juvenile ALS patient was reported carrying the c.757delG mutation of the sorbitol dehydrogenase (SORD) gene, which was also a related mutation of Charcot-Marie-Tooth disease (CMT) and distal hereditary motor neuropathy (dHMN). ALS shares pathogenesis and overlapping genes with CMT and dHMN. We used whole-exome sequencing technology to screen the full-length SORD gene in 601 Chinese sporadic ALS patients and 174 controls without a history of neurological diseases. No SORD pathogenic variants were identified in the ALS patients. Our current results did not find an association between SORD and ALS in Chinese patients, and further studies will be required.

Mutation spectrum of chinese amyotrophic lateral sclerosis patients with frontotemporal dementia

BackgroundStudies have reported that a noncoding hexanucleotide repeat in C9ORF72, is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) among Caucasian population, nevertheless it is rare in Chinese population. Therefore, we aimed to investigate the mutation spectrum of Chinese ALS patients with FTD (ALS-FTD).MethodsALS patients with and without cognitive impairments were enrolled. Clinical features were collected including age, sex, disease duration, ALSFRS-r, family history and cognitive evaluation. Thirty-six ALS genes were screened by whole exome sequencing (WES) and repeat-primed polymerase chain reaction (PCR) were used for detection of and abnormal repeat expansions of C9ORF72.ResultsA total of 1208 patients, including 66 familial ALS (FALS) and 1142 sporadic ALS (SALS) patients were included. Twenty-three patients with sporadic ALS and one familial ALS index had concomitant FTD, which accounts for 1.99% (24/1208) of patients with ALS. In sporadic ALS-FTD, one case harboring C9ORF72 expansion variant, two cases harboring ANXA11 variants and one individual carrying CCNF variant were identified. A recurrent UBQLN2 variant was detected in a familial ALS-FTD patient. All of the ALS-FTD patients carrying variants in known causative genes manifested motor symptom onset (two bulbar onset and three limb onset) and developed cognitive impairment thereafter. It is not easy to draw a conclusion of the genotype-phenotype association in ALS-FTD with certain variants, limited by the small number of patients.ConclusionOur findings provide an overview of spectrum of genetic variants in Chinese ALS-FTD patients. Variants of uncertain significance in UBQLN2, ANXA11 and CCNF were identified and further studies are required for causal relations of these variants with ALS-FTD.

Genetic and clinical characteristics of ALS patients with NEK1 gene variants

NIMA-related kinase 1(NEK1) gene was related to amyotrophic lateral sclerosis (ALS). However, genetic spectrum and clinical characteristics of ALS patients with NEK1 variants was largely unknown. We conducted genetic analysis on 1587 Chinese ALS patients and used software to predict the pathogenicity of NEK1 missense variant. We searched the literatures in PubMed, Embase, and Web of Science. In our ALS cohort, 42 ALS patients (2.6%) carried NEK1 variants, including 10 novel loss-of-function (LoF) variant carriers and 32 missense variant carriers. 90% of the NEK1 LoF variant carriers had upper limbs onset. The median survival time of LoF variant carriers tend to be shorter than that of probably pathogenic variant carriers (23.80 vs. 42.77 months). In 16 related studies, 167 different NEK1 variants, including 62 LoF and 105 missense variants, were found in 237 reported ALS patients. It was found that the survival time of LoF variant carriers was significantly shorter than that of missense variant carriers. Our study expanded the genotype and phenotype spectrum of ALS patients with NEK1 variants.

Pain-Related Factors and Their Impact on Quality of Life in Chinese Patients With Amyotrophic Lateral Sclerosis.

ObjectivesPain is considered a common symptom in amyotrophic lateral sclerosis (ALS). However, the results of studies on pain in ALS are limited and inconsistent. The aim of our study was to comprehensively evaluate the potential factors of pain and effects on quality of life (QoL) in patients with ALS from China.Participants and MethodsPatients were eligible if they fulfilled the criteria of probable and definitive ALS according to the revised El Escorial criteria. Pain was assessed by the Brief Pain Inventory (BPI). Disease severity, sleep quality, fatigue, anxiety, depression, and quality of life (QoL) were evaluated in ALS patients by the ALS Functional Rating Scale-revised (ALSFRS-R) and ALS severity scale (ALSSS), Pittsburgh Sleep Quality Index (PSQI), Fatigue Severity Scale (FSS), Hamilton Anxiety Rating Scale (HARS), Hamilton Depression Rating Scale (HDRS) and McGill Quality of Life Questionnaire (MQOL). Then, the clinical characteristics of ALS patients with pain were compared with those without pain. Last, associated factors of pain, as well as impact on QoL in Chinese ALS patients, were assessed.ResultsA total of 86 ALS patients were included. ALS patients with pain tended to have higher FSS scores and poorer QoL. The FSS score and ALSSS [lower extremity (LE) + upper extremity (UE)] were associated with pain in ALS patients. The ALS Functional Rating Scale-revised (ALSFRS-R), Pain Severity Index (PSI), HARS and HDRS scores were significantly associated with both the physical and psychological domains of QoL.ConclusionOur study was the first to comprehensively evaluate factors associated with pain in Chinese ALS patients, finding that fatigue can be a risk factor for pain and ALSSS (LE + UE) score was related with pain intensity. Additionally, we identified the adverse effects of ALSSS (LE + UE), HARS and HDRS scores on QoL in Chinese ALS patients.

Genotype-phenotype association of TARDBP mutations in Chinese patients with amyotrophic lateral sclerosis: a single-center study and systematic review of published literature.

This study aims to determine the genetic and clinical features of TARDBP-mutated patients in our cohort of Chinese patients with amyotrophic lateral sclerosis (ALS) combined with data in the literature. We performed TARDBP mutation screening in 1258 Chinese ALS patients, including 1204 sporadic ALS (sALS) and 54 familial ALS (fALS) patients. A systematic literature review was conducted by searching TARDBP-mutated patients from China in the online databases. In our cohort, the mutant frequency of TARDBP variants was 0.3% (4/1258), with two recurrent variants (p.G294V, p.G298V) and one novel variant (p.S332G) identified. Combining with data in the literature review, the TARDBP-mutant frequency in the Chinese population was 1.4% (83/5998), with 0.8% (46/5470) in sALS and 7.0% (37/528) in fALS. Most patients had limb onset (63.0%), with an average life expectancy of 4.3years (range 0.5-13). Disease durations significantly differed (p = 0.002), with p.M337V showing the longest duration (80months) and p.N378D showing the shortest duration (16.7months). Our study found that TARDBP mutation was not rare in Chinese fALS patients. Different TARDBP mutations were associated with specific features in phenotypes.

Phenotype of VCP Mutations in Chinese Amyotrophic Lateral Sclerosis Patients.

Mutations in the valosin-containing protein (VCP) gene have been linked to amyotrophic lateral sclerosis (ALS) in the Caucasian populations. However, the phenotype of VCP mutations in Chinese patients with (ALS) remains unclear. Targeted next-generation sequencing covered 28 ALS-related genes including the VCP gene was undertaken to screen in a Chinese cohort of 275 sporadic ALS cases and 15 familial ALS pedigrees. An extensive literature review was performed to identify all patients with ALS carrying VCP mutations previously reported. The clinical characteristics and genetic features of ALS patients with VCP mutations were reviewed. One known p.R155C mutation in the VCP gene was detected in two siblings from a familial ALS pedigree and two sporadic individuals. In addition, the same VCP p.R155C mutation was detected in an additional patient with ALS referred in 2021. Three patients with VCP p.R155C mutation presented with muscular weakness starting from proximal extremities to distal extremities. The other patient developed a phenotype of Paget's disease of bone in addition to the progressive muscular atrophy. We reported the first VCP mutation carrier manifesting ALS with Paget's disease of bone in the Chinese population. Our findings expand the phenotypic spectrum of the VCP mutations in Chinese patients with ALS and suggest that ALS patients with VCP p.R155C mutations tend to present with relatively young onset, symmetrical involvement of proximal muscles weakness of arms or legs, and then progressed to distal muscles of limbs.

Plasma Uric Acid Helps Predict Cognitive Impairment in Patients With Amyotrophic Lateral Sclerosis.

Objective: Uric acid as an antioxidant plays an important role in neurodegenerative disease. Our objective is to investigate the relationship between plasma uric acid and cognitive impairment in patients with amyotrophic lateral sclerosis (ALS).Methods: In this cross-sectional study, 124 ALS patients were screened by the Edinburgh Cognitive and Behavioral Screen (ECAS) and classified according to the revised Strong's criteria. Additionally, based on total ECAS cut-off score patients were categorized into those with cognitive impairment (ALS-cie) and those without cognitive impairment (ALS-ncie), and clinical data and uric acid level were compared between the two groups. Parameters with significant differences were further included in a multivariate linear regression analysis with ECAS score as a dependent variable. Hold-out validation was performed to evaluate the fitness of regression model.Results: Up to 60% of ALS patients showed cognitive or/and behavioral impairment. The ALS-cie group had lower education level (p < 0.001), older age at symptom onset (p = 0.001), older age at testing (p = 0.001), and lower plasma uric acid (p = 0.01). Multivariate analysis showed increased uric acid (β = 0.214, p = 0.01), lower age at testing (β = −0.378, p < 0.001), and higher education level (β = 0.424, p < 0.001) could predict higher ECAS score (F = 19.104, R2 = 0.381, p < 0.0001). Validation analysis showed that predicted ECAS score was significantly correlated with raw ECAS score in both the training set (rs = 0.621, p < 0.001) and the testing set (rs = 0.666, p < 0.001).Conclusions: Cognitive impairment was a common feature in our Chinese ALS patients. Plasma uric acid might help evaluate the risk of cognitive impairment in ALS patients when combined with education level and age at testing.

Rare CYLD Variants in Chinese Patients With Amyotrophic Lateral Sclerosis.

Background: CYLD Lysine 63 Deubiquitinase gene (CYLD) was recently identified to be a novel causative gene for frontal temporal dementia (FTD)-amyotrophic lateral sclerosis (ALS). In the current study, we aimed to (1) systematically screen the mutations of CYLD in a large cohort of Chinese ALS patients, (2) study the genotype–phenotype correlation, and (3) explore the role of CYLD in ALS via rare variants burden analysis. Methods: A total of 978 Chinese sporadic ALS (sALS) patients and 46 familial ALS (fALS) patients were sequenced with whole-exome sequencing and analyzed rare variants in CYLD with minor allele frequency <0.1%. Results: In total, seven rare missense variants in CYLD have been identified in 7 (0.72%) patients among 978 sALS patients. Two (4.3%) rare missense variants were identified among the 46 fALS cases, in which one patient was diagnosed as having comorbidity of ALS and progressive supranuclear palsy (PSP). Moreover, the burden analysis indicated no enrichment of rare variants in CYLD among patients with ALS. Conclusion: In conclusion, our study extended the genotype and phenotype of CYLD in ALS, but the pathogenicity of these variants needs to be further verified. Moreover, burden analysis argued against the role of CYLD in the pathogenesis of ALS. More studies from different ethnicities would be needed.

Characteristics of Late-Onset Amyotrophic Lateral Sclerosis in a Chinese Cohort

Objective: This retrospective study analyzed the clinical characteristics and prognosis of the elderly amyotrophic lateral sclerosis (ALS) population in a large sample. Methods: The study included 1,005 patients with sporadic ALS admitted to Chinese PLA General Hospital between March 2011 and March 2021. We stratified the ALS patients into young and old groups using 2 cutoffs for the age at disease onset (≥65 or ≥70 years old) and compared their demographic, clinical, and survival data. Results: The mean onset age of all patients was 52.79 ± 10.55 years, with 123 (12.24%) having a disease onset ≥65 years and 44 (4.38%) having an onset ≥70 years. There were 624 (62.1%) male patients. More bulbar-onset cases were in the late-onset group (p = 0.001). The sex distribution, time from onset to diagnosis, and the time of symptom spread from spinal or bulbar localization to a generalized localization did not differ between groups. Late-onset patients progressed more rapidly and had a significantly shorter survival. Conclusions: Chinese ALS patients have an earlier age at onset and a relatively smaller proportion of old onset than European and Japanese patients. Elderly patients are more likely to have bulbar onset, which is related to rapid progression and a shorter survival.

GLT8D1 may not be significant in Chinese sporadic amyotrophic lateral sclerosis patients

To detect the mutation frequency of exon 4 of amyotrophic lateral sclerosis (ALS) in a new disease-causing gene, GLT8D1 (NM_018446), in Chinese patients, we used whole-exome sequencing technology to screen the full-length GLT8D1 gene in 539 Chinese sporadic ALS patients and 176 controls without a history of neurological diseases. Then, we sequenced the coding region of exon 4 in the GLT8D1 gene in a cohort consisting of 256 sporadic ALS patients. Our current results did not find an association between GLT8D1 and ALS in Chinese patients, and further studies will be required.

Rare variants of HSPB1 are probably associated with amyotrophic lateral sclerosis

To explore the association between rare HSPB1 variants and amyotrophic lateral sclerosis (ALS). We performed next-generation sequencing for 166 Chinese ALS patients to screen for possible pathogenic rare variants of HSPB1. The control individuals were obtained from 1000 Genome Project and an in-house whole-exome sequencing database. The Sequence Kernel Association Test (SKAT) and the SKAT-optimal test (SKAT-O) were used to identify the association between rare HSPB1 variants and ALS. We identified 3 possible pathogenic rare variants of HSPB1 (all were missenses), including c.379C>T (p.R127W), c.446A>C (p.D149A) and c.451A>C (p.T151P). Compared with 1000 Genome Project, SKAT p=3.61×10-7 and SKAT-O p=1.62×10-6; while compared with the in-house database, SKAT p=9.99×10-4, SKAT-O p= 1.80×10-3. We analyzed the phenotypes of rare HSPB1 variant carriers and found no specific clinical characteristics associated with these variants. Rare variants of HSPB1 are probably associated with the pathogenesis of ALS.