Amyotrophic lateral sclerosis patients with various gene mutations show diverse motor phenotypes and survival in China.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterised by progressive degeneration of motor neurons. Genetic factors have a substantial impact on ALS. Therefore, this study aimed to explore the correlation between genotype (SOD1, TARDBP, FUS, C9orf72) and phenotype in ALS. METHODS: Genetic analysis was performed on 2038 patients with ALS, among which 1696 patients with sporadic ALS (SALS) as controls for genotype-phenotype analysis, and 1602 SALS as controls for survival analysis. Logistic regression and Cox proportional hazards models were used for statistical analysis. RESULTS: A total of 172 patients with ALS with the gene mutations were included in the statistical analysis (SOD1, n=65; FUS, n=43; TARDBP, n=27; C9orf72, n=37). SOD1 mutations were more frequent in flail leg phenotype (OR 7.317, p=0.001) and less in bulbar phenotype (OR 0.222, p=0.038). C9orf72 expansions exhibited higher frequency in bulbar phenotype (OR 2.770, p=0.008). SOD1 and FUS mutations were significantly associated with earlier age of onset (HR 2.039, p<0.001; HR 1.762, p=0.001). The patients with SOD1 mutations, C9orf72 expansions and those carrying pathogenic FUS mutations had significantly increased death risk (HR 2.217, p<0.001; HR 1.694, p=0.008; HR 1.652, p=0.036). The increased risk of death in ALS with C9orf72 expansions was significant in females (HR 2.419, p=0.014) but not in males (HR 1.442, p=0.128). CONCLUSION: Our study revealed distinct motor phenotypic tendencies in patients with ALS with different genotypes, indicating variations in the vulnerability of motor neurons during the disease's progression. Furthermore, we made novel discoveries regarding survival of different gene mutations, warranting further investigation.

Genetic Modifiers of Age at Onset for Amyotrophic Lateral Sclerosis: A Genome-Wide Association Study.

OBJECTIVE: Age at onset (AAO) is an essential clinical feature associated with disease progression and mortality in amyotrophic lateral sclerosis (ALS). Identification of genetic variants and environmental risk factors influencing AAO of ALS could help better understand the disease's biological mechanism and provide clinical guidance. However, most genetic studies focused on the risk of ALS, while the genetic background of AAO is less explored. This study aimed to identify genetic and environmental determinants for AAO of ALS. METHODS: We performed a genome-wide association analysis using a Cox proportional hazards model on AAO of ALS in 10,068 patients. We further conducted colocalization analysis and in-vitro functional exploration for the target variants, as well as Mendelian randomization analysis to identify risk factors influencing AAO of ALS. RESULTS: The total heritability of AAO of ALS was ~0.16 (standard error [SE] = 0.03). One novel locus rs2046243 (CTIF) was significantly associated with earlier AAO by ~1.29 years (p = 1.68E-08, beta = 0.10, SE = 0.02). Functional exploration suggested this variant was associated with increased expression of CTIF in multiple tissues including the brain. Colocalization analysis detected a colocalization signal at the locus between AAO of ALS and expression of CTIF. Causal inference indicated higher education level was associated with later AAO. INTERPRETATION: These findings improve the current knowledge of the genetic and environmental etiology of AAO of ALS, and provide a novel target CTIF for further research on ALS pathogenesis and potential therapeutic options to delay the disease onset. ANN NEUROL 2023;94:933-941.

Mutation screening of SPTLC1 and SPTLC2 in amyotrophic lateral sclerosis.

BACKGROUND: Recently, several rare variants of SPTLC1 were identified as disease cause for juvenile amyotrophic lateral sclerosis (ALS) by disrupting the normal homeostatic regulation of serine palmitoyltransferase (SPT). However, further exploration of the rare variants in large cohorts was still necessary. Meanwhile, SPTLC2 plays a similar role as SPTLC1 in the SPT function. METHODS: To explore the genetic role of SPTLC1 and SPTLC2 in ALS, we analyzed the rare protein-coding variants in 2011 patients with ALS and 3298 controls from the Chinese population with whole exome sequencing. Fisher's exact test was performed between each variant and disease risk, while at gene level over-representation of rare variants in patients was examined with optimized sequence kernel association test (SKAT-O). RESULTS: Totally 33 rare variants with minor allele frequency < 0.01 were identified, including 17 in SPTLC1 and 16 in SPTLC2. One adult-onset patient carried the variant p.E406K (SPTLC1) which was reported in previous study. Additionally, three adult-onset patients carried variants in the same amino acids as the variants identified in previous studies (p.Y509C, p.S331T, and p.R239Q in SPTLC1). At gene level, rare variants of SPTLC1 and STPLC2 were not enriched in patients. CONCLUSION: These results broadened the variant spectrum of SPTLC1 and SPTLC2 in ALS, and paved the way for future research. Further replication was still needed to explore the genetic role of SPTLC1 in ALS.

The impact of maternal smoking during pregnancy and the age of smoking initiation on incident dementia: A prospective cohort study.

INTRODUCTION: The impact of early-life tobacco exposure on dementia has remained unknown. METHODS: Using the UK Biobank, the associations of maternal smoking during pregnancy (MSDP) and age of smoking initiation (ASI) with the onset time of all-cause dementia were estimated with accelerated failure time models. The effects of MSDP and ASI on brain structure and their genetic correlation to Alzheimer's disease (AD) were analyzed. A Mendelian randomization (MR) analysis was conducted. RESULTS: The time ratios for smokers starting in childhood, adolescence, and adulthood (vs never smokers) were 0.87 (0.76 to 0.99), 0.92 (0.88 to 0.96), and 0.95 (0.89 to 1.01). MSDP and smoking in adolescence altered many brain regions, including the hippocampus. In genetic analysis, MSDP was genetically and causally linked to AD, and a younger ASI was genetically correlated to a higher AD risk. DISCUSSION: Early-life smoking accelerated dementia onset and was genetically correlated to AD. MSDP demonstrated genetic and causal linkage to AD risks. HIGHLIGHTS: Unlike the commonly used Cox proportional hazards model, this article uses a parametric survival analysis method - the accelerated failure model - to explore the relationship between exposure to onset time. It can be used as an alternative method when the proportional hazards assumption is not met. Genetic analyses including genetic correlation study and MR analysis and brain structure analyses were conducted to support our findings and explore the potential mechanisms. The study reveals the relationship between different smoking initiation periods and the onset time of dementia and shows that earlier smoking exposure has a more significant impact on dementia. It emphasizes the importance of preventing early smoking. In the future, more research focusing on the relationship between early exposure and dementia is called for to provide more detailed prevention measures for dementia that cover all age groups.

Longitudinal evolution of sleep disturbances in early multiple system atrophy: a 2-year prospective cohort study.

BACKGROUND: The progression of sleep disturbances remains unclear in patients with early multiple system atrophy (MSA). We aimed to explore the frequency, severity, and coexistence of 2-year longitudinal changes of sleep disturbances including REM sleep behavior disorder (RBD), excessive daytime sleepiness (EDS), and Parkinson's disease-related sleep problems (PD-SP) in early MSA. METHODS: MSA patients with a disease duration < 3 years were enrolled to complete a 2-year follow-up visit. Sleep disturbances including RBD, EDS, and PD-SP were assessed using the RBD Screening Questionnaire, Epworth sleepiness scale, and PD sleep scale-2, respectively. RESULTS: A total of 220 patients with MSA enrolled in the study and 90 patients completed the 2-year follow-up visit. The score of all three sleep disturbances significantly increased over the 2-year follow-up in MSA and MSA with the predominant parkinsonism group (all p < 0.05). The frequency of PD-SP (from 14.5 to 26.7%) and EDS (from 17.7 to 37.8%) was progressively increased (all p < 0.05) except for RBD (from 51.8 to 65.6%, p = 0.152) over the 2-year follow-up in MSA. The frequency of coexistence of two or three sleep disturbances also increased over time. The most common sleep disturbance was RBD, followed by EDS and PD-SP over the 2-year follow-up. CONCLUSIONS: The present study demonstrated that the frequency of different types of sleep disturbances progressively increased except for RBD and the coexistence of two or three sleep disturbances became more common over time in early MSA. Our study suggested that the assessment and management of sleep disturbances should begin early in MSA.

Plasma glial fibrillary acidic protein as a biomarker of disease progression in Parkinson's disease: a prospective cohort study.

BACKGROUND: Reactive astrogliosis has been demonstrated to have a role in Parkinson's disease (PD); however, astrocyte-specific plasma glial fibrillary acidic protein (GFAP)'s correlation with PD progression remains unknown. We aimed to determine whether plasma GFAP can monitor and predict PD progression. METHODS: A total of 184 patients with PD and 95 healthy controls (HCs) were included in this prospective cohort study and followed-up for 5 years. Plasma GFAP, amyloid-beta (Aß), p-tau181, and neurofilament light chain (NfL) were measured at baseline and at 1- and 2-year follow-ups. Motor and non-motor symptoms, activities of daily living, global cognitive function, executive function, and disease stage were evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS) part III, UPDRS-I, UPDRS-II, Montreal Cognitive Assessment (MoCA), Frontal Assessment Battery (FAB), and Hoehn and Yahr (H&Y) scales at each visit, respectively. RESULTS: Plasma GFAP levels were higher in patients with PD (mean [SD]: 69.80 [36.18], pg/mL) compared to HCs (mean [SD]: 57.89 [23.54], pg/mL). Higher levels of GFAP were observed in female and older PD patients. The adjusted linear mixed-effects models showed that plasma GFAP levels were significantly associated with UPDRS-I scores (ß: 0.006, 95% CI [0.001-0.011], p = 0.027). Higher baseline plasma GFAP correlated with faster increase in UPDRS-I (ß: 0.237, 95% CI [0.055-0.419], p = 0.011) and UPDRS-III (ß: 0.676, 95% CI [0.023-1.330], p = 0.043) scores and H&Y stage (ß: 0.098, 95% CI [0.047-0.149], p < 0.001) and faster decrease in MoCA (ß: - 0.501, 95% CI [- 0.768 to - 0.234], p < 0.001) and FAB scores (ß: - 0.358, 95% CI [- 0.587 to - 0.129], p = 0.002). Higher baseline plasma GFAP predicted a more rapid progression to postural instability (hazard ratio: 1.009, 95% CI [1.001-1.017], p = 0.033). CONCLUSIONS: Plasma GFAP might be a potential biomarker for monitoring and predicting disease progression in PD.

Cross-Ethnic Variant Screening and Burden Analysis of PTPA in Parkinson's Disease.

BACKGROUND: Recently, homozygous variants in PTPA were identified as the disease cause for two pedigrees with early-onset parkinsonism and intellectual disability. Although the initial link between PTPA and parkinsonism has been established, further replication was still necessary. OBJECTIVES: To evaluate the genetic role of PTPA in Parkinson's disease (PD). METHODS: We analyzed rare variants of PTPA in cohorts of Asian and European ancestries (Ncase = 2743, Ncontrol = 8177) with whole-exome sequencing, and further explored the functional effect of the target variant. RESULTS: One patient with early-onset PD from a consanguineous family carried the homozygous variant p.Met329Val, while her parents and elder sister with heterozygous p.Met329Val were healthy. This patient developed minor cognitive decline within 1 year, with a Montreal Cognitive Assessment (MoCA) score dropping from 28 to 25. Functional exploration with overexpression studies suggested that this variant was associated with decreased protein phosphatase 2A (PTPA) protein level by affecting protein stability, but not mRNA expression. CONCLUSIONS: These results have broadened the mutation spectrum of PTPA, and paved the way for further research into the role of PTPA in PD. © 2023 International Parkinson and Movement Disorder Society.

Lack of association of TP73 rare variants with amyotrophic lateral sclerosis in a Chinese cohort.

BACKGROUND: Recently, several rare variants of TP73 were identified as potential disease cause for amyotrophic lateral sclerosis (ALS) in the European population. However, further replication was still necessary, especially in cohorts with different ethnic backgrounds. METHODS: To explore the genetic role of TP73 in ALS in the Asian population, we analyzed the rare protein-coding variants in 2011 patients with ALS and 3298 controls with whole-exome sequencing. Fisher's exact test was performed between each variant and disease risk, while at gene level over-representation of rare variants in patients was examined with optimized sequence kernel association test. RESULTS: Totally 24 rare variants with minor allele frequency < 0.01 were identified, among which nine were absent in controls. One variant p.P335T was previously reported, and another three variants were in the same amino acids as the variants reported in previous studies (p.R36Q, p.R414Q, p.R78C). At gene level, rare variants of TP73 were not enriched in patients. CONCLUSIONS: Our findings did not support the genetic role of TP73 in ALS in the Chinese population. Replication of specific variants identified in patients from different cohorts might provide additional insight. The current results also broadened the mutation spectrum of TP73 and paved the way for further research.

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

BACKGROUND AND PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Our study expanded the genotypic spectrum of ALS patients with TBK1 variants and found that the clinical manifestations of TBK1 carriers are diverse.

Genetic analysis of and clinical characteristics associated with ANXA11 variants in a Chinese cohort with amyotrophic lateral sclerosis.

BACKGROUND: Variants in the annexin A11 gene (ANXA11) have been reported to be associated with amyotrophic lateral sclerosis (ALS). These variants may be involved in the pathogenesis of ALS by causing defects in intracellular protein trafficking. However, the genetic spectrum and clinical characteristics of ALS patients with ANXA11 variants are largely unknown. METHODS: Genetic analysis was performed on 1587 Chinese patients with ALS. Eight software packages were used to predict the deleteriousness of missense variants. In addition, we searched PubMed, Embase, and Web of Science for relevant literature and meta-analysed variant frequencies. RESULTS: In our ALS cohort, we identified 20 non-synonymous variants in 29 ALS patients, including one stop-gain, one frameshift, and 18 rare missense variants with seven predicted pathogenic variants. In a literature review of 11 reported studies that included 69 patients, 37 ANXA11 variants were reported, with a frequency of 1.7%, which was similar to that in our cohort (1.8%). Both our cohort and previous reports showed that ANXA11 carriers were more commonly males than females (12/17 vs. 19/31). Patients carrying ANXA11 variants affecting the C-terminal of the protein had earlier disease onset and shorter survival times than those carrying variants affecting the N-terminal. We found a relatively longer median survival time than that previously reported (53.6 months vs. 46.0 months). Additionally, Caucasian ANXA11 carriers were more likely to have cognitive impairment, typically frontotemporal dementia (FTD) than their Asian counterparts (20.0% vs. 14.3%). While more than half of the patients in our cohort had cognitive impairment, none had FTD. CONCLUSION: In our and previously published cases, ALS-associated ANXA11 variants predominantly affected the N- and C-terminal conserved domains. ANXA11 variant carriers are typically male and cognitively impaired. Our study extends the genotypic and phenotypic spectra of ALS patients with ANXA11 variants. Further expansion of the sample size is needed to analyse the clinical and non-motor symptom characteristics of patients and to deepen the understanding of the pathogenesis of ANXA11-associated ALS.

Mutation Screening of TFG in α-Synucleinopathy and Amyotrophic Lateral Sclerosis.

BACKGROUND: Recently, p.R383H in TFG was identified as the disease cause in a family with α-synucleinopathy and amyotrophic lateral sclerosis (ALS). However, no further replication has been conducted in larger cohorts. OBJECTIVE: The aim was to explore the genetic role of TFG in α-synucleinopathy and ALS. METHODS: We analyzed the rare protein-coding variants in patients with Parkinson's disease (PD), ALS, multiple system atrophy (MSA), spastic paraplegia (N = 2709), and 7536 controls with whole-exome sequencing. RESULTS: Nine rare variants were identified in PD and two in MSA. One PD patient carried the same variant p.R383H. Similarly, this patient developed early-onset PD with bradykinesia and rigidity on the left side as the initial symptoms. However, at the gene level, rare variants of TFG were not enriched in patients. CONCLUSIONS: Rare variants of TFG were not enriched in α-synucleinopathy and ALS. However, we could not deny the potential pathogenicity of specific variants such as p.R383H. Further exploration is still necessary. © 2022 International Parkinson and Movement Disorder Society.

Rare variant screening and burden analysis of PLXNA1 in Parkinson's disease.

BACKGROUND AND PURPOSE: Recently, p.Glu1121Ter in PLXNA1 was identified as a potential cause of parkinsonism. However, no further replication has been conducted in a wider range of Parkinson's disease (PD) cohorts. We aimed to evaluate the genetic role of PLXNA1 in PD. METHODS: We systematically analyzed the rare protein-coding variants (minor allele frequency [MAF] < 0.01) in 1080 patients and 1051 healthy controls. Fisher's exact test was used to analyze the associations between each variant and risk of PD, while, at gene level, over-representation of rare variants in patients was examined using the optimized sequence kernel association test (SKAT-O). RESULTS: In total, 43 rare variants were identified in PD. No variant was significantly associated with risk of PD. Burden analysis showed enrichment of ultra-rare variants (MAF < 0.001) of PLXNA1 in PD. One patient carried a variant (p.E1121D) in the same amino acid as that in the original study. Both patients showed worsened motor symptoms, and developed dyskinesia during follow-up. CONCLUSIONS: Our study explored the rare variant of PLXNA1 in PD, and paves the way for future research on the genetic role of PLXNA1 in PD.

Generation of induced pluripotent stem cell line LNDWCHi001-A from a patient with early-onset Parkinson's disease carrying the homozygous c.1898C > T (p. A633V) mutation in the PLA2G6 gene.

A variant of the phospholipase A2 group VI gene (PLA2G6, PARK14) has been found to cause early-onset Parkinson's disease (EOPD). In this study, we reprogrammed peripheral blood mononuclear cells from a 39-year-old patient with EOPD carrying a homozygous PLA2G6 mutation c.1898C > T (p. A633V) to generate the human induced pluripotent stem cell line LNDWCHi001-A. This cell line was identified based on pluripotent markers and displayed differentiation capacity, providing an essential model for studying the pathogenesis of EOPD and drug screening.

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.

Rare variant analysis of UQCRC1 in Chinese patients with early-onset Parkinson's disease.

Mitochondrial ubiquinol-cytochrome c reductase core protein 1 (UQCRC1) gene has been identified as a causative gene for autosomal dominant Parkinson's disease (PD), with the p.Y314S variant potentially associated with polyneuropathy in PD patients. The objectives of our study were to screen for UQCRC1 variants in Chinese patients with early-onset PD (EOPD) and explore the role of UQCRC1 in EOPD. We investigated the rare variants in 913 EOPD patients in our cohort using whole-exome sequencing, assessing their link to PD at both allele and gene levels. A total of 7 rare variants (minor allele frequency < 0.1%) of UQCRC1 were identified. However, no excessive burden of rare UQCRC1 variants was suggested in the EOPD patients. Further analysis with larger sample size and diverse regions is needed to determine the role of UQCRC1 in PD.

Genome-wide DNA methylation analysis related to ALS patient progression and survival.

BACKGROUND: Epigenetics contributes to the pathogenesis of amyotrophic lateral sclerosis (ALS). We aimed to characterize the DNA methylation profiles associated with clinical heterogeneity in disease progression and survival among patients. METHODS: We included a cohort of 41 patients with sporadic ALS, with a median follow-up of 86.9 months, and 27 rigorously matched healthy controls. Blood-based genome-wide DNA methylation analysis was conducted. RESULTS: A total of 948 progression rate-associated differentially methylated positions, 298 progression rate-associated differentially methylated regions (R-DMRs), 590 survival time-associated DMPs, and 197 survival time-associated DMRs (S-DMRs) were identified, using complementary grouping strategies. Enrichment analysis of differentially methylated genes highlighted the involvement of synapses and axons in ALS progression and survival. Clinical analysis revealed a positive correlation between the average methylation levels of the R-DMR in PRDM8 and disease progression rate (r = 0.479, p = 0.002). Conversely, there was an inverse correlation between the average methylation levels of the R-DMR in ANKRD33 and disease progression rate (r = - 0.476, p = 0.002). In addition, patients with higher methylation levels within the S-DMR of ZNF696 experienced longer survival (p = 0.016), while those with elevated methylation levels in the S-DMR of RAI1 had shorter survival (p = 0.006). CONCLUSION: DNA methylation holds promise as a potential biomarker for tracking disease progression and predicting survival outcome and also offers targets for precision medicine.

Clinical and genetic characteristics of ALS patients with variants in genes regulating DNA methylation.

BACKGROUND: Aberrant DNA methylation alterations are implicated in amyotrophic lateral sclerosis (ALS). Nevertheless, the influence of genetic variants in genes regulating DNA methylation on ALS patients is not well understood. Therefore, we aim to provide a comprehensive variant profile of genes related to DNA methylation (DNMT1, DNMT3A, DNMT3B, DNMT3L) and demethylation (TET1, TET2, TET3, TDG) and to investigate the association of these variants with ALS. METHODS: Variants were screened in a cohort of 2240 ALS patients from Southwest China, using controls from the Genome Aggregation Database (n = 9976) and the China Metabolic Analytics Project (n = 10,588). The over-representation of rare variants and their association with ALS risk were evaluated using Fisher's exact test with Bonferroni correction at both allele and gene levels. Kaplan-Meier analysis and Cox regression analysis were employed to explore the relationship between variants and survival. RESULTS: A total of 210 variants meeting the criteria were identified. Gene-based burden analysis identified a significant increase in ALS risk associated with rare variants in the TET2 gene (OR = 1.95, 95% CI = 1.29-2.88, P = 0.001). Survival analysis demonstrated that patients carrying variants in demethylation-related genes had a higher risk of death compared to those with methylation-related gene variants (HR = 1.29, 95% CI = 1.03-1.86, P = 0.039). CONCLUSIONS: This study provides a genetic variant profile of genes involved in DNA methylation and demethylation regulation, along with the clinical characteristics of ALS patients carrying these variants. The findings offer genetic evidence implicating disrupted DNA methylation dynamics in ALS.

Plasma GFAP as a prognostic biomarker of motor subtype in early Parkinson's disease.

Parkinson's disease (PD) is a heterogeneous movement disorder with different motor subtypes including tremor dominant (TD), indeterminate and postural instability, and gait disturbance (PIGD) motor subtypes. Plasma glial fibrillary acidic protein (GFAP) was elevated in PD patients and may be regarded as a biomarker for motor and cognitive progression. Here we explore if there was an association between plasma GFAP and different motor subtypes and whether baseline plasma GFAP level can predict motor subtype conversion. Patients with PD classified as TD, PIGD or indeterminate subtypes underwent neurological evaluation at baseline and 2 years follow-up. Plasma GFAP in PD patients and controls were measured using an ultrasensitive single molecule array. The study enrolled 184 PD patients and 95 control subjects. Plasma GFAP levels were significantly higher in the PIGD group compared to the TD group at 2-year follow-up. Finally, 45% of TD patients at baseline had a subtype shift and 85% of PIGD patients at baseline remained as PIGD subtypes at 2 years follow-up. Baseline plasma GFAP levels were significantly higher in TD patients converted to PIGD than non-converters in the baseline TD group. Higher baseline plasma GFAP levels were significantly associated with the TD motor subtype conversion (OR = 1.283, P = 0.033) and lower baseline plasma GFAP levels in PIGD patients were likely to shift to TD and indeterminate subtype (OR = 0.551, P = 0.021) after adjusting for confounders. Plasma GFAP may serve as a clinical utility biomarker in differentiating motor subtypes and predicting baseline motor subtypes conversion in PD patients.

Peripheral immunity relate to disease progression and prognosis in amyotrophic lateral sclerosis.

Background: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. Abnormalities in the peripheral immune system in ALS have been paid attention; however, the results of changes in peripheral immune parameters were inconsistent. Methods: A total of 1109 ALS patients were enrolled in the study. All patients received clinical evaluation and peripheral immune parameters measurement. The outcomes were analyzed by correlation analysis, multiple linear regression and cox survival analysis. Results: We found that ALS patients had significantly higher percentage of CD4+ T cells (39.3 vs. 37.1%, p < 0.001) and CD4+/CD8+ ratio (1.88 vs. 1.72, p = 0.011), significantly lower IgG (11.73 vs.12.82, p < 0.001) and IgA (2130.70 vs. 2284.8, p = 0.013) compared with the health controls. In the multivariate linear model, we found that each increase of 1.262, 0.278, and 4.44E-4 in ALSFRS-R scores were significantly associated with each increment of lymphocyte count, IgG, and IgA, respectively. However, each decrease of 0.341, 0.068, and 0.682 in ALSFRS-R score was associated with each increment in neutrophils, CD4+ T cells, and CD4+/CD8+ ratio, respectively. Cox survival regression analysis showed that the death risk of ALS patients was related to the levels of C3 (HR 0.592, 95% CI 0.361-0.973). Conclusion: We found that there were differences in peripheral immune parameters of ALS patients with the severity of the disease, especially neutrophil, lymphocyte, CD4+ T, and IgG; C3 is an independent predictor of survival in ALS patients. More studies are needed to elucidate the mechanisms associated with altered immune parameters in ALS.