Dataset Information

Neurofilaments in pre-symptomatic ALS and the impact of genotype.

ABSTRACT: Objective. To evaluate serum and cerebrospinal fluid (CSF) levels of phosphorylated neurofilament heavy (pNfH), and to compare these to levels of neurofilament light (NfL), as biomarkers of pre-symptomatic ALS. Design. The study population includes 34 controls, 79 individuals at-risk for ALS, 22 ALS patients, and 14 phenoconverters. At-risk individuals are enrolled through Pre-Symptomatic Familial ALS (Pre-fALS), a longitudinal natural history and biomarker study of individuals who are carriers of any ALS-associated gene mutation, but who demonstrate no clinical evidence of disease at the time of enrollment. pNfH and NfL in serum and CSF were quantified using established enzyme-linked immunosorbent assays. Results. There is a longitudinal increase in serum pNfH in advance of the emergence of clinically manifest ALS. A similar pattern is observed for NfL, but with the absolute levels also frequently exceeding a normative threshold. Although CSF data are more sparse, similar patterns are observed for both neurofilaments, with absolute levels exceeding a normative threshold prior to phenoconversion. In serum, these changes are observed in the 6-12 months prior to disease among SOD1 A4V mutation carriers, and as far back as 2 and 3.5 years, respectively, in individuals with a FUS c.521del6 mutation and a C9ORF72 hexanucleotide repeat expansion. Conclusions. Serum and CSF pNfH increase prior to phenoconversion. In CSF, the temporal course of these changes is similar to NfL. In serum, however, pNfH is less sensitive to pre-symptomatic disease than NfL. The duration of pre-symptomatic disease, as defined by changes in neurofilaments, may vary depending on underlying genotype.

SUBMITTER: Benatar M

PROVIDER: S-EPMC6768722 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Neurofilaments in pre-symptomatic ALS and the impact of genotype.

Benatar Michael M Wuu Joanne J Lombardi Vittoria V Jeromin Andreas A Bowser Robert R Andersen Peter M PM Malaspina Andrea A

Amyotrophic lateral sclerosis & frontotemporal degeneration 20190821 7-8

Objective. To evaluate serum and cerebrospinal fluid (CSF) levels of phosphorylated neurofilament heavy (pNfH), and to compare these to levels of neurofilament light (NfL), as biomarkers of pre-symptomatic ALS. Design. The study population includes 34 controls, 79 individuals at-risk for ALS, 22 ALS patients, and 14 phenoconverters. At-risk individuals are enrolled through Pre-Symptomatic Familial ALS (Pre-fALS), a longitudinal natural history and biomarker study of i ...[more]

PMID: 31432691

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Project description:ObjectiveTo appraise the utility as biomarkers of blood antibodies and immune complexes to neurofilaments and dipeptide repeat proteins, the products of translation of the most common genetic mutation in amyotrophic lateral sclerosis (ALS).MethodsAntibodies and immune complexes against neurofilament light, medium, heavy chains as well as poly-(GP)-(GR) dipeptide repeats were measured in blood samples from the ALS Biomarkers (n = 107) and the phenotype-genotype biomarker (n = 129) studies and in 140 healthy controls. Target analyte levels were studied longitudinally in 37 ALS cases. Participants were stratified according to the rate of disease progression estimated before and after baseline and C9orf72 genetic status. Survival and longitudinal analyses were undertaken with reference to matched neurofilament protein expression.ResultsCompared to healthy controls, total neurofilament proteins and antibodies, neurofilament light immune complexes (p < 0.0001), and neurofilament heavy antibodies (p = 0.0061) were significantly elevated in ALS, patients with faster progressing disease (p < 0.0001) and in ALS cases with a C9orf72 mutation (p < 0.0003). Blood neurofilament light protein discriminated better ALS from healthy controls (AUC: 0.92; p < 0.0001) and faster from slower progressing ALS (AUC: 0.86; p < 0.0001) compared to heavy-chain antibodies and light-chain immune complexes (AUC: 0.79; p < 0.0001 and AUC: 0.74; p < 0.0001). Lower neurofilament heavy antibodies were associated with longer survival (Log-rank Chi-square: 7.39; p = 0.0065). Increasing levels of antibodies and immune complexes between time points were observed in faster progressing ALS.ConclusionsWe report a distinctive humoral response characterized by raising antibodies against neurofilaments and dipeptide repeats in faster progressing and C9orf72 genetic mutation carriers ALS patients. We confirm the significance of plasma neurofilament proteins in the clinical stratification of ALS.

Project description:Knowledge about the nature and timepoint of pathomolecular alterations preceding onset of symptoms in amyotrophic lateral sclerosis (ALS) is largely lacking. It could not only pave the way for valuable therapeutic targets but might also govern future concepts of pre-manifest disease modifying treatments. MicroRNAs (miRNAs) are central regulators of transcriptome plasticity and participate in pathogenic cascades and/or mirror cellular adaptation to insults. We obtained expression profiles of miRNAs as well as other non-coding RNAs (ncRNAs) in the serum of sporadic ALS patients (sALS), familial ALS cases (fALS), asymptomatic mutation carriers and healthy controls. We observed a strikingly homogenous ncRNA profile in fALS patients that, to a large extend, was independent to the underlying disease gene and different to heterogeneous ncRNA signatures in sALS patients. Moreover, we identified 68 significantly dysregulated ncRNAs in pre-manifest ALS mutation carriers, more than 20 years before the estimated time window of disease onset. 91% of ncRNA alterations in mutation carriers overlapped with the fALS patients revealing progressive changes towards and during the disease. Our data thus demonstrate a high epigenetic heterogeneity amongst sALS patients and suggest common denominators regarding molecular pathogenesis of different ALS genes. We describe the earliest pathomolecular alterations in ALS known to date, which provide a basis for the development of predictors of disease onset as well as the discovery of novel therapeutic targets and strongly argue for studies evaluating pre-symptomatic disease-modifying treatment in ALS. Serum ncRNA pofiles of sporadic and familiar ALS patients as well as asymptomatic ALS mutation carriers were compared to age and gender matched healthy controls using a total of 53 Affymetrix miRNA 3.0 arrays. In detail, a total of 9 fALS patients (analyzed in 6 arrays) were compared to 10 controls, a total of 18 ALS mutation carriers (analyzed in 12 arrays) were compared to 8 controls and 18 sALS patients were compared to 16 controls.

Project description:BackgroundImputation of partially missing or unobserved genotypes is an indispensable tool for SNP data analyses. However, research and understanding of the impact of initial SNP-data quality control on imputation results is still limited. In this paper, we aim to evaluate the effect of different strategies of pre-imputation quality filtering on the performance of the widely used imputation algorithms MaCH and IMPUTE.ResultsWe considered three scenarios: imputation of partially missing genotypes with usage of an external reference panel, without usage of an external reference panel, as well as imputation of completely un-typed SNPs using an external reference panel. We first created various datasets applying different SNP quality filters and masking certain percentages of randomly selected high-quality SNPs. We imputed these SNPs and compared the results between the different filtering scenarios by using established and newly proposed measures of imputation quality. While the established measures assess certainty of imputation results, our newly proposed measures focus on the agreement with true genotypes. These measures showed that pre-imputation SNP-filtering might be detrimental regarding imputation quality. Moreover, the strongest drivers of imputation quality were in general the burden of missingness and the number of SNPs used for imputation. We also found that using a reference panel always improves imputation quality of partially missing genotypes. MaCH performed slightly better than IMPUTE2 in most of our scenarios. Again, these results were more pronounced when using our newly defined measures of imputation quality.ConclusionEven a moderate filtering has a detrimental effect on the imputation quality. Therefore little or no SNP filtering prior to imputation appears to be the best strategy for imputing small to moderately sized datasets. Our results also showed that for these datasets, MaCH performs slightly better than IMPUTE2 in most scenarios at the cost of increased computing time.

Dataset Information

Neurofilaments in pre-symptomatic ALS and the impact of genotype.

Publications

Neurofilaments in pre-symptomatic ALS and the impact of genotype.

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