Higher female prevalence of <i>C9orf72</i> hexanucleotide repeat expansions in ALS and <i>GRN</i> mutations in FTD suggest that sex-related risk factors might moderate <i>C9orf72</i> and <i>GRN-</i>mediated phenotypic expression.
In conclusion, serum NF-L in any ALS disease stage is a promising marker to support diagnosis and predict outcome, while serum PGRN and S100B are only of minor prognostic value.
We here demonstrate that cerebrospinal fluid progranulin levels do not correlate with its serum levels in AD, FTD and ALS, indicating a differential regulation of its central and peripheral levels in neurodegeneration.
The purpose of this meta-analysis was to investigate the association between progranulin polymorphism rs5848 and risk of the neurodegenerative diseases frontotemporal lobar degeneration (FTLD), Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS).
TBK1 LOF mutations are the third most frequent cause of clinical FTD in the Belgian clinically based patient cohort, after C9orf72 and GRN, and the second most common cause of clinical ALS after C9orf72.
Co-occurrence of the C9ORF72 expansion and a novel GRN mutation in a family with alternative expression of frontotemporal dementia and amyotrophic lateral sclerosis.
UBQLN2 was found to be a potent regulator of the levels of the FTD-linked secretory factor progranulin, possibly via the endosomal system, and ALS-linked mutations disturbed these functional consequences.
The vast majority of FTLD and ALS are characterized by the abnormal accumulation of TDP-43, including genetic forms associated with mutations in the genes C9ORF72, GRN, TARDBP and VCP.
A number of autosomal-dominant genes have been described that primarily cause ALS or FTLD such as progranulin (GRN), valosin-containing protein (VCP), and TAR DNA-Binding Protein (TARDBP), and for each of these conditions there are a small number of cases with both ALS and FTLD.
Substantial efforts have been deployed in the past decade to identify the genetic causes of amyotrophic lateral sclerosis (ALS), and we hypothesized here that mutations in SORT1 or aberrant SORT1 splicing reduce progranulin level and promote neurodegeneration.
A total of 76 subjects, including 56 with a clinical diagnosis of behavioural variant frontotemporal dementia and a mutation in one of these genes (19 with C9ORF72 mutations, 25 with tau mutations and 12 with progranulin mutations) and 20 sporadic subjects with behavioural variant frontotemporal dementia (including 50% with amyotrophic lateral sclerosis), with magnetic resonance imaging were included in this study.
More recently, progranulin gene mutations were recognized in association with the familial form of FTLD and a hexanucleotide repetition in C9ORF72 has been shown to be responsible for familial FTLD and amyotrophic lateral sclerosis.
Of potentially even greater importance it emerges that TDP-43 accumulation and inclusion formation characterises not only most sALS cases but also those that arise from mutations in several genes including TARDBP (predominantly ALS cases) itself, C9ORF72 (ALS and FTD cases), progranulin (predominantly FTD phenotypes), VAPB (predominantly ALS cases) and in some ALS cases with rare genetic variants of uncertain pathogenicity (CHMP2B).
In patients with ALS we identified 11 mutations, 5 of which were predicted to affect PGRN protein sequence or levels (four missense mutations and one 5' regulatory variant).
Direct sequencing analyses were performed in 19 genes, including ALS/frontotemporal lobar degeneration (FTLD)-related genes (SOD2, SOD3, ALS2/alsin, SMN1, PGRN, ANG, VEGF, VCP, VAPB, DCTN1, CHMP2B, and TARDBP or TDP-43), tauopathy-related gene (GSK3beta), and parkinsonism-related genes (alpha-synuclein, LRRK2, parkin, DJ-1, PINK1, and ATP13A2).
PGRN mutations were also identified in other neurodegenerative brain diseases such as amyotrophic lateral sclerosis and Alzheimer disease, though their biologic contribution to these diseases remains elusive.
First, mutations in the progranulin gene (PGRN) were recognized as a major cause of FTLD with ubiquitin-positive and tau-negative inclusions (FTLD-U), and subsequently the TAR DNA-binding protein-43 (TDP-43) was identified as a key protein within the ubiquitinated inclusions in FTLD-U and amyotrophic lateral sclerosis (ALS).