Article

VCP mutations are not a major cause of familial amyotrophic lateral sclerosis in the UK

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Abstract

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease causing loss of motor neurons in the spinal cord, brain stem and cerebral cortex. Mutations in the Valosin containing protein (VCP) gene have recently been identified in Familial ALS (FALS) patients, accounting for ~1% of all FALS cases. In order to study the frequency of VCP mutations in UK FALS patients, we have screened the exons known to harbour mutations together with 3' and 5' UTR sequences. No coding changes were identified in this UK cohort and no common polymorphisms were associated with FALS. However, we identified an imperfect hexanucleotide expansion (8 repeats), c.-221_-220insCTGCCACTGCCACTGCCG, in the 5'UTR of a FALS case and a 7-repeat hexanucleotide repeat in a Sporadic ALS case (SALS) that were not present in 219 UK controls. Subsequent screening of sequence data from 1844 controls (1000 genomes Phase 3) revealed the presence of the 7-repeat (0.3%) and a single individual with an 8-repeat containing a homogeneous insert [CTGCCG]3 but no individuals with the heterogeneous insert found in FALS ([CTGCCA]2[CTGCCG]). Two novel single base pair substitutions, c.-360G>C and c.2421+94C>T, were found in FALS cases in the 5' and 3' UTRs respectively. The hexanucleotide expansion and c.-360G>C were predicted to be pathogenic and were found in FALS cases harbouring C9orf72 expansions. The SALS case with a 7 repeat lacked a C9orf72 expansion. We conclude that VCP mutations are not a major cause of FALS in the UK population although novel rare variations in the 5' UTR of the VCP gene may be pathogenic. Copyright © 2015 Elsevier B.V. All rights reserved.

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... In fact, a number of additional mutated genes may co-occur with C9ORF72 repeat expansions, contributing to the pleiotropic clinical and pathological phenotypes observed in ALS, including the ALS-FTD spectrum [11]. These include mutations in superoxide dismutase 1 (SOD1), transcription of RNA activating protein/TAR DNA-binding protein (TARDBP), fused in sarcoma (FUS), optineurin (OPTN), ubiquilin-2 (UBQLN2), progranulin (PGRN), ataxin-2 (ATXN-2), valosincontaining protein (VCP), and dynactin (DCTN1), among others [11,54,[57][58][59][60][61][62][63][64]. Remarkably, mutations in these genes are per se bound to alterations of autophagy and the UPS, suggesting a possible mechanism through which they might add on the C9ORF72 expansion-related pathophysiology. ...
... This is largely bound to the recently-identified E3 ubiquitin ligase Hrd1, which increases the UPSdependent degradation and microtubule-dependent aggresome formation of OPTN [81]. Besides these genes, less frequent mutated genes such as ATXN-2, VCP, PGRN, and DCTN1 may concur with C9ORF72 in ALS [60][61][62][63], while potentiating alterations of cell-clearing systems, as discussed below [82][83][84][85] (Figure 2). ...
... Mutations in the ubiquitously-expressed valosin-containing protein (VCP) gene, which occur in ALS besides inclusion body myopathy (IBM) associated with Paget's disease of bone and FTD, lead to autophagy alterations and TDP-43-positive, ubiquitinated inclusions within both neurons and muscle cells [83]. Despite not being VCP mutations a major cause of ALS, pathogenic hexanucleotide expansions have been identified in the VCP 5'UTR of C9ORF72-ALS cases [62]. Since VCP is essential to autophagosome maturation both at baseline and during UPS inhibition [88], it is conceivable that a loss of VCP function might synergize with C9ORF72 expansions to occlude autophagy-dependent degradation of ubiquitinated proteins. ...
Article
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The coordinated activities of autophagy and the ubiquitin proteasome system (UPS) are key to preventing the aggregation and toxicity of misfold-prone proteins which manifest in a number of neurodegenerative disorders. These include proteins which are encoded by genes containing nucleotide repeat expansions. In the present review we focus on the overlapping role of autophagy and the UPS in repeat expansion proteotoxicity associated with chromosome 9 open reading frame 72 (C9ORF72) and androgen receptor (AR) genes, which are implicated in two motor neuron disorders, amyotrophic lateral sclerosis (ALS) and spinal-bulbar muscular atrophy (SBMA), respectively. At baseline, both C9ORF72 and AR regulate autophagy, while their aberrantly-expanded isoforms may lead to a failure in both autophagy and the UPS, further promoting protein aggregation and toxicity within motor neurons and skeletal muscles. Besides proteotoxicity, autophagy and UPS alterations are also implicated in neuromuscular junction (NMJ) alterations, which occur early in both ALS and SBMA. In fact, autophagy and the UPS intermingle with endocytic/secretory pathways to regulate axonal homeostasis and neurotransmission by interacting with key proteins which operate at the NMJ, such as agrin, acetylcholine receptors (AChRs), and adrenergic beta2 receptors (B2-ARs). Thus, alterations of autophagy and the UPS configure as a common hallmark in both ALS and SBMA disease progression. The findings here discussed may contribute to disclosing overlapping molecular mechanisms which are associated with a failure in cell-clearing systems in ALS and SBMA.
... Functional assessment using IBM functional rating scale (IBMFRS) [12] demonstrated a very low score of typically presents in 20s and 60s [8]. Other phenotypic features of VCP disease have been reported including Parkinson's disease, cardiomyopathy, hepatic steatosis, sensory-motor axonal neuropathy, and sphincter disturbance. ...
... Needle electromyography (EMG) of the muscles of the right arm, right leg, C5-T1, L2-S1, and right sternomastoid muscles showed fibrillation potentials in all the muscles. Motor units showed large amplitude, broad in the VCP gene [7,8,19,[21][22][23]. Although Tucker, et al. in 1984 [24] reported a family with typical combined lower motor neuron degeneration, and skeletal disorganization, the clinical spectrum associated with VCP mutations has recently been extended to include ALS [16,25]. ...
... TDP-43 and ubiquitinated proteins are the major component of inclusions characteristic of VCP-associated pathology, placing VCP disease in a novel category of neurodegenerative diseases termed TDP-43 proteinopathies [4,22]. Among the previously reported families with VCP mutations R159G, R159C, R159H, 191G, R191Q or D592N, ALS was the predominant phenotype and patients with I114V and D592N presented with pure ALS [8]. VCP gene mutations has been reported in families presenting with myopathy and/or PDB, FTD and other less common phenotypes [22]. ...
... The VCP protein has a variety of functions, as it is widely expressed. It is well known for roles in transporting misfolded proteins from the endoplasmic reticulum (ER) to be degraded by the proteasome [4,63]. Loss of VCP leads to a decrease in the production of cellular ATP [17]. ...
... Rare mutations (<1%) in VCP are known to cause FTD and familial ALS, and other diseases such as Charcot-Marie-Tooth type 2 disease, hereditary spastic paraplegia, inclusion body myopathy, and Paget's disease of the bone [64]. At least 24 different mutations have been identified so far [63]. In FTD, mutations in VCP are seen with TDP-43 proteinopathy. ...
... Mutations in the VCP gene are very rarely seen in FTD disease, and are associated with TDP-43 pathology. There are at least 24 mutations known to be associated with ALS and FTD/ALS [63,96]. The most common initial symptom is bvFTD (around 35%), and MND, with other initial symptoms being highly variable. ...
Article
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Many neurodegenerative diseases (NDDs) have been thought to be caused mainly by conditions that were not controlled by genetic inheritance. Extensive research into these diseases has recently discovered that perhaps a majority of them have genetic inheritance components. Once thought to be a rare form of NDD, frontotemporal degeneration (FTD) is now considered to be the main cause of early onset NDD, and the information on genetic causes and inheritance has increased dramatically over the last 10 years. The main genes that have been found to be involved in frontotemporal degeneration, MAPT, TARDBP, GRN C9orf72, VCP, FUS, and CHMP2B, have also been found in related diseases such as Alzheimer’s disease, Amyotrophic Lateral Sclerosis, and Parkinson’s disease. This paper is intended as an updated review of the genetic causes of FTD. This information should aid physicians and scientists in understanding the current concepts, and encourage even more genetic testing so that a full knowledge of genetic inheritance in FTD will be soon be forthcoming.
... [28] The identification of the remaining genes represents a substantial challenge, for which novel approaches are being explored. [29] Missense mutations in the gene encoding VCP have been associated with inclusion body myopathy associated with Paget's disease of bone and frontotemporal dementia, a dominant progressive disorder that maps to chromosome 9p21.1-p12. [30] VCP is associated with a variety of cellular activities, including cell cycle control, membrane fusion and the ubiquitin-proteasome degradation pathway, which may be the common pathogenic mechanism involved in all the associated disorders. ...
Article
Background: Osteoporosis and sarcopenia are important aspects of motor neuron disease (MND). Individuals with amyotrophic lateral sclerosis (MND-ALS) have an increased risk of falls and fractures. Currently, the standard of care does not involve a routine assessment of bone mineral density (BMD) and body composition in these patients. We aimed to assess BMD, bone mineral parameters and body composition in men with MND and compared them with healthy controls. Methods: Consecutive males between 50 and 80 years of age diagnosed as MND-ALS by revised El Escorial criteria and able to walk unassisted attending Neurology outpatient clinic were recruited into the study. Age, gender and body mass index (BMI) matched healthy controls were recruited from the local community. BMD and body composition were assessed by dual-energy x-ray absorptiometry (DXA). Bone mineral parameters and bone turnover markers (BTMs) were also assessed in them. Results: A total of 30 subjects with MND-ALS and 33 controls were recruited. The mean age (years) was 59.2 in cases and 61.2 in controls. The mean BMD (g/cm2) between the two groups was similar; however, BTMs were significantly higher in the MND group (P < 0.05). Subjects with MND-ALS had significantly lower mean appendicular lean mass (ALM) (19.9 versus 22.4 kg; P = 0.007) and ALM corrected for BMI than the healthy control group (0.858 versus 0.934 kg/kg/m2; P = 0.034). Sarcopenic obesity (Percentage fat mass >27% + ALM/BMI <0.786 kg/kg/m2) was more prevalent in MND-ALS compared to controls (44.5% versus 16.7%; P = 0.03). Conclusion: Although BMD was not significantly different between subjects with MND-ALS and healthy controls, BTMs were significantly higher in the MND group indicating a high bone turnover state. Sarcopenia and sarcopenic obesity were also more in MND-ALS group than controls. Routine assessment for bone health parameters and body composition indices may be included in management of the patients with MND.
... VCP's role in protein degradation and autophagy is implicated in the pathogenesis of IBMPFD, and may account for the protein aggregations/cytoplasmic inclusions observed in muscle, bone, and neuronal tissue [1,30]. Currently, over 50 mutations have been identified in VCP disease (Fig. 7A) [31][32][33][34][35][36]. Since our previous report of phenotype-genotype correlations [2], several other reports have expanded the phenotypic spectrum associated with VCP mutations to include Charcot-Marie-Tooth type 2 disease (CMT2) [10,37], Parkinson's disease [17], and anal incontinence [38]. ...
Article
Over fifty missense mutations in the gene coding for valosin-containing protein (VCP) are associated with a unique autosomal dominant adult onset progressive disease associated with combinations of proximo-distal inclusion body myopathy (IBM), Paget's disease of bone (PDB), frontotemporal dementia (FTD), and amyotrophic lateral sclerosis (ALS). We report the clinical, histological, and molecular findings in four new patients/families carrying novel VCP mutations: c.474 G>A (p.M158I); c.478 G>C (p.A160P); c.383G>C (p.G128A); and c.382G>T (p.G128C). Clinical features included myopathy, PDB, ALS and Parkinson's disease though frontotemporal dementia was not an associated feature in these families. One of the patients was noted to have severe manifestations of PDB and was suspected of having neoplasia. There was wide inter and intra-familial variation making genotype-phenotype correlations difficult between the novel mutations and frequency or age of onset of IBM, PDB, FTD, ALS and Parkinson's disease. Increasing awareness of the full spectrum of clinical presentations will improve diagnosis of VCP-related diseases and thus proactively manage or prevent associated clinical features such as PDB.
... Then, p.Asn91Tyr in the exon 3 of VCP were identified through exome sequencing performed in a Brazilian family presenting with the unusual intrafamiliar association of myopathy with rimmed vacuoles, ALS and FTD (Abrahao et al., 2016). Other studies performed in UK cohort failed to detect coding changes common polymorphisms associated with fALS (Kwok et al., 2015). Less frequently VCP variants has been identified in sALS. ...
Article
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Amyotrophic lateral sclerosis (ALS) is fatal neurodegenerative disease clinically characterized by upper and lower motor neuron dysfunction resulting in rapidly progressive paralysis and death from respiratory failure. Most cases appear to be sporadic, but 5-10 % of cases have a family history of the disease, and over the last decade, identification of mutations in about 20 genes predisposing to these disorders has provided the means to better understand their pathogenesis. Next Generation sequencing (NGS) is an advanced high-throughput DNA sequencing technology which have rapidly contributed to an acceleration in the discovery of genetic risk factors for both familial and sporadic neurological and neurodegenerative diseases. These strategies allowed to rapidly identify disease-associated variants and genetic risk factors for both familial (fALS) and sporadic ALS (sALS), strongly contributing to the knowledge of the genetic architecture of ALS. Moreover, as the number of ALS genes grows, many of the proteins they encode are in intracellular processes shared with other known diseases, suggesting an overlapping of clinical and phatological features between different diseases. To emphasize this concept, the review focuses on genes coding for Valosin-containing protein (VPC) and two Heterogeneous nuclear RNA-binding proteins (HNRNPA1 and hnRNPA2B1), recently idefied through NGS, where different mutations have been associated in both ALS and other neurological and neurodegenerative diseases.
... Mutations in at least 18 genes have been identified in familial ALS. Among them, p97 mutations account for less than 2% (Johnson et al., 2010;Koppers et al., 2012;Kwok et al., 2015). There are 18 reported mutations appearing in 12 different positions. ...
Article
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p97/VCP (known as Cdc48 in S. cerevisiae or TER94 in Drosophila) is one of the most abundant cytosolic ATPases. It is highly conserved from archaebacteria to eukaryotes. In conjunction with a large number of cofactors and adaptors, it couples ATP hydrolysis to segregation of polypeptides from immobile cellular structures such as protein assemblies, membranes, ribosome, and chromatin. This often results in proteasomal degradation of extracted polypeptides. Given the diversity of p97 substrates, this “segregase” activity has profound influence on cellular physiology ranging from protein homeostasis to DNA lesion sensing, and mutations in p97 have been linked to several human diseases. Here we summarize our current understanding of the structure and function of this important cellular machinery and discuss the relevant clinical implications.
... In these cases, more than one individual in the family develops ALS and sometimes family members have FTD as well. Mutations in at least 18 genes have been identified in FALS cases, with mutations in the p97 gene contributing <1-2% (Table 1) (Johnson et al., 2010;Koppers et al., 2012;Kwok et al., 2015). ...
Article
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A number of neurodegenerative diseases have been linked to mutations in the human protein p97, an abundant cytosolic AAA+ (ATPase associated with various cellular activities) ATPase, that functions in a large number of cellular pathways. With the assistance of a variety of cofactors and adaptor proteins, p97 couples the energy of ATP hydrolysis to conformational changes that are necessary for its function. Disease-linked mutations, which are found at the interface between two main domains of p97, have been shown to alter the function of the protein, although the pathogenic mutations do not appear to alter the structure of individual subunit of p97 or the formation of the hexameric biological unit. While exactly how pathogenic mutations alter the cellular function of p97 remains unknown, functional, biochemical and structural differences between wild-type and pathogenic mutants of p97 are being identified. Here, we summarize recent progress in the study of p97 pathogenic mutants.
... The Patient 2 presented with slow-variant, lower-motor neuron form of ALS, contrasting with the majority of reported cases who presented with both upper and lower motor neuron findings [6,18,57,58]. There was no personal history suggestive of FTD, although a formal cognitive test was not available to assess for subtle frontal impairment. ...
Article
Background: VCP (valosin-containing protein gene) variants have been associated with peripheral and central neurodegenerative processes, including inclusion body myopathy (IBM), Paget disease of bone (PDB), frontotemporal dementia (FTD), and familial amyotrophic lateral sclerosis (ALS) type 14. The combination of IBM, PDB (IBMPFD1) can presented in one individual. However, the association of IBMPFD1 and ALS in the same family is rare. Methods: We reported three individuals from a Brazilian kindred with intrafamilial phenotype variability. Whole exome sequencing (WES) of the proband was performed and revealed a novel VCP variant. VCP Sanger sequencing was performed in the proband and his family members to confirm WES finding and segregation. We performed a systematic review of the literature regarding the genotypic-phenotypic VCP correlations. Results: Each individual presented with either myopathy with rimmed vacuoles, ALS, or FTD. There was no PDB. WES of the proband identified the heterozygous variant c.271A>T (p.Asn91Tyr) in the exon 3 of VCP. Sanger sequencing confirmed the segregation of this variant in an autosomal-dominant pattern. Conclusion: This study expands the genotypic spectrum of the missense mutations of the VCP gene with a novel p.Asn91Tyr variant found in a Brazilian family presenting with the unusual intrafamiliar association of myopathy with rimmed vacuoles, ALS and FTD.
Article
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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.
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We analyzed a comprehensive set of single-nucleotide polymorphisms (SNPs) and length polymorphisms in the interferon regulatory factor 5 (IRF5) gene for their association with the autoimmune disease systemic lupus erythematosus (SLE) in 485 Swedish patients and 563 controls. We found 16 SNPs and two length polymorphisms that display association with SLE (P < 0.0005, OR > 1.4). Using a Bayesian model selection and averaging approach we identified parsimonious models with exactly two variants of IRF5 that are independently associated with SLE. The variants of IRF5 with the highest posterior probabilities (1.00 and 0.71, respectively) of being causal in SLE are a SNP (rs10488631) located 3' of IRF5, and a novel CGGGG insertion-deletion (indel) polymorphism located 64 bp upstream of the first untranslated exon (exon 1A) of IRF5. The CGGGG indel explains the association signal from multiple SNPs in the IRF5 gene, including rs2004640, rs10954213 and rs729302 previously considered to be causal variants in SLE. The CGGGG indel contains three or four repeats of the sequence CGGGG with the longer allele containing an additional SP1 binding site as the risk allele for SLE. Using electrophoretic mobility shift assays we show increased binding of protein to the risk allele of the CGGGG indel and using a minigene reporter assay we show increased expression of IRF5 mRNA from a promoter containing this allele. Increased expression of IRF5 protein was observed in peripheral blood mononuclear cells from SLE patients carrying the risk allele of the CGGGG indel. We have found that the same IRF5 allele also confers risk for inflammatory bowel diseases and multiple sclerosis, suggesting a general role for IRF5 in autoimmune diseases.
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Stress granules and P bodies are conserved cytoplasmic aggregates of nontranslating messenger ribonucleoprotein complexes (mRNPs) implicated in the regulation of mRNA translation and decay and are related to RNP granules in embryos, neurons, and pathological inclusions in some degenerative diseases. Using baker's yeast, 125 genes were identified in a genetic screen that affected the dynamics of P bodies and/or stress granules. Analyses of such mutants, including CDC48 alleles, provide evidence that stress granules can be targeted to the vacuole by autophagy, in a process termed granulophagy. Moreover, stress granule clearance in mammalian cells is reduced by inhibition of autophagy or by depletion or pathogenic mutations in valosin-containing protein (VCP), the human ortholog of CDC48. Because mutations in VCP predispose humans to amyotrophic lateral sclerosis, frontotemporal lobar degeneration, inclusion body myopathy, and multisystem proteinopathy, this work suggests that autophagic clearance of stress granule related and pathogenic RNP granules that arise in degenerative diseases may be important in reducing their pathology.
Article
Objective: To explore the putative connection between inclusion body myopathy, Paget disease, frontotemporal dementia (IBMPFD) and motor neuron disease (MND). Methods: Clinical, genetic, and EMG characterization of 17 patients from 8 IBMPFD families. Results: Limb weakness was the most common clinical manifestation (present in 15 patients, median onset age 38 years, range 25–52), with unequivocal evidence of upper motor neuron dysfunction in 3. EMG, abnormal in all 17, was purely neurogenic in 4, purely myopathic in 6, and mixed neurogenic/myopathic in 7. Cognitive/behavioral impairment was detected in at least 8. Mutations in VCP (R155H, R159G, R155C) were identified in 6 families, and in hnRNPA2B1 (D290V) in another family. The genetic cause in the eighth family has not yet been identified. Conclusion: Mutations in at least 4 genes may cause IBMPFD, and its phenotypic spectrum extends beyond IBM, Paget disease, and frontotemporal dementia (FTD). Weakness, the most common and dis- abling manifestation, may be caused by muscle disease or MND. The acronym IBMPFD is, therefore, insufficient to describe disorders due to VCP mutations or other recently identified IBMPFD-associated genes. Instead, we favor the descriptor multisystem proteinopathy (MSP), which encompasses both the extended clinical phenotype and the previously described prominent pathologic feature of protein aggregation in affected tissues. The nomenclature MSP1, MSP2, and MSP3 may be used for VCP-, HNRNPA2B1-, and HNRNPA1-associated disease, respectively. Genetic defects in MSP implicate a range of biological mechanisms including RNA processing and protein homeostasis, both with potential relevance to the pathobiology of more common MNDs such as amyotrophic lateral sclerosis (ALS) and providing an additional link between ALS and FTD. Neurology" 2013;80:1–7
Article
Objective: To identify the genetic variant that causes autosomal dominantly inherited motor neuron disease in a 4-generation Israeli-Arab family using genetic linkage and whole exome sequencing. Methods: Genetic linkage analysis was performed in this family using Illumina single nucleotide polymorphism chips. Whole exome sequencing was then undertaken on DNA samples from 2 affected family members using an Illumina 2000 HiSeq platform in pursuit of potentially pathogenic genetic variants that comigrate with the disease in this pedigree. Variants meeting these criteria were then screened in all affected individuals. Results: A novel mutation (p.R191G) in the valosin-containing protein (VCP) gene was identified in the index family. Direct sequencing of the VCP gene in a panel of DNA from 274 unrelated individuals with familial amyotrophic lateral sclerosis (FALS) revealed 5 additional mutations. Among them, 2 were previously identified in pedigrees with a constellation of inclusion body myopathy with Paget disease of the bone and frontotemporal dementia (IBMPFD) and in FALS, and 2 other mutations (p.R159C and p.R155C) in IBMPFD alone. We did not detect VCP gene mutations in DNA from 178 cases of sporadic amyotrophic lateral sclerosis. Conclusions: We report a novel VCP mutation identified in an amyotrophic lateral sclerosis family (p.R191G) with atypical clinical features. In our experience, VCP mutations arise in approximately 1.5% of FALS cases. Our study supports the view that motor neuron disease is part of the clinical spectrum of VCP-associated disease.
Article
Mutations in the valosin-containing-protein (VCP) gene are associated with the multidisorder disease, inclusion body myopathy with Pagets and associated frontotemporal dementia. This disease is characterized pathologically by large ubiquitinated, TAR DNA Binding Protein 43 (TDP-43) positive inclusions. These inclusions are also a common feature in neurological diseases including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTLD). Mutations in the VCP gene have been identified in ALS patients, therefore we aimed to characterize VCP variations in our own cohort of familial and sporadic ALS patients by sequencing all 17 coding exons of VCP. This study failed to detect any exonic variations in a subset of British familial and sporadic ALS patients.
Article
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the progressive loss of motor neurons in the motor cortex, brain stem and spinal cord. Mutations in the valosin-containing protein gene (VCP) were recently described in ALS families. Some of these families included diagnoses of other clinical features including frontotemporal dementia, Paget's disease, inclusion body myopathy, Parkinsonism and limb weakness. We sought to determine the prevalence of VCP mutations in Australian familial (n = 131) and sporadic (n = 48) ALS cohorts diagnosed with classic ALS. No mutations were identified indicating that VCP mutations are not a common cause of classic ALS among Australian cases with predominantly European ancestry.
Article
Mutations in valosin-containing protein (VCP) gene, already known to be associated with the multisystemic disorder, inclusion body myopathy with Paget's disease and frontotemporal dementia (IBMPFD), have been recently found also in familial cases of amyotrophic lateral sclerosis (ALS). To further define the frequency of VCP mutations in ALS Italian population, we screened a cohort of 166 familial ALS and 14 ALS-frontotemporal dementia (FTD) individuals. We identified a previously reported synonymous mutation (c.2093A>C; p.Q568Q), 2 intronic variants (c.1749-14C>T; c.2085-3C>T), and 1 nucleotide change (c.2814G>T) in the 3' untranslated region (UTR). Bioinformatical analyses predicted no changes in splicing process or microRNA binding sites. Our results do not confirm a main contribution of VCP gene to familial ALS in the Italian population.
Article
Mutations in the valosin-containing protein (VCP) gene were recently reported to be the cause of 1%-2% of familial amyotrophic lateral sclerosis (ALS) cases. VCP mutations are known to cause inclusion body myopathy (IBM) with Paget's disease (PDB) and frontotemporal dementia (FTD). The presence of VCP mutations in patients with sporadic ALS, sporadic ALS-FTD, and progressive muscular atrophy (PMA), a known clinical mimic of inclusion body myopathy, is not known. To determine the identity and frequency of VCP mutations we screened a cohort of 93 familial ALS, 754 sporadic ALS, 58 sporadic ALS-FTD, and 264 progressive muscular atrophy patients for mutations in the VCP gene. Two nonsynonymous mutations were detected; 1 known mutation (p.R159H) in a patient with familial ALS with several family members suffering from FTD, and 1 mutation (p.I114V) in a patient with sporadic ALS. Conservation analysis and protein prediction software indicate the p.I114V mutation to be a rare benign polymorphism. VCP mutations are a rare cause of familial ALS. The role of VCP mutations in sporadic ALS, if present, appears limited.
Article
The chromosome 9p21 amyotrophic lateral sclerosis-frontotemporal dementia (ALS-FTD) locus contains one of the last major unidentified autosomal-dominant genes underlying these common neurodegenerative diseases. We have previously shown that a founder haplotype, covering the MOBKL2b, IFNK, and C9ORF72 genes, is present in the majority of cases linked to this region. Here we show that there is a large hexanucleotide (GGGGCC) repeat expansion in the first intron of C9ORF72 on the affected haplotype. This repeat expansion segregates perfectly with disease in the Finnish population, underlying 46.0% of familial ALS and 21.1% of sporadic ALS in that population. Taken together with the D90A SOD1 mutation, 87% of familial ALS in Finland is now explained by a simple monogenic cause. The repeat expansion is also present in one-third of familial ALS cases of outbred European descent, making it the most common genetic cause of these fatal neurodegenerative diseases identified to date.
Article
Several families have been reported with autosomal-dominant frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), genetically linked to chromosome 9p21. Here, we report an expansion of a noncoding GGGGCC hexanucleotide repeat in the gene C9ORF72 that is strongly associated with disease in a large FTD/ALS kindred, previously reported to be conclusively linked to chromosome 9p. This same repeat expansion was identified in the majority of our families with a combined FTD/ALS phenotype and TDP-43-based pathology. Analysis of extended clinical series found the C9ORF72 repeat expansion to be the most common genetic abnormality in both familial FTD (11.7%) and familial ALS (23.5%). The repeat expansion leads to the loss of one alternatively spliced C9ORF72 transcript and to formation of nuclear RNA foci, suggesting multiple disease mechanisms. Our findings indicate that repeat expansion in C9ORF72 is a major cause of both FTD and ALS.
Article
Over the last couple of decades, there has been a growing body of clinical, genetic, and histopathological evidence that similar pathological processes underlie amyotrophic lateral sclerosis (ALS) and some types of frontotemporal lobe dementia (FTD). Even though there is great diversity in the genetic causes of these disorders, there is a high degree of overlap in their histopathology. Genes linked to rare cases of familial ALS and/or FTD, like FUS, TARDBP, OPTN, and UBQLN2 may converge onto a unifying pathogenic pathway and thereby provide novel therapeutic targets common to a spectrum of etiologically diverse forms of ALS and ALS-FTD. Additionally, there are major loci for ALS-FTD on chromosomes 9p and 15q. Identification of causative genetic alterations at those loci will be an important step in understanding the pathogenesis of juvenile- and adult-onset ALS and ALS-FTD. Interactions between TDP-43, FUS, optineurin, and ubiquilin 2 need to be studied to understand their common molecular pathways. Future efforts should also be directed towards generation and characterization of in vivo models to dissect the pathogenic mechanisms of these diseases. Such efforts will rapidly accelerate the discovery of new drugs that regulate accumulation of pathogenic proteins and their downstream consequences.
Article
The valosin containing protein (VCP) is a member of the AAA-ATPase family, a group of enzymatic molecular chaperones that have been associated with a range of cellular processes including ubiquitin-proteasome mediated degradation, membrane fusion, apoptosis, cell-cycle control, and autophagy.1 Mutations in VCP were first identified to cause familial inclusion body myopathy with early-onset Paget disease and frontotemporal dementia2 (IBMPFD) and more recently were found to be implicated in familial amyotrophic lateral sclerosis (ALS).3 It was suggested that VCP mutations may account for 1%–2% of familial ALS cases.3 Whether VCP mutations also contribute to sporadic ALS (SALS), however, has not yet been studied. Here, we report the identification of a novel p.Ile151Val mutation in VCP in a patient of African American descent with SALS.
Article
Using exome sequencing, we identified a p.R191Q amino acid change in the valosin-containing protein (VCP) gene in an Italian family with autosomal dominantly inherited amyotrophic lateral sclerosis (ALS). Mutations in VCP have previously been identified in families with Inclusion Body Myopathy, Paget disease, and Frontotemporal Dementia (IBMPFD). Screening of VCP in a cohort of 210 familial ALS cases and 78 autopsy-proven ALS cases identified four additional mutations including a p.R155H mutation in a pathologically proven case of ALS. VCP protein is essential for maturation of ubiquitin-containing autophagosomes, and mutant VCP toxicity is partially mediated through its effect on TDP-43 protein, a major constituent of ubiquitin inclusions that neuropathologically characterize ALS. Our data broaden the phenotype of IBMPFD to include motor neuron degeneration, suggest that VCP mutations may account for ∼1%-2% of familial ALS, and provide evidence directly implicating defects in the ubiquitination/protein degradation pathway in motor neuron degeneration.
Article
Inclusion body myopathy associated with Paget's disease of the bone and fronto-temporal dementia (IBMPFD) is a progressive autosomal dominant disorder caused by mutations in p97/VCP (valosin-containing protein). p97/VCP is a member of the AAA+ (ATPase associated with a variety of activities) protein family and participates in multiple cellular processes. One particularly important role for p97/VCP is facilitating intracellular protein degradation. p97/VCP has traditionally been thought to mediate the ubiquitin-proteasome degradation of proteins; however, recent studies challenge this dogma. p97/VCP clearly participates in the degradation of aggregate-prone proteins, a process principally mediated by autophagy. In addition, IBMPFD mutations in p97/VCP lead to accumulation of autophagic structures in patient and transgenic animal tissue. This is likely due to a defect in p97/VCP-mediated autophagosome maturation. The following review will discuss the evidence for p97/VCP in autophagy and how a disruption in this process contributes to IBMPFD pathogenesis.
Article
Mutations in the AAA+ protein (ATPase associated with a variety of cellular activities) p97/VCP (valosin-containing protein) cause a dominantly inherited syndrome of inclusion body myopathy with Paget's disease of the bone and fronto-temporal dementia (IBMPFD). p97/VCP is a ubiquitously expressed protein that participates in a number of cellular processes including endoplasmic reticulum-associated degradation (ERAD). p97/VCP aids in the extraction of ubiquitinated proteins from the endoplasmic reticulum (ER) and facilitates their delivery to the proteasome. This study focuses on the effects of disease-associated p97/VCP mutations on this pathway. We show that p97/VCP containing the most prevalent IBMPFD-associated mutation, R155H, has normal ATPase activity and hexameric structure. However, when expressed in cultured cells, both this and a second IBMPFD-associated p97/VCP mutant increase the overall level of ubiquitin-conjugated proteins and specifically impair degradation of mutant DeltaF508-CFTR handled by the ERAD pathway. These effects are similar to those previously described for an ATPase deficient p97/VCP mutant and suggest that IBMPFD mutations impair p97/VCP cellular function. In a subset of cells, IBMPFD mutations also promote formation of aggregates that contain p97/VCP, ubiquitin conjugates and ER-resident proteins. Undegraded mutant DeltaF508-CFTR also accumulates in these aggregates. We conclude that IBMPFD mutations in p97/VCP disrupt ERAD and that this may contribute to the pathogenesis of IBMPFD.
Article
Valosin-containing protein (VCP) is involved in a wide variety of cellular functions. Our previous studies showed that the enhanced expression of VCP in cancer cells correlated with invasion and metastasis of cancers. Here, the regulatory mechanism for VCP transcription was investigated. Luciferase reporter constructs containing serially deleted 5'-flanking region of the VCP gene were transfected into MCF7 mammary carcinoma cell line, in which VCP was abundantly expressed. The deletion and mutation at the two binding motifs for pre-B-cell leukemia transcription factor 1 (PBX1) reduced the luciferase activity, indicating that these two PBX1 motifs mediated the transactivation of the VCP gene. Chromatin immunoprecipitation assay showed the binding of PBX-1 to the 5'-flanking region of the VCP gene. The knockdown of PBX1 by siRNA decreased the expression level of VCP. VCP is reported to maintain cell viability after the treatment of tumor necrosis factor-alpha. The viability of tumor necrosis factor-alpha-treated cells was significantly reduced in PBX1 knockdown MCF7. These findings indicate that PBX1 plays a crucial role in VCP expression and function and that the PBX-VCP pathway might be important for cell survival under cytokine stress.
Article
Abnormal protein aggregates are commonly observed in affected neurons in many neurodegenerative disorders. We have reported that valosin-containing protein (VCP) co-localizes with protein aggregates in patients' neurons and in cultured cells expressing diseased proteins. However, the significance of such co-localization remains elucidated. Here we report the involvement of VCP in the re-solubilization process of abnormal protein aggregates. VCP recognized and accumulated onto pre-formed protein aggregates created by proteasome inhibition. VCP knockdown or the expression of dominant-negative VCP both significantly delayed the elimination of ubiquitin-positive aggregates. VCP was involved in the clearance of pre-formed polyglutamine aggregates as well. Paradoxically, VCP knockdown also diminished polyglutamine aggregate formation. Furthermore, its ATPase activity was required for the re-solubilization and re-activation of heat-denatured proteins, such as luciferase, from insoluble aggregates. We thus propose that VCP functions as a mediator for both aggregate formation and clearance depending upon the concentration of soluble aggregate-prone proteins, indicating dual VCP functions as an aggregate formase and an unfoldase.
Two coding changes (I114V and R159C) found in FALS have also been reported in SALS together with 3 further novel coding changes References
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Table S4). Two coding changes (I114V and R159C) found in FALS have also been reported in SALS together with 3 further novel coding changes References