Mutations in all five exons of SOD-1 may cause ALS

Analysis of SOD1 Variants in Chinese Patients with Familial Amyotrophic Lateral Sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease, and genetic contributors exert a significant role in the complicated pathogenesis. Identification of the genetic causes in ALS families could be valuable for early diagnosis and management. The development of potential drugs for patients with genetic defects will shed new light on ALS therapy.

AIM

To identify causative variants in three Chinese families with familial ALS (FALS), reveal the pathogenic mechanism, and look for the targeted drug for ALS.

DESIGN AND METHODS

Whole-exome sequencing and bioinformatics were used to perform genetic analysis of the ALS families. Functional analysis was performed to study the variants' function and search for potential drug targets.

RESULTS

Three heterozygous missense variants of the SOD1 gene were identified in families with FALS. The clinical manifestations of these patients include spinal onset, predominant lower motor neurons presentation, and absence of cognitive involvement. Functional analysis showed that all three SOD1 variants led to increased reactive oxygen species (ROS) levels, reduced cell viability, and formation of cytoplasmic aggregates. Remarkably, the decreased cell viability induced by variants was rescued after treatment with the ROS inhibitor N-acetylcysteine.

CONCLUSIONS

This study identified three SOD1 variants in three families with FALS. The variant SOD1 toxicity was associated with oxidative damage and aggregation, and N-acetylcysteine could rescue the decreased cell viability induced by these variants. Our findings support a pathogenic role for ROS in SOD1 deficiencies, and provide a potential drug N-acetylcysteine for ALS therapy, especially in SOD1-patients with limb onset.

The SOD1-mediated ALS phenotype shows a decoupling between age of symptom onset and disease duration

Superoxide dismutase (SOD1) gene variants may cause amyotrophic lateral sclerosis, some of which are associated with a distinct phenotype. Most studies assess limited variants or sample sizes. In this international, retrospective observational study, we compare phenotypic and demographic characteristics between people with SOD1-ALS and people with ALS and no recorded SOD1 variant. We investigate which variants are associated with age at symptom onset and time from onset to death or censoring using Cox proportional-hazards regression. The SOD1-ALS dataset reports age of onset for 1122 and disease duration for 883 people; the comparator population includes 10,214 and 9010 people respectively. Eight variants are associated with younger age of onset and distinct survival trajectories; a further eight associated with younger onset only and one with distinct survival only. Here we show that onset and survival are decoupled in SOD1-ALS. Future research should characterise rarer variants and molecular mechanisms causing the observed variability.

Mitochondria Dysfunction in Frontotemporal Dementia/Amyotrophic Lateral Sclerosis: Lessons From Drosophila Models

Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are neurodegenerative disorders characterized by declining motor and cognitive functions. Even though these diseases present with distinct sets of symptoms, FTD and ALS are two extremes of the same disease spectrum, as they show considerable overlap in genetic, clinical and neuropathological features. Among these overlapping features, mitochondrial dysfunction is associated with both FTD and ALS. Recent studies have shown that cells derived from patients' induced pluripotent stem cells (iPSC)s display mitochondrial abnormalities, and similar abnormalities have been observed in a number of animal disease models. Drosophila models have been widely used to study FTD and ALS because of their rapid generation time and extensive set of genetic tools. A wide array of fly models have been developed to elucidate the molecular mechanisms of toxicity for mutations associated with FTD/ALS. Fly models have been often instrumental in understanding the role of disease associated mutations in mitochondria biology. In this review, we discuss how mutations associated with FTD/ALS disrupt mitochondrial function, and we review how the use of Drosophila models has been pivotal to our current knowledge in this field.

Connecting RNA-Modifying Similarities of TDP-43, FUS, and SOD1 with MicroRNA Dysregulation Amidst A Renewed Network Perspective of Amyotrophic Lateral Sclerosis Proteinopathy

Beyond traditional approaches in understanding amyotrophic lateral sclerosis (ALS), multiple recent studies in RNA-binding proteins (RBPs)-including transactive response DNA-binding protein (TDP-43) and fused in sarcoma (FUS)-have instigated an interest in their function and prion-like properties. Given their prominence as hallmarks of a highly heterogeneous disease, this prompts a re-examination of the specific functional interrelationships between these proteins, especially as pathological SOD1-a non-RBP commonly associated with familial ALS (fALS)-exhibits similar properties to these RBPs including potential RNA-regulatory capabilities. Moreover, the cytoplasmic mislocalization, aggregation, and co-aggregation of TDP-43, FUS, and SOD1 can be identified as proteinopathies akin to other neurodegenerative diseases (NDs), eliciting strong ties to disrupted RNA splicing, transport, and stability. In recent years, microRNAs (miRNAs) have also been increasingly implicated in the disease, and are of greater significance as they are the master regulators of RNA metabolism in disease pathology. However, little is known about the role of these proteins and how they are regulated by miRNA, which would provide mechanistic insights into ALS pathogenesis. This review seeks to discuss current developments across TDP-43, FUS, and SOD1 to build a detailed snapshot of the network pathophysiology underlying ALS while aiming to highlight possible novel therapeutic targets to guide future research.

A novel p.N66T mutation in exon 3 of the SOD1 gene: report of two families of ALS patients with early cognitive impairment

Introduction: To date more than 180 different mutations in the SOD1 gene have been described in ALS; some of these mutations are associated to peculiar clinical features and have contributed to the understanding of disease heterogeneity. Only 5% of SOD1 mutations involve exon 3. Here we report a novel mutation c.197A > C in the exon 3 of the SOD1 gene in two apparently unrelated ALS families with early respiratory and cognitive impairment.Case report: In the first family two brothers developed ALS in their seventies, with arm weakness followed by bulbar involvement and behavioral breakdown. An unrelated 57-year-old man presented with progressive leg weakness and mild compromised executive functions without known family history for ALS/FTD and underwent invasive ventilation in a few months. A novel missense mutation A to C at codon 197 in exon 3 causing aminoacid substitution of arginine by threonine (N66T) was found for all of them. Harmful consequences of c.197A > C mutation on SOD1 function were suggested by in silico prediction and homology with other known mutations at the same position.Discussion and conclusion: Here, we report two apparently unrelated ALS families carrying a novel SOD1 mutation (N66T), supporting its pathogenic role by primary analysis, and characterized by early bulbar, respiratory, and cognitive involvement. Early cognitive impairment has been rarely described in ALS caused by SOD1 mutations, and mainly in the later phases of the disease. This report provides additional data on the SOD1 mutation spectrum and clinical presentation of ALS, widening phenotypical characterization of SOD1 ALS.

Osmolytes ameliorate the effects of stress in the absence of the heat shock protein Hsp104 in Saccharomyces cerevisiae

Aggregation of the prion protein has strong implications in the human prion disease. Sup35p is a yeast prion, and has been used as a model protein to study the disease mechanism. We have studied the pattern of Sup35p aggregation inside live yeast cells under stress, by using confocal microscopy, fluorescence activated cell sorting and western blotting. Heat shock proteins are a family of proteins that are produced by yeast cells in response to exposure to stressful conditions. Many of the proteins behave as chaperones to combat stress-induced protein misfolding and aggregation. In spite of this, yeast also produce small molecules called osmolytes during stress. In our work, we tried to find the reason as to why yeast produce osmolytes and showed that the osmolytes are paramount to ameliorate the long-term effects of lethal stress in Saccharomyces cerevisiae, either in the presence or absence of Hsp104p.

Dysregulation of Myosin Complex and Striated Muscle Contraction Pathway in the Brains of ALS-SOD1 Model Mice

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal disease characterized by cortical and spinal motor neuron degeneration, some inherited cases of which are caused by mutations in the gene coding for copper-zinc superoxide dismutase-1 (SOD1). The SOD1^G93A mutant model mouse, which expresses large amounts of mutant SOD1, develops adult-onset neurodegeneration of spinal motor neurons and progressive motor deficits leading to paralysis. We used the Tandem Mass Tag technique to investigate the proteome profile of hippocampus, cerebral cortex, and medulla oblongata of the SOD1^G93A mutant model mice as compared with that of wild-type (WT) mice. Fifteen proteins were significantly increased or decreased (i.e., changed) in all three tissues. Gene ontology analysis revealed that the changed proteins were mainly enriched in negative regulation of reactive oxygen species, myosin complex and copper ion binding. In the Striated Muscle Contraction Pathway, most of the identified proteins were decreased in the SOD1^G93A mice compared with the WT mice. Myosin-1 (MYH1), fructose-2,6-bisphosphatase TIGAR (TIGAR), and sarcoplasmic/endoplasmic reticulum calcium ATPase 1 (ATP2A1) were significantly reduced in mutant vs WT mice, as confirmed by Western blot analysis. Since myosins and tropomyosins are specific for synapse function and drive actin dynamics in the maturation of dendritic spines, changes in these proteins may contribute to perturbations of brain neuronal circuitry in addition to spinal motor neuron disease.

Genetic testing and reproductive choice in neurological disorders

Genetic testing is increasingly important for investigating suspected inherited neurological conditions. A genetic diagnosis can have a huge impact on patients and also their families. It is important for neurologists to appreciate the presymptomatic and prenatal testing options available to patients and their at-risk relatives once a genetic disorder is diagnosed. Asymptomatic family members can experience considerable psychological distress from the knowledge that they might have inherited a neurodegenerative condition. They may also be concerned about the risk of their children inheriting the condition. Information on reproductive options can provide hope and reassurance. This paper reviews the principles of genetic testing in neurological practice, and how they can be applied in prenatal and preimplantation genetic diagnosis. We explain the basis for direct and exclusion testing, use case examples to illustrate the process by which families are counselled and discuss the ethical implications of reproductive technologies.

Analysis of SOD1 mutations in a Chinese population with amyotrophic lateral sclerosis: a case-control study and literature review

Although the copper/zinc superoxide dismutase-1 (SOD1) gene has been identified in both familial ALS (FALS) and sporadic ALS (SALS), it has rarely been studied in Chinese patients with ALS, and there are few studies with large samples. This study sought to assess the prevalence of SOD1 mutations in Chinese ALS patients. We screened a cohort of 499 ALS patients (487 SALS and 12 FALS) from the Department of Neurology at the West China Hospital of Sichuan University and analyzed all coding exons of SOD1 by Sanger sequencing. In addition, we reviewed the mutation frequencies of common ALS causative genes in Chinese populations. Eight missense mutations in SOD1 were found in 8 ALS individuals: two novel mutations (p.G73D and p.V120F) and six previously reported mutations. The frequencies of SOD1 mutations were 1.03% (5/487) in SALS and 25% (3/12) in FALS from Southwest China. A literature review indicated that the mutation rates of major ALS causative genes were 53.55% in FALS and 6.29% in SALS. In Chinese SALS and FALS, the highest mutation frequency was in the SOD1 gene. Our results suggest that SOD1 mutation is the most common cause of ALS in Chinese populations and that the mutation spectrum of ALS varies among different ethnic populations.

De novo FUS mutations are the most frequent genetic cause in early-onset German ALS patients

In amyotrophic lateral sclerosis (ALS) patients with known genetic cause, mutations in chromosome 9 open reading frame 72 (C9orf72) and superoxide dismutase 1 (SOD1) account for most familial and late-onset sporadic cases, whereas mutations in fused in sarcoma (FUS) can be identified in just around 5% of familial and 1% of overall sporadic cases. There are only few reports on de novo FUS mutations in juvenile ALS patients. To date, no systematic evaluation on the frequency of de novo FUS mutations in early-onset ALS patients has been conducted. Here, we screened a cohort of 14 early-onset sporadic ALS patients (onset age <35 years) to determine the frequency of mutations in C9orf72, SOD1, and FUS in this defined patient cohort. All patients were recruited prospectively by a single center in a period of 38 months. No mutations were detected in SOD1 or C9orf72; however, we identified 6 individuals (43%) carrying a heterozygous FUS mutation including 1 mutation that has not been described earlier (c.1504delG [p.Asp502Thrfs*27]). Genetic testing of parents was possible in 5 families and revealed that the mutations in these patients arose de novo. Three of the 6 identified patients presented with initial bulbar symptoms. Our study identifies FUS mutations as the most frequent genetic cause in early-onset ALS. Genetic testing of FUS thus seems indicated in sporadic early-onset ALS patients especially if showing predominant bulbar symptoms and an aggressive disease course.

Amyotrophic lateral sclerosis in a patient with a family history of huntington disease: genetic counseling challenges

Amyotrophic lateral sclerosis (ALS) and Huntington disease (HD) are generally considered to be distinct and easily differentiated neurologic conditions. However, there are case reports of the co-occurrence of ALS with HD. We present a 57-year-old male with a clinical diagnosis of sporadic ALS in the context of a family history of HD. This case adds to the limited literature regarding individuals with a family history of HD who present with features of ALS. There were several genetic counseling challenges in counseling this patient including the diagnostic consideration of two fatal conditions, complex risk information, the personal and familial implications, and the patient's inability to communicate verbally or through writing due to disease progression. DNA banking effectively preserved the right of our patient and his wife not to learn his HD genetic status during a stressful time of disease progression while providing the option for family members to learn this information in the future if desired. We present lessons learned and considerations for other clinical genetics professionals who are presented with similar challenging issues.

Amyotrophic lateral sclerosis in pregnancy is associated with a vascular endothelial growth factor promoter genotype

BACKGROUND AND PURPOSE

The occurrence of amyotrophic lateral sclerosis (ALS) during pregnancy is uncommon and the effect of one on the other is not well described.

METHODS

The clinical and genetic features of five cases of ALS are reported with an onset during pregnancy or within 1 month from delivery. Charts from 239 women with a diagnosis of ALS attending the neuromuscular clinics at the Neuromuscular Omnicentre (NEMO) and at IRCCS Policlinico San Donato from 2008 to 2011 were reviewed.

RESULTS

Of these, 12.8% of the women in child-bearing age had a diagnosis of ALS during pregnancy or immediately after delivery. Genetic screening of the major causative genes revealed two mutations in superoxide dismutase 1 (SOD1) gene; the analysis of vascular endothelial growth factor (VEGF) promoter variation showed a segregation of the haplotype CA/AG (-2578C/A; -1190A/G) in patients developing ALS related to pregnancy. No effects on foetal development or neonatal course were observed.

CONCLUSIONS

Pregnancy may unmask ALS but whether this is coincidental is unclear. Hormonal and inflammatory modifications might trigger ALS in subjects with increased susceptibility to oxidative stress related to the toxic function of SOD1 or in subjects with a reduction of neuroprotective molecules such as VEGF.

2D gel blood serum biomarkers reveal differential clinical proteomics of the neurodegenerative diseases

This review addresses the challenges of neuroproteomics and recent progress in biomarkers and tests for neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. The review will discuss how the application of quantitative 2D gel electrophoresis, combined with appropriate single-variable and multivariate biostatistics, allows for selection of disease-specific serum biomarkers. It will also address how the use of large cohorts of specifically targeted patient blood serum samples and complimentary age-matched controls, in parallel with the use of selected panels of these biomarkers, are being applied to the development of blood tests to specifically address unmet pressing needs in the differential diagnosis of these diseases, and to provide potential avenues for mechanism-based drug targeting and treatment monitoring. While exploring recent findings in this area, the review discusses differences in critical pathways of immune/inflammation and amyloid formation between Parkinson's disease and amyotrophic lateral sclerosis, as well as discernable synergistic relationships between these pathways that are revealed by this approach. The potential for pathway measurement in blood tests for differential diagnosis, disease burden and therapeutic monitoring is also outlined.

ALS mutant FUS disrupts nuclear localization and sequesters wild-type FUS within cytoplasmic stress granules

Mutations in the gene encoding Fused in Sarcoma (FUS) cause amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. FUS is a predominantly nuclear DNA- and RNA-binding protein that is involved in RNA processing. Large FUS-immunoreactive inclusions fill the perikaryon of surviving motor neurons of ALS patients carrying mutations at post-mortem. This sequestration of FUS is predicted to disrupt RNA processing and initiate neurodegeneration. Here, we demonstrate that C-terminal ALS mutations disrupt the nuclear localizing signal (NLS) of FUS resulting in cytoplasmic accumulation in transfected cells and patient fibroblasts. FUS mislocalization is rescued by the addition of the wild-type FUS NLS to mutant proteins. We also show that oxidative stress recruits mutant FUS to cytoplasmic stress granules where it is able to bind and sequester wild-type FUS. While FUS interacts with itself directly by protein-protein interaction, the recruitment of FUS to stress granules and interaction with PABP are RNA dependent. These findings support a two-hit hypothesis, whereby cytoplasmic mislocalization of FUS protein, followed by cellular stress, contributes to the formation of cytoplasmic aggregates that may sequester FUS, disrupt RNA processing and initiate motor neuron degeneration.

Screening of the SOD1, FUS, TARDBP, ANG, and OPTN mutations in Korean patients with familial and sporadic ALS

About 5% of amyotrophic lateral sclerosis (ALS) cases are known to be familial (fALS) and mutations in SOD1 and other genes are found in more than 20% of fALS patients and in 2%-4% of apparently sporadic ALS (sALS) cases. However, there are few reports on the proportion of fALS and the frequency of mutations in Korean patients with ALS. We screened mutations in the SOD1, FUS, TARDBP, ANG, and OPTN genes in 258 consecutively enrolled Korean patients with ALS from October 2006 to November 2010. The frequency of fALS was estimated to be 3.5% (9/258), and mutations were identified in 88.9% (8/9) of fALS patients but only in 2.8% (7/249) of sALS patients. Seven fALS and 3 sALS patients had mutations in SOD1 gene while all the others had FUS gene. The proportion of fALS was lower than that reported in Caucasian populations but the frequency of SOD1 gene mutations in Korean fALS patients (77.8%, 7/9) was much higher than that reported in other ethnic groups. These findings might suggest that there is an ethnic difference in the proportion of fALS and the genetic background of ALS.

An MND/ALS phenotype associated with C9orf72 repeat expansion: abundant p62-positive, TDP-43-negative inclusions in cerebral cortex, hippocampus and cerebellum but without associated cognitive decline

The transactive response DNA binding protein (TDP-43) proteinopathies describe a clinico-pathological spectrum of multi-system neurodegeneration that spans motor neuron disease/amyotrophic lateral sclerosis (MND/ALS) and frontotemporal lobar degeneration (FTLD). We have identified four male patients who presented with the clinical features of a pure MND/ALS phenotype (without dementia) but who had distinctive cortical and cerebellar pathology that was different from other TDP-43 proteinopathies. All patients initially presented with weakness of limbs and respiratory muscles and had a family history of MND/ALS. None had clinically identified cognitive decline or dementia during life and they died between 11 and 32 months after symptom onset. Neuropathological investigation revealed lower motor neuron involvement with TDP-43-positive inclusions typical of MND/ALS. In contrast, the cerebral pathology was atypical, with abundant star-shaped p62-immunoreactive neuronal cytoplasmic inclusions in the cerebral cortex, basal ganglia and hippocampus, while TDP-43-positive inclusions were sparse. This pattern was also seen in the cerebellum where p62-positive, TDP-43-negative inclusions were frequent in granular cells. Western blots of cortical lysates, in contrast to those of sporadic MND/ALS and FTLD-TDP, showed high p62 levels and low TDP-43 levels with no high molecular weight smearing. MND/ALS-associated SOD1, FUS and TARDBP gene mutations were excluded; however, further investigations revealed that all four of the cases did show a repeat expansion of C9orf72, the recently reported cause of chromosome 9-linked MND/ALS and FTLD. We conclude that these chromosome 9-linked MND/ALS cases represent a pathological sub-group with abundant p62 pathology in the cerebral cortex, hippocampus and cerebellum but with no significant associated cognitive decline.

Anti-inflammatory effects of electroacupuncture in the respiratory system of a symptomatic amyotrophic lateral sclerosis animal model

BACKGROUND

Because amyotrophic lateral sclerosis (ALS) is a progressive inflammatory disease, treatment of the pulmonary system plays a key role in ALS patients' care. Previous studies have mainly examined the pathological mechanism of ALS in the central nervous system; however, there has been relatively little research regarding the pulmonary system in ALS animal models. In inflammatory diseases, including asthma and arthritis, electroacupuncture (EA) is commonly used for its anti-inflammatory effects. The goal of this study was to determine whether EA treatment affects inflammation in the pulmonary system in an ALS animal model.

METHODS

EA treatment at ST36 (Zusanli) acupoint was performed with 14-week-old hSOD1(G93A) transgenic mice. Immunohistochemical analysis was performed using anti-ionized calcium binding adaptor molecule 1 (Iba-1) and anti-tumor necrosis factor alpha (TNF-α) antibodies. To investigate the expression level of inflammatory proteins, Western blot analyses were performed using anti-Iba-1, anti-TNF-α, anti-nuclear factor kappa B (NF-κB), and anti-interleukin 6 (IL-6) antibodies. The activation of Ser435-phospho-specific RAC-alpha serine/threonine-protein kinase 1 (pAKT) and the increase of phosphorylated extracellular-signal-regulated kinases (pERK) protein in lung tissues of EA-treated and untreated hSOD1(G93A) mice were also evaluated by Western blot.

RESULTS

EA treatment decreased the expression of the proinflammatory proteins such as TNF-α and IL-6, pNF-κB, and Iba-1 and increased the level of activated pAKT and pERK compared to control hSOD1(G93A) mice.

CONCLUSIONS

Our findings suggest that EA could be an effective anti-inflammatory treatment for the respiratory impairment that occurs in ALS animal models.

Looking for differences in copy number between blood and brain in sporadic amyotrophic lateral sclerosis

INTRODUCTION

Most analyses of blood DNA in sporadic neuromuscular disorders have been inconclusive. This may be because some genetic variants occur only in brain tissue. We therefore looked for copy number variants (CNVs) in both blood and brain in patients with sporadic amyotrophic lateral sclerosis (SALS).

METHODS

Genome-wide CNVs were compared in blood and brain from 32 SALS patients and from 26 normal (control) brains, using Affymetrix 6.0 arrays.

RESULTS

There were 410 CNVs present in brain but not blood (somatic CNVs) in 94% of the patients (median 8 CNVs per patient). Twenty-four of the somatic CNVs were rare, were not found in control brains, and overlapped with genes.

CONCLUSIONS

Brain-specific CNVs may be common and appear to be present in a proportion of patients with SALS. The more detailed copy number analysis that is becoming available with massively parallel sequencing may uncover brain-specific CNVs that underlie some cases of SALS.

Impact of presymptomatic genetic testing for familial amyotrophic lateral sclerosis

PURPOSE

The Pre-familial Amyotrophic Lateral Sclerosis (Pre-fALS) study is a longitudinal study of individuals potentially at risk for developing familial amyotrophic lateral sclerosis. Our goals were to (1) explore participants' decisions of whether to learn results of presymptomatic testing or not; (2) understand the psychosocial impact of these decisions; and (3) assess preferences for receiving results by telephone or in person.

METHODS

The sample for this substudy comprised 20 participants drawn randomly from autosomal dominant mutant superoxide dismutase 1 families in the Pre-fALS study. Twenty participants completed a semistructured phone interview; prominent themes were identified and rated.

RESULTS

Fourteen participants chose to learn results; six had mutant superoxide dismutase 1 and eight had wild-type superoxide dismutase 1. Of the six who initially elected nondisclosure, three were reconsidering their decision. Regardless of the results and method of counseling, participants had adapted well, at least in the short term.

CONCLUSION

We recommend that (1) those considering presymptomatic genetic testing should undergo professional counseling to help decide whether to learn results; (2) discussion should include the option of telephone genetic counseling for those without easy access to in-person counseling; and (3) those who initially decline to learn results should be offered the opportunity to learn their mutation status as their decision evolves.

Amyotrophic lateral sclerosis: one or multiple causes?

The Amyotrophic lateral sclerosis (ALS) is the most common form of motor neuron disease in the adulthood, and it is characterized by rapid and progressive compromise of the upper and lower motor neurons. The majority of the cases of ALS are classified as sporadic and, until now, a specific cause for these cases still is unknown. To present the different hypotheses on the etiology of ALS. It was carried out a search in the databases: Bireme, Scielo and Pubmed, in the period of 1987 to 2011, using the following keywords: Amyotrophic lateral sclerosis, motor neuron disease, etiology, causes and epidemiology and its similar in Portuguese and Spanish. It did not have consensus as regards the etiology of ALS. Researches demonstrates evidences as regards intoxication by heavy metals, environmental and occupational causes, genetic mutations (superoxide dismutase 1), certain viral infections and the accomplishment of vigorous physical activity for the development of the disease. There is still no consensus regarding the involved factors in the etiology of ALS. In this way, new research about these etiologies are necessary, for a better approach of the patients, promoting preventive programs for the disease and improving the quality of life of the patients.

High-Resolution Melting (HRM) Analysis of the Cu/Zn Superoxide Dismutase (SOD1) Gene in Japanese Sporadic Amyotrophic Lateral Sclerosis (SALS) Patients

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder, and the majority of ALS are sporadic (SALS). Recently, several causative genes for familial ALS (FALS) were identified, but the cause of the SALS is still unknown. This time, we aimed to identify the genetic background of SALS. First, we applied the new sensitive screening methods: high-resolution melting (HRM) analysis. HRM analysis detected 18 out of 19 known SOD1 gene mutations (94.7% sensitivity). Next, we screened SOD1, three novel mutations (C6Y, Q22H, and S134T) were identified in our own 184 SALS cases (1.63% prevalence), and four mutations in another 255 SALS cases (1.56% prevalence) registered from all over Japan. The patients with SOD1 mutations suggested a relatively young onset and limb involvement at onset. The HRM analysis is a sensitive and easy screening method; we will use this method for screening other ALS causative genes and revealing the genetic background of SALS.

Clinical features and Cu/Zn superoxide dismutase gene mutations in two mainland Chinese families with amyotrophic lateral sclerosis

Clinical information of two families with amyotrophic lateral sclerosis (ALS) was studied and a mutation analysis of the SOD1 gene was performed using direct DNA sequencing. Two previously reported mutations of the SOD1 gene, G20T (Cys6Phe substitution), and G255C (Leu84Phe substitution), were identified and cosegregated with the disease in the two families. Patients with a Cys6Phe mutation demonstrated rapid disease progression with severe clinical phenotypes, and the patients with a Leu84Phe mutation had a variety of different clinical phenotypes. This is the third report of SOD1 gene mutations in Mainland Chinese patients with different ALS phenotypes. This supports the hypothesis that the clinical course of ALS may vary depending on the specific genetic mutation.

Abnormal sensitivity of cannabinoid CB1 receptors in the striatum of mice with experimental amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that primarily affects motor neurons. However, additional neuronal systems are also involved, and the aim of this study was to investigate the involvement of the nucleus striatum. By means of neurophysiological recordings in slices, we have investigated both excitatory and inhibitory synaptic transmission in the striatum of G93A-SOD1 ALS mice, along with the sensitivity of these synapses to cannabinoid CB1 receptor stimulation. We have observed reduced frequency of glutamate-mediated spontaneous excitatory postsynaptic currents (EPSCs) and increased frequency of GABA-mediated spontaneous inhibitory postsynaptic currents (IPSCs) recorded from striatal neurons of ALS mice, possibly due to presynaptic defects in transmitter release. The sensitivity of cannabinoid CB1 receptors controlling both glutamate and GABA transmission was remarkably potentiated in ALS mice, indicating that adaptations of the endocannabinoid system might be involved in the pathophysiology of ALS. In conclusion, our data identify possible physiological correlates of striatal dysfunction in ALS mice, and suggest that cannabinoid CB1 receptors might be potential therapeutic targets for this dramatic disease.

The epidemiology of CuZn-SOD mutations in Germany: a study of 217 families

We screened 217 patients from Germany (n = 213), Austria (n = 2) and Switzerland (n = 2) with a positive family history for amyotrophic lateral sclerosis (ALS) for mutations in the copper/zinc superoxide dismutase (SOD1) gene. We found that 13% of the families tested carried mutations. By analyzing inheritance, we detected a clear-cut co-segregation in 5 of the 28 families; however, in two families with an established mutation, co-segregation was absent. In Germany, the R115G mutation is comparatively frequent and exhibits a specific aggressive phenotype. The L144F mutation, which is the most prevalent mutation in the Balkan countries, and the D90A mutation which is the most frequent SOD1 mutation globally, seem to be the second most common disease-causing mutations in Germany.

Characterization of alternative isoforms and inclusion body of the TAR DNA-binding protein-43

TAR DNA-binding protein-43 (TDP-43) has been recently identified as a major component of the ubiquitinated inclusions found in frontotemporal lobar degeneration with ubiquitin-positive inclusions and in amyotrophic lateral sclerosis, diseases that are collectively termed TDP-43 proteinopathies. Several amyotrophic lateral sclerosis-linked mutations of the TDP-43 gene have also been identified; however, the precise molecular mechanisms underlying the neurodegeneration remain unclear. To investigate the biochemical characteristics of TDP-43, we examined truncation, isoforms, and cytoplasmic inclusion (foci) formation using TDP-43-expressing cells. Under apoptosis, caspase-3 generates two 35-kDa (p35f) and 25-kDa (p25f) fragments. However, in caspase-3(-/-) cells, novel caspase-3-independent isoforms of these two variants (p35iso and p25iso) were also detected under normal conditions. With a deletion mutant series, the critical domains for generating both isoforms were determined and applied to in vitro transcription/translation, revealing alternate in-frame translation start sites downstream of the natural initiation codon. Subcellular localization analysis indicated that p35 (p35f and p35iso) expression leads to the formation of stress granules, cellular structures that package mRNA and RNA-binding proteins during cell stress. After applying proteasome inhibitors, aggresomes, which are aggregates of misfolded proteins, were formed in the cytoplasm of cells expressing p35. Collectively, this study demonstrates that the 35-kDa isoforms of TDP-43 assemble in stress granules, suggesting that TDP-43 plays an important role in translation, stability, and metabolism of mRNA. Our findings provide new biological and pathological insight into the development of TDP-43 proteinopathies.

Amyotrophic lateral sclerosis (ALS): three letters that change the people's life. For ever

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting the motor nervous system. It causes progressive and cumulative physical disabilities in patients, and leads to eventual death due to respiratory muscle failure. The disease is diverse in its presentation, course, and progression. We do not yet fully understand the cause or causes of the disease, nor the mechanisms for its progression; thus, we lack effective means for treating this disease. Currently, we rely on a multidisciplinary approach to symptomatically manage and care for patients who have ALS. Although amyotrophic lateral sclerosis and its variants are readily recognized by neurologists, about 10% of patients are misdiagnosed, and delays in diagnosis are common. Prompt diagnosis, sensitive communication of the diagnosis, the involvement of the patient and their family, and a positive care plan are prerequisites for good clinical management. A multidisciplinary, palliative approach can prolong survival and maintain quality of life. Treatment with Riluzole improves survival but has a marginal effect on the rate of functional deterioration, whereas non-invasive ventilation prolongs survival and improves or maintains quality of life. In this Review, we discuss the diagnosis, management, and how to cope with impaired function and end of life on the basis of our experience, the opinions of experts, existing guidelines, and clinical trials. Multiple problems require a multidisciplinary approach including aggressive symptomatic management, rehabilitation to maintain motor function, nutritional support (enteric feeding, gastrostomy), respiratory support (non invasive home ventilation, invasive ventilation, tracheotomy), augmentative communication devices, palliative care, psychological support for both patients and families (because family members so often play a central role in management and care), communication between the care team, the patient and his or her family, and recognition of the clinical and social effects of cognitive impairment. Social, bioethical, and financial issues as well as advance directives should be addressed. A plethora of evidence-based guidelines should be compiled into an internationally agreed guideline of best practice. The multidisciplinary team has changed the history of disease, with still no curative therapy available.

Immature copper-zinc superoxide dismutase and familial amyotrophic lateral sclerosis

Mutations in human copper-zinc superoxide dismutase (SOD1) cause an inherited form of amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease, motor neuron disease). Insoluble forms of mutant SOD1 accumulate in neural tissues of human ALS patients and in spinal cords of transgenic mice expressing these polypeptides, suggesting that SOD1-linked ALS is a protein misfolding disorder. Understanding the molecular basis for how the pathogenic mutations give rise to SOD1 folding intermediates, which may themselves be toxic, is therefore of keen interest. A critical step on the SOD1 folding pathway occurs when the copper chaperone for SOD1 (CCS) modifies the nascent SOD1 polypeptide by inserting the catalytic copper cofactor and oxidizing its intrasubunit disulfide bond. Recent studies reveal that pathogenic SOD1 proteins coming from cultured cells and from the spinal cords of transgenic mice tend to be metal-deficient and/or lacking the disulfide bond, raising the possibility that the disease-causing mutations may enhance levels of SOD1-folding intermediates by preventing or hindering CCS-mediated SOD1 maturation. This mini-review explores this hypothesis by highlighting the structural and biophysical properties of the pathogenic SOD1 mutants in the context of what is currently known about CCS structure and action. Other hypotheses as to the nature of toxicity inherent in pathogenic SOD1 proteins are not covered.

SNP haplotype mapping in a small ALS family

The identification of genes for monogenic disorders has proven to be highly effective for understanding disease mechanisms, pathways and gene function in humans. Nevertheless, while thousands of Mendelian disorders have not yet been mapped there has been a trend away from studying single-gene disorders. In part, this is due to the fact that many of the remaining single-gene families are not large enough to map the disease locus to a single site in the genome. New tools and approaches are needed to allow researchers to effectively tap into this genetic gold-mine. Towards this goal, we have used haploid cell lines to experimentally validate the use of high-density single nucleotide polymorphism (SNP) arrays to define genome-wide haplotypes and candidate regions, using a small amyotrophic lateral sclerosis (ALS) family as a prototype. Specifically, we used haploid-cell lines to determine if high-density SNP arrays accurately predict haplotypes across entire chromosomes and show that haplotype information significantly enhances the genetic information in small families. Panels of haploid-cell lines were generated and a 5 centimorgan (cM) short tandem repeat polymorphism (STRP) genome scan was performed. Experimentally derived haplotypes for entire chromosomes were used to directly identify regions of the genome identical-by-descent in 5 affected individuals. Comparisons between experimentally determined and in silico haplotypes predicted from SNP arrays demonstrate that SNP analysis of diploid DNA accurately predicted chromosomal haplotypes. These methods precisely identified 12 candidate intervals, which are shared by all 5 affected individuals. Our study illustrates how genetic information can be maximized using readily available tools as a first step in mapping single-gene disorders in small families.

Mutations in FUS, an RNA processing protein, cause familial amyotrophic lateral sclerosis type 6

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that is familial in 10% of cases. We have identified a missense mutation in the gene encoding fused in sarcoma (FUS) in a British kindred, linked to ALS6. In a survey of 197 familial ALS index cases, we identified two further missense mutations in eight families. Postmortem analysis of three cases with FUS mutations showed FUS-immunoreactive cytoplasmic inclusions and predominantly lower motor neuron degeneration. Cellular expression studies revealed aberrant localization of mutant FUS protein. FUS is involved in the regulation of transcription and RNA splicing and transport, and it has functional homology to another ALS gene, TARDBP, which suggests that a common mechanism may underlie motor neuron degeneration.

Protein aggregation and protein instability govern familial amyotrophic lateral sclerosis patient survival

The nature of the "toxic gain of function" that results from amyotrophic lateral sclerosis (ALS)-, Parkinson-, and Alzheimer-related mutations is a matter of debate. As a result no adequate model of any neurodegenerative disease etiology exists. We demonstrate that two synergistic properties, namely, increased protein aggregation propensity (increased likelihood that an unfolded protein will aggregate) and decreased protein stability (increased likelihood that a protein will unfold), are central to ALS etiology. Taken together these properties account for 69% of the variability in mutant Cu/Zn-superoxide-dismutase-linked familial ALS patient survival times. Aggregation is a concentration-dependent process, and spinal cord motor neurons have higher concentrations of Cu/Zn-superoxide dismutase than the surrounding cells. Protein aggregation therefore is expected to contribute to the selective vulnerability of motor neurons in familial ALS.

Good practice in the management of amyotrophic lateral sclerosis: clinical guidelines. An evidence-based review with good practice points. EALSC Working Group

The evidence base for diagnosis and management of ALS is still weak, and curative therapy is lacking. Nonetheless, early diagnosis and symptomatic therapy can profoundly influence care and quality of life of the patient and relatives, and may increase survival time. This review addresses the current optimal clinical approach to ALS. The literature search is complete to December 2006. Where there was lack of evidence but consensus was clear we have stated our opinion as good practice points. We conclude that a diagnosis of ALS can be achieved by early examination by an experienced neurologist. The patient should be informed of the diagnosis by the consultant. Following diagnosis, a multi-diciplinary care team should support the patient and relatives. Medication with riluzole should be initiated as early as possible. PEG is associated with improved nutrition and should be inserted early. The operation is hazardous in patients with VC <50%: RIG may be a better alternative. Non-invasive positive pressure ventilation improves survival and quality of life but is underused in Europe. Maintaining the patient's ability to communicate is essential. During the course of the disease, every effort should be made to maintain patient autonomy. Advance directives for palliative end of life care are important and should be discussed early with the patient and relatives if they so wish.

Altered calcium homeostasis in motor neurons following AMPA receptor but not voltage-dependent calcium channels' activation in a genetic model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a late-onset progressive neurodegenerative disease characterized by a substantial loss of motor neurons in the spinal cord, brain stem and motor cortex. By combining electrophysiological recordings with imaging techniques, clearance/buffering capacity of cultured spinal cord motor neurons after a calcium accumulation has been analyzed in response to AMPA receptors' (AMPARs') activation and to depolarizing stimuli in a genetic mouse model of ALS (G93A). Our studies demonstrate that the amplitude of the calcium signal in response to AMPARs' or voltage-dependent calcium channels' activation is not significantly different in controls and G93A motor neurons. On the contrary, in G93A motor neurons, the [Ca(2+)](i) recovery to basal level is significantly slower compared to control neurons following AMPARs but not voltage-dependent calcium channels' activation. This difference was not observed in G93A cultured cortical neurons. This observation is the first to indicate a specific alteration of the calcium clearance linked to AMPA receptors' activation in G93A motor neurons and the involvement of AMPA receptor regulatory proteins controlling both AMPA receptor functionality and the sequence of events connected to them.

Red cell superoxide dismutase activity in sporadic amyotrophic lateral sclerosis

Specific biologic markers are not available for definitive diagnosis and monitoring of disease progression in sporadic amyotrophic lateral sclerosis (SALS). Oxidative stress plays a role in ALS pathogenesis. The purpose of this study was to determine the association between Cu/Zn superoxide dismutase (SOD1) activity, diagnosis and prognosis. The present study included 25 SALS patients (SALS group; age 51+/-12 years) and 10 healthy subjects (age 45+/-5 years) as a control group. Patients were divided into groups representing four levels of diagnostic certainty of ALS in accordance with the El Escorial Revisited criteria. The disease state was determined using the modified ALS health state scale of Riviere et al. (Arch Neurol 1998:55;526-8). Red-cell SOD1 activity was determined by spectrophotometry. SOD1 activity in red cells was compared statistically with diagnostic criteria and disease state. Red cell SOD1 activity was high in all SALS patients, but there was no significant association between enzyme activity and diagnostic criteria and disease state. In this preliminary study, we did not find any correlation between SOD1 activity level and diagnosis or prognosis. Measured SOD1 activity sometimes supports ALS diagnosis, but it is neither a specific nor a prognostic factor.

SOD1 gene mutations in Italian patients with Sporadic Amyotrophic Lateral Sclerosis (ALS)

Mutations in the SOD1 gene exons and exon/intron boundaries were searched in 66 sporadic and 4 familial Italian ALS cases consecutively referred to our centre from different Italian regions. A mutation was found in three sporadic cases (4.5%): a new nonsense mutation in exon 5 (K136X) in a patient with a rapid and severe disease course and two previously described missense nucleotide substitutions (N65S and A95T) in two patients with a mild disease course. Comparison of the clinical characteristics with previously reported patients carrying the same or similar mutations showed a remarkable genotype-phenotype correlation. No association was found with intronic sequence variations by comparing their frequency in the patients and in 181 matched controls.

Mitochondrial dysfunction and increased sensitivity to excitotoxicity in mice deficient in DNA mismatch repair

The expression profile in the hippocampus of mice lacking one allele of the MutS homologue (Msh2), gene, which is one of the most representative components of the DNA mismatch repair system, was analysed to understand whether defects in the repair or in response to DNA damage could impact significantly on brain function. The overall results suggested a reduction in mitochondrial function as indicated by gene expression analysis, biochemical and behavioural studies. In the hippocampus of Msh2+/- mice, array data, validated by RT-PCR and western blot analysis, showed reduced expression levels of genes for cytochrome c oxidase subunit 2 (CoxII), ATP synthase subunit beta and superoxide dismutase 1. Biochemically, mitochondria from the hippocampus and cortex of these mice show reduced CoxII and increased aconitase activity. Behaviourally, these alterations resulted in mice with increased vulnerability to kainic acid-induced epileptic seizures and hippocampal neuronal loss. These data suggest that lack of an efficient system involved in recognizing and repairing DNA damage may generate a brain mitochondriopathy.

No association of DYNC1H1 with sporadic ALS in a case-control study of a northern European derived population: a tagging SNP approach

The cytoplasmic dynein-dynactin complex has been implicated in the aetiology of motor neuron degeneration in both mouse models and human forms of motor neuron disease. We have previously shown that mutations in the cytoplasmic dynein 1 heavy chain 1 gene (Dync1h1) are causal in a mouse model of late-onset motor neuron degeneration but have found no association of the homologous sites in human DYNC1H1 with human motor neuron disease. Here we extend these analyses to investigate the DYNC1H1 genomic locus to determine if it is associated with sporadic amyotrophic lateral sclerosis (ALS) in a northern European-derived population. Among the 16 single nucleotide polymorphisms (SNPs) we examined, just two SNPs (rs2251644 and rs941793) were sufficient to tag the majority of haplotypic variation (r2 > or = 0.85) and these were tested in a case-control association study with 266 North American sporadic ALS patients and 225 matched controls. We found no association between genetic variation at DYNC1H1 and sporadic ALS (rs2251644; p = 0.538, rs941793; p = 0.204, haplotype; p = 0.956). In addition we investigated patterns of diversity at DYNC1H1 in Japanese and Cameroonian populations to establish the evolutionary history for this gene and observed reduced genetic diversity in the northern Europeans suggestive of selection at this locus.