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Peripheral neuropathy commonly occurs in both hereditary and acquired amyloidosis. Immunoglobulin light chain (AL) amyloidosis is the most common form of acquired amyloidosis, whereas transthyretin (TTR) amyloidosis is the most common form of hereditary amyloidosis. When neuropathy is the primary feature of amyloidosis related to a TTR mutation, it is often referred to as neuropathic hATTR amyloidosis. Here we present a case of neuropathic hATTR amyloidosis to illustrate the clinical and pathological features and to discuss exciting new therapies.

Over-expression of mutant copper, zinc superoxide dismutase (SOD) in mice induces ALS and has become the most widely used model of neurodegeneration. However, no pharmaceutical agent in twenty years has extended lifespan by more than a few weeks. The Copper-Chaperone-for-SOD (CCS) protein completes the maturation of SOD by inserting copper, but paradoxically human CCS causes mice co-expressing mutant SOD to die within two weeks of birth. Hypothesizing that co-expression of CCS created copper deficiency in spinal cord, we treated these pups with the PET-imaging agent CuATSM, which is known to deliver copper into the CNS within minutes. CuATSM prevented the early mortality of CCSxSOD mice, while markedly increasing Cu,Zn SOD protein in their ventral spinal cord. Remarkably, continued treatment with CuATSM extended the survival of these mice by an average of 18 months. When CuATSM treatment was stopped, these mice developed ALS-related symptoms and died within three months. Restoring CuATSM treatment could rescue these mice after they became symptomatic, providing a means to start and stop disease progression. All ALS patients also express human CCS, raising the hope that familial SOD ALS patients could respond to CuATSM treatment similarly to the CCSxSOD mice.

ObjectiveTo identify the rate of change of clinical outcome measures in children with 2 types of congenital muscular dystrophy (CMD), COL6-related dystrophies (COL6-RDs) and LAMA2-related dystrophies (LAMA2-RDs).MethodsOver the course of 4 years, 47 individuals (23 with COL6-RD and 24 with LAMA2-RD) 4 to 22 years of age were evaluated. Assessments included the Motor Function Measure 32 (MFM32), myometry (knee flexors and extensors, elbow flexors and extensors), goniometry (knee and elbow extension), pulmonary function tests, and quality-of-life measures. Separate linear mixed-effects models were fitted for each outcome measurement, with subject-specific random intercepts.ResultsTotal MFM32 scores for COL6-RDs and LAMA2-RDs decreased at a rate of 4.01 and 2.60 points, respectively, each year (p < 0.01). All muscle groups except elbow flexors for individuals with COL6-RDs decreased in strength between 1.70% (p < 0.05) and 2.55% (p < 0.01). Range-of-motion measurements decreased by 3.21° (p < 0.05) at the left elbow each year in individuals with LAMA2-RDs and 2.35° (p < 0.01) in right knee extension each year in individuals with COL6-RDs. Pulmonary function demonstrated a yearly decline in sitting forced vital capacity percent predicted of 3.03% (p < 0.01) in individuals with COL6-RDs. There was no significant change in quality-of-life measures analyzed.ConclusionResults of this study describe the rate of change of motor function as measured by the MFM32, muscle strength, range of motion, and pulmonary function in individuals with COL6-RDs and LAMA2-RDs.

A 26-year-old right-handed man presented with progressive gait imbalance over 6 years. His examination was consistent with cerebellar and upper motor neuronal dysfunction. He had no significant family history. Most of the serum and cerebrospinal fluid studies were unremarkable. Neuroimaging was remarkable for mild cerebellar and noticeable thoracic spinal cord atrophy. The initial differential diagnosis for the patient's presentation was broad, but because of certain clinical characteristics, it was later focused on hereditary ataxias. Detailed analysis of the clinical features in the history, neurologic examination, and neuroimaging studies led to the diagnosis.

(2004). Western ALS Study Group. Amyotrophic Lateral Sclerosis and Other Motor Neuron Disorders: Vol. 5, No. sup1, pp. 121-124.

1. Missense mutations in the gene encoding Cu,Zn superoxide dismutase (SOD1) are responsible for causing one form of familial amyotrophic lateral sclerosis (FALS) linked to chromosome 21q. 2. Mutant SOD1-induced disease is clearly related to a toxic gain of function for the abnormal enzyme, and recent work has begun to investigate the mechanisms underlying this toxicity. In addition to its well known and likely beneficial dismutase activity, wild type SOD1 also possesses the ability to participate in other enzymatic reactions that may be injurious to cells including peroxidation or nitration. 3. Many of the SOD1 mutations associated with FALS appear to increase the likelihood that the enzyme will perform either one of those potentially harmful functions resulting in increased hydroxyl radical formation or the addition of nitro groups to tyrosine residues within cellular proteins. 4. Because several in vitro experiments have suggested that the extent of SOD1s ability to perform peroxidase and nitration reactions is dependent on the degree of copper and or zinc binding within the enzyme, these metals have become a focus of interest for understanding the exact mechanisms underlying motor neuron dysfunction in FALS as

Objective: To ascertain the specificity of alternatively spliced mRNA variants of the astroglial glutamate transporter EAAT2 for ALS. Background: An important hypothesis for ALS pathogenesis is that motor neuron injury may result from chronically elevated glutamate levels in the CNS. Supporting this idea are reports of decreased glutamate transport in ALS. This in turn has recently been suggested to be due to the presence of aberrant mRNA splice variants for EAAT2 in ALS. Methods: Postmortem human brain tissue was obtained from different brain regions of patients with ALS, normal controls (NC), and patients with AD and Lewy body dementia (LB)—neurodegenerative diseases in which motor neurons are unaffected. Brain RNA was analyzed for EAAT2 isoforms using reverse transcription PCR and cDNA cloning/sequencing methods. Results: Splice variants lacking exons 7 or 9 were present in ALS brain, as previously reported, but were also present in brains from NC, AD, and LB patients. PCR product sequence analyses from non-ALS brain show variant splicing identical to that reported for ALS. Quantitative PCR analysis shows that these isoforms may be somewhat more abundant in ALS than AD, LB, and NC brains. Conclusions: EAAT2 mRNA splice variants are found in the brains of NC and AD patients, as in ALS. The authors cannot exclude the possibility that quantitative changes in variant EAAT2 isoforms might relate directly, or indirectly, to ALS pathology. However, the qualitative presence of these “abnormal” EAAT2 splice variants does not appear to be sufficient to explain motor neuron degeneration in ALS.

Missense mutations in the gene encoding copper zinc superoxide dismutase (SOD1) have been found to cause one form of familial amyotrophic lateral sclerosis (FALS). Although the exact mechanism of disease is unknown, abnormalities in the ability of mutant SOD1 to bind zinc or copper ions may be crucial in the pathogenesis of disease. Because members of the metallothionein (MT) family of zinc and copper binding proteins function as important cellular regulators of metal ion bioavailability in the central nervous system, we used in situ hybridization and immunohistochemistry to study the expression pattern of these molecules in a transgenic mouse model of familial ALS. In adult wild-type mouse spinal cord, expression of MT-I and MT-II is restricted to ependymal cells and a subset of astrocytes located in white matter tracts, while MT-III synthesis is limited to neurons within gray matter. Compared to wild-type littermates, transgenic mice carrying the G93A SOD1 mutation demonstrate markedly increased expression of MT-I and MT-II within astrocytes in both white and gray matter as weakness develops. MT-III synthesis in neurons is also greatly upregulated as G93A SOD1 animals age, with glial cell expression of MT-III evident by later stages of the disease. Changes in MT expression occur before the onset of motor deficits or significant motor neuron pathology in G93A SOD1 mice and remarkably extend beyond ventral horn populations of neurons and glia. These results are consistent with the hypothesis that metallothioneins may serve an early and important protective function in FALS.

Evidence garnered from both human autopsy studies and genetic animal models has suggested a potential role for astrocytes in the pathogenesis of amyotrophic lateral sclerosis (ALS). Currently, mutations in the gene encoding Cu/Zn superoxide dismutase (SOD1) represent the only known cause of motoneuron loss in the disease, producing 21q linked familial ALS (FALS). To determine whether astrocytic dysfunction has a primary role in familial ALS, we have generated multiple lines of transgenic mice expressing G86R mutant SOD1 restricted to astrocytes. In GFAP-m SOD1 mice, astrocytes exhibit significant hypertrophy and increased GFAP reactivity as the animals mature. However, GFAP-mutant SOD1 transgenic mice develop normally and do not experience spontaneous motor deficits with increasing age. Histological examination of spinal cord in aged GFAP-mSOD1 mice reveals normal motoneuron and microglial morphology. These results indicate that 21q linked FALS is not a primary disorder of astrocytes, and that expression of mutant SOD1 restricted to astrocytes is not sufficient to cause motoneuron degenerationin vivo. Expression of mutant SOD1 in other cell types, most likely neurons, is critical for the initiation of disease.

Axonal forms of autosomal dominant hereditary motor and sensory neuropathies (HMSNs) represent a heterogeneous group of disorders based on genetic linkage studies. We recently identified one large family with axonal HMSN exhibiting linkage to chromosome 3q, designated HMSN IIB, and report here the clinical and electrodiagnostic features. We clinically evaluated 10 individuals with HMSN IIB and performed detailed electrophysiologic studies in 5 of these patients. HMSN IIB is characterized clinically by the presence of distal symmetric motor weakness and prominent sensory loss affecting the lower extremities with preserved ankle reflexes. Symptomatic age at onset is in the second or early third decade of life. Six patients with HMSN IIB had distal trophic ulcerations in the feet, leading to eventual toe amputations in four cases. Electrodiagnostic studies confirmed a distal sensorimotor axonopathy involving the lower limbs with normal motor conduction velocities. Tibial H-reflexes were preserved in HMSN IIB, despite the uniform loss of sural nerve potentials. Overall, individuals with HMSN IIB demonstrated a consistent clinical and electrodiagnostic phenotype that had no overlap with genetically unaffected family members. The identification of specific clinical and electrodiagnostic features of HMSN IIB may prove useful in the diagnosis and differentiation between various subtypes of HMSN II.

Several hypotheses have been proposed for the mechanisms underlying mutant Cu,Zn Superoxide Dismutase‐related Amyotrophic Lateral Sclerosis. These include aggregation pathology, mitochondrial dysfunctions, oxidative stress, and glutamate‐mediated excitotoxicity. Mitochondrial disease may be a primary event in neurodegeneration, contributing to oxidative stress and apoptosis, or it may be caused by other cellular processes. Mitochondrial structural abnormalities have been detected in the skeletal muscle, lymphoblast and central nervous system of Amyotrophic Lateral Sclerosis patients. The cause or even the extent of mitochondrial defects in spinal cord and brain of patients with Cu,Zn Superoxide Dismutase mutations is difficult to determine because of rapid mitochondrial deterioration in autopsy samples. The focus of this review is how abnormalities in Cu,Zn Superoxide Dismutase redox states, folding and metallation contribute to mitochondrial deficiencies, investigating the differences in mitochondrial defects observed among transgenic mice expressing various Cu,Zn Superoxide Dismutase mutations.

The selective vulnerability of limb and bulbar motor neurons is a hallmark of degenerative human motor neuron diseases such as amyotrophic lateral sclerosis (ALS). Currently, there are no known molecular characteristics to distinguish between motor neuron pools which are highly susceptible to degeneration in ALS and those populations which are resistant. Using in situ hybridization on adult rat tissue, we demonstrated that ALS-resistant motor pools robustly express mRNA for the calcium binding protein parvalbumin, while no measurable parvalbumin expression is found in ALS-sensitive motor neuron populations. In contrast, mRNA expression for each of several other calcium binding proteins such as calbindin-D28K, calretinin and calmodulin appears similar in the various motor pools. Thus, parvalbumin represents a biochemical marker of ALS-resistant motor neurons, and may provide insight into the mechanisms of resistance of certain motor neurons to disease.

Studies on the pathogenesis of human motor neurone disease have suffered from the absence of models of motor neurone degeneration in adult animals. Normally in adult rodents, transection of motor neurone axons results in only a modest degree of neuronal death. We reasoned that axotomy-induced motor neurone death might be enhanced by modulating glutamatergic transmission. By axotomizing the facial nerve in adult rats and then administering MK-801 for the first week of a 4-week or 8-week post-lesion survival period, we induced a 67% motor neurone loss by 8 weeks as compared with a 19% loss in controls. A possible explanation for the increased motor neurone loss after MK-801 treatment is that transient blockade of NMDA receptors may upregulate synthesis of NMDA receptor components. In order to test this idea, we employed quantitativein situhybridization to determine the response of NMDAR1 mRNA to axotomy and axotomy + MK-801 treatment. Quantification of the percentage of area occupied by NMDAR1 silver grains per motor neurone somata indicated that axotomy alone did not provoke a change in NMDAR1 mRNA. However, axotomy and MK-801 combined treatment resulted in a highly significant upregulation of NMDAR1 mRNA when compared with controls or animals treated solely with axotomy. Our results suggest that motor neurone death in adult animals can be enhanced after axotomy in association with the upregulation of NMDA receptor mRNA. Thus, abnormalities in glutamate receptor signalling may lead to subacute motor neurone deathin vivo. Furthermore these results indicate that transient treatment with MK-801 is a convenient method for enhancing the degree of motor neurone death after axotomy in adult animals.

Background There have been a few case reports of motor neuron disease in association with Huntington disease (HD). Objective To describe a patient presenting with prominent fasciculations, chorea, and possible amyotrophic lateral sclerosis (ALS) in whom genetic testing revealed HD mutation. Design Case report. Setting University of Texas Southwestern Medical Center, Dallas. Patient A 69-year-old man with chorea and fasciculations. Interventions Genetic and electrophysiologic testing. Main Outcome Measures Genetic test result, electrophysiologic test result, and physical examination. Results A 69-year-old man with long-standing depression and failing memory presented with muscle twitches of 8 months' duration. He was found to have choreoathetoid movements and distal weakness on neurological examination. Electrophysiologic studies revealed evidence of motor neuron disease. Genetic test showed CAG repeat of 40 on chromosome 4, confirming the diagnosis of HD. Conclusion Motor neuron disease can rarely occur in patients with HD and could be one of its presenting features.

The primary biological function of the endogenous cellular prion protein has remained unclear. We investigated its biological function in the generation of cellular immune responses using cellular prion protein gene-specific small interfering ribonucleic acid in vivo and in vitro. Our results were confirmed by blocking cellular prion protein with monovalent antibodies and by using cellular prion protein-deficient and -transgenic mice. In vivo prion protein gene-small interfering ribonucleic acid treatment effects were of limited duration, restricted to secondary lymphoid organs and resulted in a 70% reduction of cellular prion protein expression in leukocytes. Disruption of cellular prion protein signalling augmented antigen-specific activation and proliferation, and enhanced T cell receptor signalling, resulting in zeta-chain-associated protein-70 phosphorylation and nuclear factor of activated T cells/activator protein 1 transcriptional activity. In vivo prion protein gene-small interfering ribonucleic acid treatment promoted T cell differentiation towards pro-inflammatory phenotypes and increased survival of antigen-specific T cells. Cellular prion protein silencing with small interfering ribonucleic acid also resulted in the worsening of actively induced and adoptively transferred experimental autoimmune encephalomyelitis. Finally, treatment of myelin basic protein(1-11) T cell receptor transgenic mice with prion protein gene-small interfering ribonucleic acid resulted in spontaneous experimental autoimmune encephalomyelitis. Thus, central nervous system autoimmune disease was modulated at all stages of disease: the generation of the T cell effector response, the elicitation of T effector function and the perpetuation of cellular immune responses. Our findings indicate that cellular prion protein regulates T cell receptor-mediated T cell activation, differentiation and survival. Defects in autoimmunity are restricted to the immune system and not the central nervous system. Our data identify cellular prion protein as a regulator of cellular immunological homoeostasis and suggest cellular prion protein as a novel potential target for therapeutic immunomodulation.

An Innervative Small RNA Amyotrophic lateral sclerosis (ALS) is a relentless disease characterized by progressive degeneration of motor neurons that control muscle movement, leading to muscle atrophy and paralysis. Williams et al. (p. 1549 ; see the Perspective by Brown ) show that a small noncoding RNA that is selectively expressed in skeletal muscle, miR-206, senses motor neuron injury or loss and helps ameliorate resultant muscle damage by promoting regeneration of neuromuscular synapses. Expression of miR-206 was dramatically induced in a mouse model of ALS, and when this RNA was removed from mice by genetic manipulation, the disease progressed at a faster rate. The salutary effects of miR-206 appear to be mediated through a signaling pathway in muscle cells involving histone deacetylase 4 and a fibro-blast growth factor modulator, activation of which leads to release of factors that promote nerve-muscle interactions.

Mutations in the Cu/Zn superoxide dismutase (SOD1) gene cause one form of familial amyotrophic lateral sclerosis, a progressive disorder of motor neurons leading to weakness and death of affected individuals. Experiments using both transgenic mice expressing mutant SOD1 and SOD1 knock-out mice have demonstrated that disease is caused by a toxic gain of function and not by a loss of normal SOD1 activity. Precise mechanisms underlying mutant SOD1 toxicity are unclear but may involve abnormal interactions between zinc and SOD1. The metallothioneins (MTs) represent a family of zinc binding proteins that can function as zinc chaperones for apo-SOD1 in vitro. We hypothesized that manipulation of metallothioneins in vivo might alter the disease phenotype of transgenic mice expressing G93A SOD1 and therefore crossed this line with MT-I and MT-II or MT-III knock-out mice. G93A SOD1 mice deficient of either MT-I and MT-II or MT-III exhibited significant reductions in survival compared with G93A SOD1 mice. In addition, motor dysfunction was markedly accelerated in G93A SOD1 mice deficient in metallothioneins with regard to onset (MT-I and MT-II) or progression (MT-III). These results indicate that the disease course in G93A SOD1 mice is dependent on levels of metallothionein expression. Because MT-I and MT-II are expressed in glia whereas MT-III is found in neurons, these results also indicate that primary changes within non-neuronal cells can affect mutant SOD1-induced disease and do so in ways distinct from primary neuronal changes.

Although pronounced changes in astrocytes and microglia accompany the neuronal degeneration observed in a murine model of familial amyotrophic lateral sclerosis, the significance of non-neuronal cell contribution to the disease process remains unclear. Activated astrocytes and microglia are capable of secreting numerous cytokines, some of which may have potentially harmful effects on neuron survival. For this reason we wished to determine the expression pattern of various cytokines in the spinal cords of transgenic mice expressing a Cu–Zn superoxide dismutase mutation (Tgn G93A SOD1) by using semi-quantitative RT–PCR. Three different patterns of cytokine expression were observed in G93A SOD1 transgenic mice. For most cytokines, we were unable to detect mRNA expression in Tgn G93A SOD1 mouse spinal cords at any age, yet message was readily detected in spleen or activated splenocytes. A second pattern, typified by TNF-α, was characterized by mRNA expression prior to the onset of motor deficits and increasing until the terminal stages of the disease. For other cytokines, including TGF-β1 and M-CSF, mRNA expression was detected in young presymptomatic Tgn G93A SOD1 mice (as well as wild-type and transgenic mice expressing wild-type SOD1 (Tgn SOD1)), with upregulation later occurring only in G93A SOD1 transgenic mice. These results indicate a temporal correlation between the expression of certain cytokines and the onset of motor dysfunction in Tgn G93A SOD1 mice and suggest a potential role for these molecules in the disease.

Amyotrophic lateral sclerosis (ALS) is a chronic neurodegenerative disease characterized by the progressive loss of motor neurons, leading to profound weakness and eventual death of affected individuals. For the vast majority of patients with ALS, the etiology of the disorder is unknown, and although multiple clinical trials of various therapeutic agents have been undertaken, truly effective therapy is not currently available for the disease. The selection of treatments used in ALS clinical trials frequently has its basis in promising data obtained from experimental model systems in which the proposed agent has shown some effect in protecting motor neurons from a particular insult. The likelihood of a successful clinical outcome for a given treatment in ALS would therefore depend on two principal factors, including the similarity of the model to the disease and the biologic action of the potential therapeutic agent. Partly because early experimental models of ALS failed to replicate the disease process, treatment success in these models did not carry over into human trials. Recently, however, a variety of newer model systems have been developed and utilized to investigate motor neuron degeneration as related to ALS. For example, in this issue, Corse et al. use a rat spinal cord organotypic slice subjected to glutamate excitotoxicity as a model system to test the effectiveness of neurotrophic factors in preventing motor neuron degeneration. This review will assess the strengths and weaknesses of differing ALS model systems that have been used to preclinically test potential drug efficacy in ALS.

Objective: To describe a sporadic motor neuron disorder that remains largely restricted to the upper limbs over time. Background: Progressive amyotrophy that is isolated to the upper limbs in an adult often suggests ALS. The fact that weakness can remain largely confined to the arms for long periods of time in individuals presenting with this phenotype has not been emphasized. Methods: We reviewed the records of patients who had a neurogenic “man-in-the-barrel” phenotype documented by examination at least 18 months after onset. These patients had severe bilateral upper-extremity neurogenic atrophy that spared lower-extremity, respiratory, and bulbar musculature. Results: Nine of 10 patients meeting these criteria had a purely lower motor neuron disorder. During follow-up periods ranging from 3 to 11 years from onset, only three patients developed lower-extremity weakness, and none developed respiratory or bulbar dysfunction or lost the ability to ambulate. Conclusion: Patients presenting with severe weakness that is fully isolated to the upper limbs, without pyramidal signs, may have a relatively stable variant of motor neuron disease.

The purpose of this study was to search for STA gene defects in three families with clinically typical Emery-Dreifuss muscular dystrophy. Emery-Dreifuss is an X-linked muscular dystrophy with humeroperoneal weakness and life-threatening, but treatable, cardiac abnormalities in male patients and in female carriers. The defect is in the gene coding for emerin, a 254 amino acid protein of unknown function. Complementary and genomic DNA from T lymphocytes from the reported patients and their family members were amplified, cloned, and sequenced. A novel mutation, a 26 base-pair deletion in three brothers and a carrier mother, was detected in one family. A splicing mutation with one base pair insertion and a five base-pair deletion, which have been described previously, were found in the second and third families, respectively. The additional novel mutation detected and the findings of three different mutations in these three families support the idea of genetic heterogeneity of Emery-Dreifuss muscular dystrophy with different mutations in different families.

Members of the BCL2-related family of proteins either promote or repress programmed cell death. BAX, a death-promoting member, heterodimerizes with multiple death-repressing molecules, suggesting that it could prove critical to cell death. We tested whether Bax is required for neuronal death by trophic factor deprivation and during development. Neonatal sympathetic neurons and facial motor neurons from Bax-deficient mice survived nerve growth factor deprivation and disconnection from their targets by axotomy, respectively. These salvaged neurons displayed remarkable soma atrophy and reduced elaboration of neurites; yet they responded to readdition of trophic factor with soma hypertrophy and enhanced neurite outgrowth. Bax-deficient superior cervical ganglia and facial nuclei possessed increased numbers of neurons. Our observations demonstrate that trophic factor deprivation–induced death of sympathetic and motor neurons depends on Bax.

The discovery that some cases of familial amyotrophic lateral sclerosis (FALS) are associated with mutations in the gene encoding Cu/Zn superoxide dismutase (SOD1) has focused much attention on the function of SOD1 as related to motor neuron survival. Here we describe the creation and characterization of mice completely deficient for this enzyme. These animals develop normally and show no overt motor deficits by 6 months in age. Histological examination of the spinal cord reveals no signs of pathology in animals 4 months in age. However Cu/Zn SOD-deficient mice exhibit marked vulnerability to motor neuron loss after axonal injury. These results indicate that Cu/Zn SOD is not necessary for normal motor neuron development and function but is required under physiologically stressful conditions following injury.

Motor neuropathies associated with electrodiagnostic evidence of motor conduction block often improve after treatment with immunotherapy, but there is less evidence about the responsiveness of lower motor neuron (LMN) syndromes without conduction block. In this study we treated four patients with an asymmetric, predominantly distal LMN syndrome associated with high serum titers of IgM anti-GM1 ganglioside antibodies but without conduction block on electrodiagnostic testing. Treatment courses consisted of five to seven repeated monthly regimens of plasma exchange on 2 consecutive days followed, on day 3, by intravenous cyclophosphamide (1 g/m2). The results of treatment were quantitatively measured using hand-held dynamometry. We found that all four patients showed progressive improvement in strength over the 6 to 24 months following treatment. Improvement was documented by both objective muscle testing and patient reports of increased strength and less fatigability. We conclude that immunotherapy may be followed by useful functional benefit in selected patients with an asymmetric, predominantly distal LMN syndrome associated with high serum titers of IgM anti-GM1 antibodies. Gradual improvement often begins as late as 6 to 9 months after the onset of treatment and may persist for 1 to 2 years, or longer, after immunosuppressive treatment is stopped.