A Japanese familial ALS patient with autonomic failure and a p.Cys146Arg mutation in the gene for SOD1 (SOD1)

Multifaceted superoxide dismutase 1 expression in amyotrophic lateral sclerosis patients: a rare occurrence?

Amyotrophic lateral sclerosis (ALS) is a neuromuscular condition resulting from the progressive degeneration of motor neurons in the cortex, brainstem, and spinal cord. While the typical clinical phenotype of ALS involves both upper and lower motor neurons, human and animal studies over the years have highlighted the potential spread to other motor and non-motor regions, expanding the phenotype of ALS. Although superoxide dismutase 1 (SOD1) mutations represent a minority of ALS cases, the SOD1 gene remains a milestone in ALS research as it represents the first genetic target for personalized therapies. Despite numerous single case reports or case series exhibiting extramotor symptoms in patients with ALS mutations in SOD1 (SOD1-ALS), no studies have comprehensively explored the full spectrum of extramotor neurological manifestations in this subpopulation. In this narrative review, we analyze and discuss the available literature on extrapyramidal and non-motor features during SOD1-ALS. The multifaceted expression of SOD1 could deepen our understanding of the pathogenic mechanisms, pointing towards a multidisciplinary approach for affected patients in light of new therapeutic strategies for SOD1-ALS.

Updated Genetic Analysis of Japanese Familial ALS Patients Carrying SOD1 Variants Revealed Phenotypic Differences for Common Variants

Background and Objectives

Amyotrophic lateral sclerosis (ALS) is an adult-onset progressive neurodegenerative disease. Approximately 10% of ALS cases are familial, and more than 20 causative genes have been identified. As we have previously reported, SOD1 variants are the most common causes of familial ALS in Japan. Because antisense oligonucleotides for SOD1-linked ALS are being used in practical applications, the types of variants and the clinical features of patients need to be updated.

Methods

We consecutively recruited 160 families with familial ALS in Japan. We performed genetic analyses, focusing on SOD1-linked ALS as the most common in our cohort, updated their genotypes, and characterized clinical phenotypes.

Results

A total of 26 SOD1 variants in 56 patients and 49 families (30.6%) were collected, with the 3 most common (p.His47Arg [the conventional numbering; H46R], p.Leu127Ser [L126S], p.Asn87Ser [N86S]) accounting for 38.8% of all families. We also identified 2 novel variants (p.Ile36Phe [I35F] and p.Asn132Argfs*3 [N131Rfs*3]). The mean age at onset was 48.9 ± 12.2 (mean ± SD) years for all patients with SOD1-linked ALS. Lower limb onset comprised 70% of cases. The mean disease duration was 64.7 ± 82 months, and the median survival was 71.5 months. Some variants led to a relatively homogeneous phenotype, although clinical characteristics differed among types of variants and families. Patients with p.His47Arg (H46R) showed slower progression with lower limb onset and a predominance of lower motor neuron involvement. The p.Leu127Ser (L126S) variant led to varying degrees of progression in heterozygous or homozygous states and presented incomplete penetrance. Intrafamilial phenotypic differences were observed in families carrying p.Asn87Ser (N86S). Four variants (p.Cys7Gly [C6G], p.His44Arg [H43R], p.Leu85Val [L84V], and p.Cys147Arg [C146R]) were found to be associated with rapid disease progression.

Discussion

The genetic basis of familial ALS, at least for SOD1 variants, still differed by geographic and ethnic background. Understanding these clinical profiles will help optimize evaluation in targeted gene therapy worldwide and benefit efficient diagnosis, leading to precise application in clinical practice.

Somatosensory pathway dysfunction in patients with amyotrophic lateral sclerosis in a completely locked-in state

OBJECTIVE

To investigate somatosensory pathway function in patients with amyotrophic lateral sclerosis (ALS) dependent on invasive ventilation and in a completely locked-in state (CLIS).

METHODS

We examined median nerve somatosensory evoked potentials (SEPs) in 17 ALS patients in a CLIS, including 11 patients with sporadic ALS, one with familial ALS with genes not examined, four with a Cu/Zn superoxide-dismutase-1 (SOD1) gene variant (Val118Leu, Gly93Ser, Cys146Arg), and one with a fused-in-sarcoma gene variant (P525L). We evaluated N9, N13, N20 and P25, and central conduction time (CCT); the data were compared with those of 73 healthy controls.

RESULTS

N20 and N13 were abolished in 12 and 10 patients, and their latencies was prolonged in four and three patients, respectively. The CCT was prolonged in five patients with measurable N13 and N20. Two patients with SOD1 gene mutations had absent or slightly visible N9. Compared to the CCT and latencies and amplitudes of N13 and N20 in the controls, those in the patient cohort were significantly abnormal.

CONCLUSIONS

The central somatosensory pathway is severely involved in patients with ALS in a CLIS.

SIGNIFICANCE

Our findings suggest that median nerve SEP cannot be utilized for communication in patients with ALS in a CLIS.

Autonome Diagnostik bei der Amyotrophen Lateralsklerose

Bei der Amyotrophen Lateralsklerose (ALS) handelt sich um eine neurodegenerative Multisystemerkrankung. Diese äußert sich neben den motorischen Defiziten mit nicht-motorischen Symptomen. Hierzu zählen auch autonome Störungen, die von veränderter Schweißsekretion über Tachykardie bis zu gastrointestinalen Symptomen reichen. Autonome Störungen können mit verschiedenen Methoden, wie Selbsterhebungsfragebögen, Messung der Herzfrequenzvariabilität, QTc-Intervallmessung, Erhebung der sudomotorischen Funktion und Sonographie des Nervus vagus erfasst werden, die in diesem Artikel dargestellt werden. Die bislang bei der ALS eingesetzten Methoden der autonomen Diagnostik ergeben zum Teil deutlich divergierende Ergebnisse über die Aktivität des Sympathikus im Krankheitsverlauf. Relevante autonome Störungen scheinen zumeist erst im fortgeschrittenen Krankheitsstadium aufzutreten, wobei multizentrische Studien mit longitudinalem Ansatz ausstehen.

Sensory Involvement in Amyotrophic Lateral Sclerosis

Although amyotrophic lateral sclerosis (ALS) is pre-eminently a motor disease, the existence of non-motor manifestations, including sensory involvement, has been described in the last few years. Although from a clinical perspective, sensory symptoms are overshadowed by their motor manifestations, this does not mean that their pathological significance is not relevant. In this review, we have made an extensive description of the involvement of sensory and autonomic systems described to date in ALS, from clinical, neurophysiological, neuroimaging, neuropathological, functional, and molecular perspectives.

Early presentation of lower urinary tract and bowel dysfunction in sporadic amyotrophic lateral sclerosis: A case report

An autopsy case of sporadic amyotrophic lateral sclerosis (ALS) with lower urinary tract (LUT) and bowel dysfunction is reported. The dysfunction occurred simultaneously with motor neuron symptoms in the early stages of the illness. A 75-year-old man developed exertional dyspnea and constipation following weight loss. Subsequently, he developed swallowing disturbance, fecal incontinence, and urinary retention. Neurological examination showed dysphagia, muscle weakness of the upper limbs, and prominent fasciculation affecting all four limbs and the tongue. All deep tendon reflexes were diminished, but the left plantar response was extensor. Orthostatic hypotension (OH) and the anal reflex were absent. Neuropathological findings did not show neuronal loss and gliosis in the thoracic and sacral intermediolateral nucleus (IML) and in Onuf's nucleus, whereas gliosis was observed in the periaqueductal gray (PAG) and striatum. Therefore, urinary retention may have resulted from involvement of the PAG. Phosphorylated TAR DNA binding protein 43 kDa (p-TDP-43)-positive inclusions were present in the peripheral nerves within the thoracic sympathetic ganglia, as well as the IML of the thoracic spinal cord. However, considering the lack of OH, the IML and peripheral sympathetic nerves unlikely played major roles. Furthermore, neuronal loss or p-TDP-43-immunoreactive deposits were absent in the Auerbach and Meissner plexuses of the rectum, suggesting that the responsible anatomical sites for fecal incontinence could not be found. Although it is difficult to elucidate the precise neuropathological lesions corresponding to LUT and bowel dysfunction, physicians need to recognize that neurogenic bladder and bowel dysfunction can occur in patients with ALS.

The importance of heart rate variability in predicting cardiac autonomic dysfunction in patients with amyotrophic lateral sclerosis

AIM

Amyotrophic lateral sclerosis (ALS) is a progressive disease characterized by degeneration in the upper and lower motor neurons of the corticospinal tract, brain stem, and spinal cord. Recent studies have revealed that the disease does not present solely with motor neuron involvement. Accordingly, the aim of this study is to investigate the presence of cardiac autonomic impairment in patients diagnosed with ALS.

MATERIAL AND METHOD

A total of 61 patients, who were diagnosed with ALS according to the Revised El Escorial Criteria (R-EEC), were included in this prospective study, in addition to the 29 healthy individuals, who were included in the study as controls. In order to assess the cardiac autonomic involvement, the presence of orthostatic hypotension was investigated, and transthoracic echocardiography and 24-hour electrocardiogram (ECG) using a Holter monitor were performed.

RESULTS

Orthostatic hypotension was detected in 14 (22.2%) patients. Holter electrocardiogram results of the patient group revealed statistically significantly lower heart rate variability (HRV) indicators in the time domain (SDNN, SDANN, SDNN index, rMSSD, and pNN50) and in the frequency domain (high frequency [HF], low frequency [LF], and very low frequency [VLF]) than those of the control group (P < .05).

CONCLUSION

Contrary to the popular opinion, cardiac autonomic dysfunction in patients with ALS can occur at any stage of the disease. Therefore, it is recommended that the patients are evaluated via periodic examinations during the follow-up period for cardiac autonomic involvement.

Pathophysiology and Treatment of Non-motor Dysfunction in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis is a progressive and fatal neurodegenerative disease typically presenting with bulbar or limb weakness. There is increasing evidence that amyotrophic lateral sclerosis is a multisystem disease with early and frequent impacts on cognition, behaviour, sleep, pain and fatigue. Dysfunction of normal physiological and metabolic processes also appears common. Evidence from pre-symptomatic studies and large epidemiological cohorts examining risk factors for the future development of amyotrophic lateral sclerosis have reported a high prevalence of changes in behaviour and mental health before the emergence of motor weakness. This suggests that changes beyond the motor system are underway at an early stage with dysfunction across brain networks regulating a variety of cognitive, behavioural and other homeostatic processes. The full impact of non-motor dysfunction continues to be established but there is now sufficient evidence that the presence of non-motor symptoms impacts overall survival in amyotrophic lateral sclerosis, and with up to 80% reporting non-motor symptoms, there is an urgent need to develop more robust therapeutic approaches. This review provides a contemporary overview of the pathobiology of non-motor dysfunction, offering readers a practical approach with regard to assessment and management. We review the current evidence for pharmacological and non-pharmacological treatment of non-motor dysfunction in amyotrophic lateral sclerosis and highlight the need to further integrate non-motor dysfunction as an important outcome measure for future clinical trial design.

Increased Axon Initial Segment Length Results in Increased Na+ Currents in Spinal Motoneurones at Symptom Onset in the G127X SOD1 Mouse Model of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease preferentially affecting motoneurones. Transgenic mouse models have been used to investigate the role of abnormal motoneurone excitability in this disease. Whilst an increased excitability has repeatedly been demonstrated in vitro in neonatal and embryonic preparations from SOD1 mouse models, the results from the only studies to record in vivo from spinal motoneurones in adult SOD1 models have produced conflicting findings. Deficits in repetitive firing have been reported in G93A SOD1^{(high copy number)} mice but not in presymptomatic G127X SOD1 mice despite shorter motoneurone axon initial segments (AISs) in these mice. These discrepancies may be due to the earlier disease onset and prolonged disease progression in G93A SOD1 mice with recordings potentially performed at a later sub-clinical stage of the disease in this mouse. To test this, and to explore how the evolution of excitability changes with symptom onset we performed in vivo intracellular recording and AIS labelling in G127X SOD1 mice immediately after symptom onset. No reductions in repetitive firing were observed showing that this is not a common feature across all ALS models. Immunohistochemistry for the Na⁺ channel Nav1.6 showed that motoneurone AISs increase in length in G127X SOD1 mice at symptom onset. Consistent with this, the rate of rise of AIS components of antidromic action potentials were significantly faster confirming that this increase in length represents an increase in AIS Na⁺ channels occurring at symptom onset in this model.

Clinical and Molecular Landscape of ALS Patients with SOD1 Mutations: Novel Pathogenic Variants and Novel Phenotypes. A Single ALS Center Study

Mutations in the copper zinc superoxide dismutase 1 (SOD1) gene are the second most frequent cause of familial amyotrophic lateral sclerosis (ALS). Nearly 200 mutations of this gene have been described so far. We report all SOD1 pathogenic variants identified in patients followed in the single ALS center of Lyon, France, between 2010 and 2020. Twelve patients from 11 unrelated families are described, including two families with the not yet described H81Y and D126N mutations. Splice site mutations were detected in two families. We discuss implications concerning genetic screening of SOD1 gene in familial and sporadic ALS.

A clinicopathological study of ALS with L126S mutation in the SOD1 gene presenting with isolated inferior olivary hypertrophy

We report an autopsy case of amyotrophic lateral sclerosis with L126S mutation in the superoxide dismutase 1 (SOD1) gene (SOD1). The patient was a 69-year-old Japanese man without relevant family history, who initially presented with slow progressive muscle weakness of the lower extremities without upper motor neuron signs, and died of respiratory failure 6 years after the onset. Neuropathological examination revealed a loss of lower motor neurons and degeneration of Clarke's column commensurate with that of the posterior spinocerebellar tract and the middle root zone of the posterior column. The primary motor area was minimally affected. Characteristic SOD1-immunopositive neuronal intracytoplasmic inclusions, mixed with neurofilament accumulation, were present in the affected areas. Isolated inferior olivary hypertrophy was observed, but did not involve the contralateral dentate nucleus, or the ipsilateral red nucleus and central tegmental tract, where no neuronal inclusions were found. In combination with data from a previous autopsy case, this study suggests that the L126S mutation may cause focal neuronal degeneration in the brainstem.

Identification and functional analysis of novel mutations in the SOD1 gene in Chinese patients with amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by selective involvement of motor neurons in the central nervous system (CNS). The most common causative gene of ALS in the Chinese population is the Cu/Zn superoxide dismutase 1 (SOD1) gene, which accounts for 20-42.9% of familial ALS (FALS) and 1-2% of sporadic ALS (SALS) cases. In this study, we identify three novel SOD1 mutations, Gly17Cys, Pro75Ser, and His121Gln, in four ALS pedigrees. A functional analysis was performed, and the results showed that all three mutations could lead to the formation of misfolded proteins. In addition, genotype-phenotype correlations in these patients are also described. Our study helps to characterize the genotype and phenotype of ALS with SOD1 mutations.

Non-motor manifestations in ALS patients with tracheostomy and invasive ventilation

INTRODUCTION

This study aimed to investigate non-motor manifestations in amyotrophic lateral sclerosis (ALS) patients with tracheostomy and invasive ventilation (TIV) and their relevance to disease progression.

METHODS

Sixty-seven ALS patients with TIV were enrolled, and followed-up prospectively. The patients were classified at the final evaluation into two subgroups according to the duration of TIV use or disease stage measured by communication impairment. We identified non-motor manifestations and investigated their frequencies and differences across the stages.

RESULTS

The non-motor manifestations were macroglossia (22.4%), unstable blood pressure (38.8%), hypothermia (26.9%), dysuria (50.7%), and hyperglycemia (12.1%). These manifestations occurred significantly more frequently in patients with TIV ≥5 years than in patients with TIV <5 years, and more in patients with severe communication impairment than in those with preserved communication ability.

DISCUSSION

Non-motor manifestations are observed at a high rate in ALS patients with TIV, and are possibly related to disease progression. Muscle Nerve 57: 735-741, 2018.

Clinicopathological characteristics of patients with amyotrophic lateral sclerosis resulting in a totally locked-in state (communication Stage V)

In the present study, we performed a comprehensive analysis to clarify the clinicopathological characteristics of patients with amyotrophic lateral sclerosis (ALS) that had progressed to result in a totally locked-in state (communication Stage V), in which all voluntary movements are lost and communication is impossible. In 11 patients, six had phosphorylated TAR DNA-binding protein 43 (pTDP-43)-immunoreactive (ir) neuronal cytoplasmic inclusions (NCI), two had fused in sarcoma (FUS)-ir NCI, and three had copper/zinc superoxide dismutase (SOD1)-ir NCI. The time from ALS onset to the need for tracheostomy invasive ventilation was less than 24 months in ten patients. Regardless of accumulated protein, all the patients showed common lesions in the pallido–nigro–luysian system, brainstem reticular formation, and cerebellar efferent system, in addition to motor neurons. In patients with pTDP-43-ir NCI, patients with NCI in the hippocampal dentate granule neurons (DG) showed a neuronal loss in the cerebral cortex, and patients without NCI in DG showed a preserved cerebral cortex. By contrast, in patients with FUS-ir NCI, patients with NCI in DG showed a preserved cerebral cortex and patients without NCI in DG showed marked cerebral degeneration. The cerebral cortex of patients with SOD1-ir NCI was preserved. Together, these findings suggest that lesions of the cerebrum are probably not necessary for progression to Stage V. In conclusion, patients with ALS that had progressed to result in communication Stage V showed rapidly-progressed symptoms, and their common lesions could cause the manifestations of communication Stage V.

Familial amyotrophic lateral sclerosis with an I104F mutation in the SOD1 gene: Multisystem degeneration with neurofilamentous aggregates and SOD1 inclusions

We previously reported familial amyotrophic lateral sclerosis (FALS) of 11 years duration in a 57-year-old woman, who received artificial ventilation for 5 years prior to death and exhibited widespread multisystem degeneration and neurofilamentous aggregates, so-called conglomerate inclusions (CIs). In the present study, we re-evaluated this autopsied patient (proband) with further immunohistochemical observation as well as mutational analysis of the superoxide dismutase 1 (SOD1) gene. A review of the clinical features of the proband's family revealed five affected members (including the proband) over two successive generations who showed marked variability in clinical presentation, such as the age at onset. The proband was found to harbor a heterozygous missense mutation in exon 4 (I104F) of the SOD1 gene. In the brain and spinal cord, SOD1-positive neuronal cytoplasmic inclusions (NCIs) were found to be more widely distributed than CIs, the latter being weakly positive for SOD1. No Lewy body-like hyaline inclusions were found. This is considered to be the first description of an autopsy case of FALS with an I104F SOD1 gene mutation, suggesting that combination of marked intra-familial clinical variability and multisystem degeneration with occurrence of CIs and SOD1-positive NCIs is a characteristic feature of FALS with this SOD1 gene mutation.