Brain TDP-43 pathology in corticobasal degeneration: Topographical correlation with neuronal loss.

AIMS: Neuronal and glial inclusions comprising transactive response DNA-binding protein of 43 kDa (TDP-43) have been identified in the brains of patients with corticobasal degeneration (CBD), and a possible correlation between the presence of these inclusions and clinical phenotypes has been speculated. However, the significance of TDP-43 pathology in the pathomechanism of CBD has remained unclear. Here, we investigated the topographical relationship between TDP-43 inclusions and neuronal loss in CBD. METHODS: We estimated semi-quantitatively neuronal loss and TDP-43 pathology in the form of neuronal cytoplasmic inclusions (NCIs), astrocytic inclusions (AIs), oligodendroglial cytoplasmic inclusions (GCIs), and dystrophic neurites in 22 CNS regions in 10 patients with CBD. Then, the degree of correlation between the severity of neuronal loss and the quantity of each type of TDP-43 inclusion was assessed. We also investigated tau pathology in a similar manner. RESULTS: TDP-43 pathology was evident in nine patients. The putamen and globus pallidus were the regions most frequently affected (80%). NCIs were the most prominent form, and their quantity was significantly correlated with the severity of neuronal loss in more than half of the regions examined. The quantities of TDP-43 NCIs and tau NCIs were correlated in only a few regions. The number of regions where the quantities of TDP-43 AIs and GCIs were correlated with the severity of neuronal loss was apparently small in comparison with that of NCIs. CONCLUSIONS: TDP-43 alterations in neurons, not closely associated with tau pathology, may be involved in the pathomechanism underlying neuronal loss in CBD. There was a significant topographical correlation between neuronal cytoplasmic aggregation of TDP-43 and neuronal loss in CBD, suggesting that TDP-43 protein aberration might be associated with neuronal degeneration in CBD. There was no close correlation between the burden of TDP-43 and that of tau in neurons.

Genetic Variations and Neuropathologic Features of Patients with PRKN Mutations.

BACKGROUND: Mutations in PRKN are the most common cause of autosomal recessive juvenile parkinsonism. The objective of this study was to investigate the association between genotype and pathology in patients with PRKN mutations. METHODS: We performed a sequence and copy number variation analysis of PRKN, mRNA transcripts, Parkin protein expression, and neuropathology in 8 autopsied patients. RESULTS: All the patients harbored biallelic PRKN mutations. Two patients were homozygous and heterozygous, respectively, for the missense mutation p.C431F. Seven patients had exon rearrangements, including 2 patients from a single family who harbored a homozygous deletion of exon 4, and 3 patients who carried a homozygous duplication of exons 6-7, a homozygous duplication of exons 10-11, and a heterozygous duplication of exons 2-4. In the other 2 patients, we found a compound heterozygous duplication of exon 2, deletion of exon 3, and a heterozygous duplication of exon 2. However, sequencing of cDNA prepared from mRNA revealed 2 different transcripts derived from triplication of exon 2 and deletion of exons 2-3 and from duplication of exons 2-4 and deletion of exons 3-4. Western blotting and immunohistochemistry revealed faint or no expression of Parkin in their brains. In the substantia nigra pars compacta, a subfield-specific pattern of neuronal loss and mild gliosis were evident. Lewy bodies were found in 3 patients. Peripheral sensory neuronopathy was a feature. CONCLUSIONS: Genomic and mRNA analysis is needed to identify the PRKN mutations. Variable mutations may result in no or little production of mature Parkin and the histopathologic features may be similar. © 2021 International Parkinson and Movement Disorder Society.

Parkinson's disease and parkinsonism: Clinicopathological discrepancies on diagnosis in three patients.

Parkinson's disease (PD) is one of the most common neurodegenerative disorders. The cardinal neuropathological features of PD include selective and progressive loss of pigmented neurons in the substantia nigra, deficiencies in dopaminergic signaling in the striatum, and occurrence of phosphorylated α-synuclein-identified Lewy bodies in the nervous system. Parkinsonism, the clinical presentation of movement disorders seen in PD, is a feature shared commonly by other pathologically distinct neurodegenerative diseases, such as progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and multiple system atrophy (MSA). Consequently, it is sometimes difficult to distinguish PD from such parkinsonism-related neurological disorders. In addition, parkinsonism is not always a feature of certain neurodegenerative diseases, and it can sometimes develop as a result of various forms of drug intoxication or cerebrovascular disease. Here, we describe the clinicopathological features of three patients (cases 1, 2, and 3) diagnosed as having PSP, MSA, and PD, respectively, in each of whom the postmortem histopathological diagnosis differed from the final clinical diagnosis. Neuropathologically, they had suffered from coexistent disorders: PD, MSA, and argyrophilic grain disease (case 1); PD (case 2); and vascular parkinsonism (case 3). The variety of patients showing features of parkinsonism underlines the importance of careful long-term follow up followed by postmortem neuropathological evaluation.

Abnormal distribution of GABAA receptors in brain of duchenne muscular dystrophy patients.

INTRODUCTION: In this study we sought to: (1) determine the distribution of GABAA receptors (GABAA -Rs) in the brain of Duchenne muscular dystrophy (DMD) patients; and (2) ascertain if the distribution pattern correlates with cognitive dysfunction. METHODS: Fourteen DMD patients [young adult (n = 7, 18-25 years old) and older adult (n = 7, 30-37 years old) groups] and 16 age-matched normal volunteers participated. GABAA -R distribution was assessed using 123 I-IMZ-SPECT. Neuropsychological assessments were performed using 3 different test batteries, the WAIS-III, WMS-R, and Wisconsin Card Sorting Test (WCST). RESULTS: All DMD patients showed significant decline in 123 I-IMZ uptake in the prefrontal cortex (P < 0.05). Although no differences were detected in the WAIS-III and WMS-R, the WCST scores of DMD patients (2.8 ± 1.9) were significantly lower (P < 0.01) than those of normal volunteers (5.4 ± 0.7). Both abnormalities were more pronounced in older adult patients. CONCLUSION: The findings demonstrate that DMD is accompanied by a reduction in the prefrontal cortex distribution of GABAA -Rs. Muscle Nerve 55: 591-595, 2017.

Progressive myoclonus epilepsy: extraneuronal brown pigment deposition and system neurodegeneration in the brains of Japanese patients with novel SCARB2 mutations.

AIMS: Mutations in the SCARB2 gene cause a rare autosomal recessive disease, progressive myoclonus epilepsy (PME) with or without renal failure, the former also being designated action myoclonus-renal failure syndrome. Although reported cases have been accumulating, only a few have described its neuropathology. We studied two Japanese patients with PME without renal failure, in whom the ages at onset and disease durations were 45 and 20 years, and 14 and 8.5 years respectively. METHODS: Sequencing and restriction analysis of the SCARB2 gene and neuropathological examination with immunohistochemistry were performed. RESULTS: Gene analyses revealed novel homozygous frameshift and nonsense mutations in the SCARB2 gene. Both cases exhibited deposition of brown pigment in the brain, especially the cerebellar and cerebral cortices. Ultrastructurally, the pigment granules were localized in astrocytes. Neuronal loss and gliosis were also evident in the brain, including the pallidoluysian and cerebello-olivary systems. The spinal cord was also affected. Such changes were less severe in one patient with late-onset disease than in the other patient with early-onset disease. In brain and kidney sections, immunostaining with an antibody against the C-terminus of human SCARB2 revealed decreased levels and no expression of the protein respectively. CONCLUSIONS: The frameshift mutation detected in the patient with late-onset disease is a hitherto undescribed, unique type of SCARB2 gene mutation. The present two patients are the first reported to have clearly demonstrated both extraneuronal brown pigment deposition and system neurodegeneration as neuropathological features of PME with SCARB2 mutations.

Pathology and sensitivity of current clinical criteria in corticobasal syndrome.

The aim of this study was to investigate corticobasal syndrome with respect to underlying pathologies, the ability of current clinical criteria to detect early stages of disease, and symptoms and signs predicting background pathologies. We retrospectively analyzed the clinicopathological findings from patients with corticobasal syndrome. We also analyzed whether those findings fulfilled the diagnostic criteria for corticobasal degeneration (CBD). Finally, we investigated characteristic clinical features that are specific to each background pathology. Of 10 consecutive autopsied patients who had corticobasal syndrome (mean age ± standard deviation, 67.9 ± 9.3 years; male:female ratio, 6:4), three had corticobasal degeneration pathology, three had progressive supranuclear palsy, three had Alzheimer's disease, and one had atypical four-repeat tauopathy. Nine patients fulfilled Mayo criteria, and all 10 patients fulfilled modified Cambridge criteria at the later stage, but only two patients fulfilled either clinical criteria within 2 years of disease onset. Five patients fulfilled the clinical criteria for possible CBD (p-CBD), and one patient fulfilled the clinical research criteria for probable sporadic CBD (cr-CBD) at the later stage. Only two patients fulfilled the criteria for either p-CBD or cr-CBD within 2 years of disease onset. Although we could not find any predictive characteristic clinical features that were specific to CBD pathology, only patients with progressive supranuclear palsy developed apraxia of eyelid opening and cerebellar ataxia. Myoclonus and memory impairment, especially if they appear at an early stage of the disease, may predict Alzheimer's disease pathology. Sensitivity of the available clinical criteria for corticobasal syndrome was poor within 2 years of disease onset.

Autosomal Recessive Spinocerebellar Ataxia Type 10: A Report of a New Case in Japan.

Autosomal recessive spinocerebellar ataxia of type 10 (SCAR10) is a very rare neurodegenerative disease caused by mutations in the TMEM16K (ANO10) gene. This disorder is characterized by slowly progressive cerebellar ataxia and pyramidal signs inconstantly associated with cognitive decline, polyneuropathy, epilepsy, and vesicorectal dysfunction. To date, more than 40 cases have been reported in Europe. In contrast, only three cases have been identified in Asian countries. We herein report the third Japanese case of SCAR10 harboring a novel homozygous deletion mutation (c.616delG, p.Glu206Lysfs*17). This case presented with adult-onset slowly progressive spastic ataxia with cerebellar atrophy and mild cognitive decline.

Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay without Spasticity.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a rare progressive neurodegenerative disease caused by either homozygous or compound heterozygous mutations in the SACS gene. The original ARSACS cases found in Quebec showed very homogenous phenotypes characterized by cerebellar ataxia, spasticity, and polyneuropathy. However, many cases with atypical phenotypes have been found in other regions and ethnic groups. We herein present a Japanese patient with atypical ARSACS who showed cerebellar ataxia and polyneuropathy, but no spasticity. She carried novel compound heterozygous mutations (p.Lys4326Glu and p.Leu1412Lysfs*16) in the SACS gene. The brain MRI findings were useful for making a diagnosis of ARSACS.

Dementia and delirium in 4 patients with Machado-Joseph disease.

BACKGROUND: Machado-Joseph disease (MJD; spinocerebellar ataxia type 3) is a hereditary neurodegenerative disease caused by mutation of the MJD1 gene. Patients with MJD usually present with cerebellar ataxia, external ophthalmoplegia, pyramidal and extrapyramidal signs, and muscle wasting. However, it has been reported that these patients do not demonstrate dementia. CASE DESCRIPTION: We noticed symptoms of dementia and delirium in 4 patients with MJD. The symptoms included abnormal behavior, excitation, an uncooperative attitude, crying, disorientation, slow thought processes, hallucinations, and delusions. These symptoms were observed in patients with a relatively young onset age, and after a long clinical course. In these patients, the CAG repeat length in the MJD1 gene was much longer compared with the mean repeat length found in patients with MJD. On electroencephalographical examination, they showed slow background activity, but computed tomography and magnetic resonance imaging scans showed no cerebrocortical atrophy. Neuropathological findings in 2 patients revealed a normal cortical structure on conventional morphological examination, but at immunohistochemical examination, we found abnormal staining by an antipolyglutamine antibody in the cerebrocortical neuronal nuclei. CONCLUSIONS: Symptoms of dementia and delirium in patients with MJD could occur in the late stages, and they might be caused not by loss of cerebrocortical neurons, but by their dysfunction.

Prognostic impact of left ventricular noncompaction in patients with Duchenne/Becker muscular dystrophy--prospective multicenter cohort study.

BACKGROUND: The reported prevalence of left ventricular noncompaction (LVNC) varies widely and its prognostic impact remains controversial. We sought to clarify the prevalence and prognostic impact of LVNC in patients with Duchenne/Becker muscular dystrophy (DMD/BMD). METHODS: We evaluated the presence of LNVC in patients with DMD/BMD aged 4-64 years old at the study entry (from July 2007 to December 2008) and prospectively followed-up their subsequent courses (n=186). The study endpoint was all-cause death and the presence of LVNC was blinded until the end of the study (median follow-up: 46 months; interquartile range: 41-48 months). RESULTS: There were no significant differences in baseline characteristics between patients with LVNC (n=35) and control patients without LVNC (n=151), with the exception of LV function. Patients with LVNC showed, in comparison with patients without LVNC, a significant negative correlation between age and LVEF (R=-0.7 vs. R=-0.4) at baseline; and showed a significantly greater decrease in absolute LVEF (-8.6 ± 4.6 vs. -4.3 ± 4.5, p<0.001) during the follow-up. A worse prognosis was observed in patients with LVNC (13/35 died) than in patients without LVNC (22/151 died, Log-rank p<0.001). Multivariate Cox analysis revealed that LVNC is an independent prognostic factor (relative hazard 2.67 [95% CI: 1.19-5.96]). CONCLUSION: LVNC was prevalent in patients with DMD/BMD. The presence of LVNC is significantly associated with a rapid deterioration in LV function and higher mortality. Neurologists and cardiologists should pay more careful attention to the presence of LVNC.

Cerebellar cortical tau pathology in progressive supranuclear palsy and corticobasal degeneration.

Immunohistochemical localization of tau in the cerebellar cortex was carried out using a mouse monoclonal antibody against phosphorylation-dependent tau (AT8) in brain tissue (cerebellum) from 13 patients with progressive supranuclear palsy (PSP), 7 patients with corticobasal degeneration (CBD) and 5 age-matched control subjects. Purkinje cell somata that showed diffuse granular accumulation of cytoplasmic tau were found occasionally in 9 of the 13 patients with PSP (69%) and in 4 of the 7 patients with CBD (57%). Tau-positive doughnut-shaped structures were also found occasionally in the cerebellar molecular layer in 6 of the 13 patients with PSP (46%) and 2 of the 7 patients with CBD (29%). No tau immunoreactivity was detected in the cerebellar cortex in the control tissue. In the tissue from one patient with PSP, we also performed a double-labeling immunofluorescence study with anti-glial fibrillary acidic protein (GFAP) antibody and AT8, as well as an immuno-electron microscopic study with AT8. In tau-positive Purkinje cell somata and dendrites, the reaction product was localized mainly within the rough endoplasmic reticulum and free ribosomes. Tau-positive doughnut-shaped structures were located in the GFAP-positive radial processes of Bergmann's glia and were present in the outer areas of inclusions reminiscent of Lewy bodies, which consist of aggregated pathological tau filaments. In conclusion, we have demonstrated a novel tau pathology that affects Purkinje cells and Bergmann's glia in patients with PSP and CBD, indicating that the cerebellar cortex can be involved in the disease processes in PSP and CBD.