Decreased number of Gemini of coiled bodies and U12 snRNA level in amyotrophic lateral sclerosis.

Disappearance of TAR-DNA-binding protein 43 kDa (TDP-43) from the nucleus contributes to the pathogenesis of amyotrophic lateral sclerosis (ALS), but the nuclear function of TDP-43 is not yet fully understood. TDP-43 associates with nuclear bodies including Gemini of coiled bodies (GEMs). GEMs contribute to the biogenesis of uridine-rich small nuclear RNA (U snRNA), a component of splicing machinery. The number of GEMs and a subset of U snRNAs decrease in spinal muscular atrophy, a lower motor neuron disease, suggesting that alteration of U snRNAs may also underlie the molecular pathogenesis of ALS. Here, we investigated the number of GEMs and U11/12-type small nuclear ribonucleoproteins (snRNP) by immunohistochemistry and the level of U snRNAs using real-time quantitative RT-PCR in ALS tissues. GEMs decreased in both TDP-43-depleted HeLa cells and spinal motor neurons in ALS patients. Levels of several U snRNAs decreased in TDP-43-depleted SH-SY5Y and U87-MG cells. The level of U12 snRNA was decreased in tissues affected by ALS (spinal cord, motor cortex and thalamus) but not in tissues unaffected by ALS (cerebellum, kidney and muscle). Immunohistochemical analysis revealed the decrease in U11/12-type snRNP in spinal motor neurons of ALS patients. These findings suggest that loss of TDP-43 function decreases the number of GEMs, which is followed by a disturbance of pre-mRNA splicing by the U11/U12 spliceosome in tissues affected by ALS.

Primary lateral sclerosis: upper-motor-predominant amyotrophic lateral sclerosis with frontotemporal lobar degeneration--immunohistochemical and biochemical analyses of TDP-43.

Primary lateral sclerosis (PLS) is clinically defined as a disorder selectively affecting the upper motor neuron (UMN) system. However, recently it has also been considered that PLS is heterogeneous in its clinical presentation. To elucidate the association of PLS, or disorders mimicking PLS, with 43-kDa TAR DNA-binding protein (TDP-43) abnormality, we examined two adult patients with motor neuron disease, which clinically was limited almost entirely to the UMN system, and was followed by progressive frontotemporal atrophy. In the present study, the distribution and severity, and biochemical profile of phosphorylated TDP-43 (pTDP-43) in the brains and spinal cords were examined immunohistochemically and biochemically. Pathologically, in both cases, frontotemporal lobar degeneration with ubiquitin inclusions (FTLD-U) was evident, with the most severe degeneration in the motor cortex. An important feature in both cases was the presence of Bunina bodies and/or ubiquitin inclusions, albeit very rarely, in the well preserved lower motor neurons. The amygdala and neostriatum were also affected. pTDP-43 immunohistochemistry revealed the presence of many positively stained neuronal cytoplamic inclusions (NCIs) and dystrophic neurites/neuropil threads in the affected frontotemporal cortex and subcortical gray matter. By contrast, such pTDP-43 lesions, including NCIs, were observed in only a few lower motor neurons. pTDP-43 immunoblotting revealed that fragments of ∼25-kDa were present in the cortices, but not in the spinal cord in both cases. Genetically, neither of the patients had any mutation in the TDP-43 gene. In conclusion, we consider that although PLS may be a clinically significant disease entity, at autopsy, the majority of such clinical cases would present as upper-motor-predominant amyotrophic lateral sclerosis with FTLD-TDP.

Sporadic four-repeat tauopathy with frontotemporal lobar degeneration, Parkinsonism, and motor neuron disease: a distinct clinicopathological and biochemical disease entity.

Tau is the pathological protein in several neurodegenerative disorders classified as frontotemporal lobar degeneration (FTLD), including corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). We report an unusual tauopathy in three Japanese patients presenting with Parkinsonism and motor neuron disease (neuroimaging revealed frontotemporal cerebral atrophy in two patients who were examined). At autopsy, all cases showed FTLD with the most severe neuronal loss and gliosis evident in the premotor and precentral gyri. Although less severe, such changes were also observed in other brain regions, including the basal ganglia and substantia nigra. In the spinal cord, loss of anterior horn cells and degeneration of the corticospinal tract were evident. In addition, the affected regions exhibited neuronal cytoplasmic inclusions resembling neurofibrillary tangles. Immunostaining using antibodies against hyperphosphorylated tau and 4-repeat tau revealed widespread occurrence of neuronal and glial cytoplasmic inclusions in the central nervous system; the astrocytic tau lesions were unique, and different in morphology from astrocytic plaques in CBD, or tufted astrocytes in PSP. However, immunoblotting of frozen brain samples available in two cases revealed predominantly 4R tau, with the approximately 37-kDa and 33-kDa low-molecular mass tau fragments characteristic of CBD and PSP, respectively. No mutations were found in the tau gene in either of the two cases. Based on these clinicopathological, biochemical, and genetic findings, we consider that the present three patients form a distinct 4R tauopathy associated with sporadic FTLD.

[Clinical and pathological spectrum of TDP-43 associated ALS].

The molecular pathogenesis of amyotrophic lateral sclerosis (ALS) is unclear. TAR DNA-binding proteins of 43 KDa (TDP-43) immunopositive cytoplasmic inclusions have been found in glia and neurons of ALS patients. The discovery of TDP-43 mutations in ALS patients indicates a direct role of TDP-43 in ALS. More than 30 mutations in the TDP-43 gene have been identified in patients with familial and sporadic ALS. ALS with a TDP-43 mutation is classified as ALS-10. The clinical features of ALS-10 are quite similar to those of sporadic ALS. Furthermore, the neuropathological findings for ALS-10, including TDP-43 immunopositive inclusions and Bunina bodies, are identical to those in sporadic ALS. Most of the mutations are located in the C-terminus of TDP-43, which may function as a binding domain of heterogeneous nuclear ribonucleoprotein. Frontotemporal lobar degeneration: FTLD and FTLD/MND (motor neuron disease) also have TDP-43 immunopositive inclusions. These disorders have been named as TDP-43 proteinopathy. However, patients with TDP-43 mutations rarely develop FTLD. Causative genes for familial FTLD and FTLD/MND are not linked to the TDP-43 gene. Thus, other factors may contribute to the TDP-43 pathology in these diseases. Further analysis is required to elucidate the molecular mechanism of ALS-10 and TDP-43 proteinopathy.

[Neuropathological similarities and differences between frontotemporal lobar degeneration with ubiquitin inclusions and amyotrophic lateral sclerosis with dementia].

Findings of clinical, neuropathological and biochemical studies have supported the idea that frontotemporal lobar degeneration with ubiquitin inclusions (FTLD-U) and amyotrophic lateral sclerosis (ALS) are part of a neurological disease spectrum. This concept is now further strengthened by the recent discovery of a 43-kDa transactivating responsive sequence DNA-binding protein (TDP-43) as a key component of the underlying neuropathology of FTLD-U, ALS with dementia (ALS-D) and ALS. Here we describe the clinicopathological features of selected autopsy cases belonging to this disease spectrum, and discuss the neuropathological similarities and differences between FTLD-U and ALS-D, with special reference to the morphology, distribution and density of ubiquitin/TDP-43-positive abnormal structures, along with a review of the literature.

Selective occurrence of TDP-43-immunoreactive inclusions in the lower motor neurons in Machado-Joseph disease.

Pathological transactivation-responsive DNA-binding protein 43 (TDP-43) has been identified as a component of ubiquitinated inclusions in frontotemporal lobar degeneration with motor neuron disease, as well as in sporadic and some forms of familial amyotrophic lateral sclerosis. To clarify whether pathological TDP-43 is present in other neurodegenerative diseases involving the motor neuron system, we immunohistochemically examined the brain and spinal cord affected by two CAG repeat (polyglutamine) diseases, Machado-Joseph disease (MJD) and spinal and bulbar muscular atrophy (SBMA), using polyclonal antibody against TDP-43. In all the MJD cases, TDP-43-immunoreactive (ir) neuronal cytoplasmic inclusions (NCIs), although few in number, were found only in the lower motor neurons in the brainstem and spinal cord. TDP-43-ir NCIs appeared as linear wisp-like, skein-like, or thick, somewhat rod-like bodies. These inclusions were also visualized with antibodies against phosphoserines 409 and 410 of TDP-43, and ubiquitin, but were not recognized by antibody against expanded polyglutamine stretches or ataxin-3. The ultrastructure of the TDP-43-ir NCIs was similar to that of the inclusions seen in sporadic ALS, consisting of bundles of parallel filaments. None of the SBMA cases showed abnormal TDP-43 immunoreactivity in any of the regions examined. Immunoblot analysis failed to recognize hyperphosphorylated TDP-43 at ~23 kDa in two MJD cases examined. However, the immunohistochemical findings strongly suggested that in MJD, in addition to the polyglutamine-dependent disease process, TDP-43-related pathogenesis is associated with degeneration and death of the lower motor neurons.

Sporadic amyotrophic lateral sclerosis: Widespread multisystem degeneration with TDP-43 pathology in a patient after long-term survival on a respirator.

It has been reported that widespread multisystem degeneration can occur in patients with sporadic amyotrophic lateral sclerosis (SALS) who have survived for long periods with artificial respiratory support (ARS). We report a case of SALS of 8 years and 8 months duration in a 71-year-old woman, who received ARS for 7 years and 8 months. In this patient, the symptoms at the early stage were those of typical ALS, and a totally locked-in state with frontal lobe atrophy appeared a few years after the start of ARS. At autopsy, marked atrophy of the frontal lobe and brainstem tegmentum was evident. Microscopically, widespread multisystem degeneration with obvious neuronal loss was a feature. Bunina bodies and ubiquitinated inclusions were observed in the remaining lower motor neurons. Of interest was that Lewy body-like hyaline inclusions (LBHIs), which were later shown to be immunnoreactive (ir) for 43-kDa TAR DNA-binding protein (TDP-43) and ubiquitin, were also detected in neurons in various regions of the nervous system, including the lower and upper motor neuron nuclei. The distributions of neurons with TDP-43-ir and ubiquitin-ir cytoplasmic inclusions were also widespread in the nervous system, and in each region, the numbers of these neurons were apparently larger than those of neurons with LBHIs. Importantly, double-labeling immunofluorescence revealed that the widespread TDP-43-ir inclusions were often ubiqutinated. In conclusion, the entire pathological picture appeared to correspond well to the patient's long-standing, progressive disease, including the TDP-43 pathology with ubiquitination. These findings further strengthen the idea that TDP-43 abnormality is closely associated with the pathogenesis of SALS.

Sporadic amyotrophic lateral sclerosis of long duration is associated with relatively mild TDP-43 pathology.

Recently, sporadic amyotrophic lateral sclerosis (SALS), a fatal neurological disease, has been shown to be a multisystem proteinopathy of TDP-43 in which both neurons and glial cells in the central nervous system are widely affected. In general, the natural history of SALS is short (<5 years). However, it is also known that a few patients may survive for 10 years or more, even without artificial respiratory support (ARS). In the present study using TDP-43 immunohistochemistry, we examined various regions of the nervous system in six patients with SALS of long duration (10-20 years) without ARS, in whom lower motor-predominant disease with Bunina bodies and ubiquitinated inclusions (UIs) in the affected lower motor neurons was confirmed. One case also showed UIs in the hippocampal dentate granule cells (UDG). In all cases, except one with UDG, the occurrence of TDP-43-immunoreactive (ir) neuronal cytoplasmic inclusions (NCIs) was confined to a few regions in the spinal cord and brainstem, including the anterior horns. In one case with UDG, TDP-43-ir NCIs were also detected in the substantia nigra, and some regions of the cerebrum, including the hippocampal dentate gyrus (granule cells). The number of neurons displaying NCIs in each region was very small (1-3 per region, except the dentate gyrus). On the other hand, the occurrence of TDP-43-ir glial cytoplasmic inclusions (GCIs) was more widespread in the central nervous system, including the cerebral white matter. Again, however, the number of glial cells displaying GCIs in each region was very small (1-3 per region). In conclusion, compared to the usual form of SALS, TDP-43 pathology shown in SALS of long duration was apparently mild in degree and limited in distribution, corresponding to the relatively benign clinical courses observed. It is now apparent that SALS of long duration is actually part of a TDP-43 proteinopathy spectrum.

Maturation process of TDP-43-positive neuronal cytoplasmic inclusions in amyotrophic lateral sclerosis with and without dementia.

To elucidate the maturation process of TDP-43-positive neuronal inclusions, we immunohistochemically and immunoelectron-microscopically examined multiple areas from the brain and spinal cord from ten patients with amyotrophic lateral sclerosis (ALS) and 25 control subjects. TDP-43 immunohistochemistry demonstrated three types of inclusions in ALS: skein-like, round, and dot-like inclusions. Skein-like inclusions were found in all cases of ALS. Dot-like inclusions were found in the anterior horn in seven cases of ALS, all of whom had round inclusions, but not in cases without round inclusions. In addition, careful examination revealed two types of diffuse punctate cytoplasmic staining: linear wisps and punctate granules. Linear wisps were present in all cases of ALS but in none of 25 controls. In contrast, punctate granules were detected in all cases of ALS as well as in five of 13 normal and in seven of 12 diseased controls. Immunoelectron-microscopy revealed that skein-like inclusions consisted of granule-associated parallel filaments. Round and dot-like inclusions were composed of granulo-filamentous structures. However, punctate granules corresponded to the mitochondria and were not immunostained with anti-ubiquitin, indicating that punctate granules represent cross-reaction. We assumed that linear wisps ("fine skein") aggregate as thicker and longer threads ("coarse skein"), whereas round inclusions arise from dot-like inclusions. These findings suggest that there are differences in the formation process between skein-like and round inclusions, despite the antigenic and ultrastructural similarities.

Sporadic amyotrophic lateral sclerosis: two pathological patterns shown by analysis of distribution of TDP-43-immunoreactive neuronal and glial cytoplasmic inclusions.

A nuclear protein, 43-kDa TAR DNA-binding protein (TDP-43), was recently identified as a component of the ubiquitinated inclusions (UIs) in frontotemporal lobar degeneration (FTLD-U) and sporadic amyotrophic lateral sclerosis (SALS). In the present study using immunohistochemistry, we examined various regions of the nervous system in a series of 35 SALS cases using a polyclonal antibody against TDP-43. Seven of the 35 cases had disease durations of more than 10 years with artificial respiratory support (ARS; duration: 69-156 months). In all cases, TDP-43-immunoreactive (ir) neuronal and glial cytoplasmic inclusions (NCIs and GCIs) were found together in many regions, including the histologically affected lower motor neuron nuclei. Cluster analysis of the distribution pattern of TDP-43-ir NCIs for cases without ARS (n = 28) identified two types (type 1, n = 16; type 2, n = 12). Type 2 was distinguished from type 1 by the presence of TDP-43-ir NCIs in the frontotemporal cortex, hippocampal formation, neostriatum and substantia nigra, and was significantly associated with dementia. Eleven of the 28 cases showed UIs in the hippocampal dentate granule cells, all of which had type-2 distribution pattern. Cases with ARS (n = 7) were also classified into the same types (type 1, n = 5; type 2, n = 2). Cases having type-1 distribution pattern (n = 21) showed no evident neuronal loss in most of the non-motor neuron nuclei where TDP-43-ir NCIs were present, whereas cases having type-2 distribution pattern (n = 14) often showed evident neuronal loss in the frontotemporal cortices, amygdaloid nuclei and substantia nigra. These findings indicate that SALS is a multisystem degenerative disease widely affecting both neurons and glial cells with a heterogeneous pattern of TDP-43-ir NCI distribution (SALS showing type-2 distribution pattern being closely linked to FTLD-U), and that long-term survival supported by a respirator has no apparent influence on the TDP-43 neuronal distribution pattern.

Patients homozygous and heterozygous for SNCA duplication in a family with parkinsonism and dementia.

BACKGROUND: Multiplication of the alpha-synuclein gene (SNCA) (OMIM 163890) has been identified as a causative mutation in hereditary Parkinson disease or dementia with Lewy bodies. OBJECTIVE: To determine the genetic, biochemical, and neuropathologic characteristics of patients with autopsy-confirmed autosomal dominant Lewy body disease, with particular reference to the dosage effects of SNCA. DESIGN: Four-generation family study. SETTING: Academic research. Patients We fractionated samples extracted from frozen brain tissues of 4 patients for biochemical characterization, followed by immunoblot analysis. MAIN OUTCOME MEASURES: We determined the dosages of SNCA and its surrounding genes by quantitative polymerase chain reaction analysis. RESULTS: Quantitative polymerase chain reaction analysis revealed that 3 patients were heterozygous for SNCA duplication and 1 patient was homozygous for SNCA duplication. The homozygous patient showed earlier age at onset and earlier death, with more severe cognitive impairment than the heterozygous patients. Biochemical analysis revealed that phosphorylated alpha-synuclein accumulated in the sarkosyl-insoluble urea-extracted fraction of the brains of the patients. CONCLUSIONS: Pathologically confirmed Lewy body disease clinically characterized by progressive parkinsonism and cognitive dysfunction is caused by SNCA duplication. The homozygous patient demonstrated the most severe phenotype, suggesting that SNCA dosage has a considerable effect on disease phenotype even within a family. SNCA duplication results in the hyperaccumulation of phosphorylated alpha-synuclein in the brains of patients.

TDP-43 mutation in familial amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder. Accumulating evidence has shown that 43kDa TAR-DNA-binding protein (TDP-43) is the disease protein in ALS and frontotemporal lobar degeneration. We previously reported a familial ALS with Bumina bodies and TDP-43-positive skein-like inclusions in the lower motor neurons; these findings are indistinguishable from those of sporadic ALS. In three affected individuals in two generations of one family, we found a single base-pair change from A to G at position 1028 in TDP-43, which resulted in a Gln-to-Arg substitution at position 343. Our findings provide a new insight into the molecular pathogenesis of ALS.

TDP-43-immunoreactive neuronal and glial inclusions in the neostriatum in amyotrophic lateral sclerosis with and without dementia.

TDP-43 is a major component of ubiquitin-positive, tau-negative inclusions in amyotrophic lateral sclerosis (ALS), and frontotemporal lobar degeneration. We immunohistochemically examined the neostriatum from 14 cases of classic ALS (cALS), six cases of ALS with dementia (ALS-D), and 20 control subjects. TDP-43-positive, crescent or circular inclusions were found in neostriatal small neurons in 19 of 20 cases of ALS, but not in controls. Two types of inclusions were found in the large neurons: ubiquitin-positive, TDP-43-negative rod-like inclusions, and ubiquitin- and TDP-43-positive pleomorphic inclusions. The latter were specific to ALS; they were found in seven cases of cALS and in all of ALS-D. TDP-43-positive glial inclusions were also found in 12 cases of cALS and in all of ALS-D. These TDP-43-positive neuronal and glial inclusions were more numerous in ALS-D than cALS. In ALS-D, neuronal loss in the substantia nigra was found in all the cases, whereas mild gliosis without obvious neuronal loss was noted in the neostriaum in only two cases. These findings suggest that the neostriatum is also involved in the disease process of ALS with and without dementia.

A case of congenital supratentorial tumor: atypical teratoid/rhabdoid tumor or primitive neuroectodermal tumor?

Two embryonal CNS tumors, atypical teratoid/rabdoid tumor (AT/RT) and primitive neuroectodermal tumor (PNET), may be confused with each other and misdiagnosed. Here we report an infant with a congenital supratentorial tumor, which was detected by fetal MRI at 37 weeks gestation. On routine histological examination, the tumor was composed mainly of small undifferentiated cells, among which many rhabdoid cells and occasional sickle-shaped embracing cells were observed. No mesenchymal or epithelial areas were evident. Our impression was that the tumor was an atypical example of AT/RT. Immunohistochemically, almost all the tumor cells were strongly positive for vimentin. However, epithelial membrane antigen was notably negative, and most of the tumor cell nuclei were clearly positive for INI1. In addition, many tumor cells were positive for neurofilament protein. There were also occasional small areas containing many tumor cells positive for glial fibrillary acidic protein. Finally, a diagnosis of PNET, with a rhabdoid phenotype and expression of neuronal and glial markers, was made. In the present case, application of INI1 immunostaining was very helpful for distinguishing PNET from AT/RT.

Venous congestive myelopathy of the cervical spinal cord: an autopsy case showing a rapidly progressive clinical course.

We report a rapidly progressive myelopathy in a 74-year-old Japanese man who was admitted to our hospital with a 4-month history of progressive gait disturbance and died of pneumonia followed by respiratory failure on the 22nd day of admission. During the course of his illness, magnetic resonance imaging (MRI) revealed intramedullary lesions with edematous swelling from the medulla oblongata to the spinal cord at the level of the fourth vertebra. After administration of contrast medium, the ventral portion of the lesion was mildly and irregularly enhanced and a dilated vessel was recognized along the ventral surface of the upper cervical cord. At autopsy, ischemic changes were observed in the upper-to-middle cervical cord segments, with so-called arterialized veins in the subarachnoid space. No neoplastic lesions were found within or outside the brain and spinal cord. These pathological findings were essentially those of venous congestive myelopathy (VCM) associated with dural arteriovenous fistulae (AVF), formerly known as Foix-Alajouanine syndrome. VCM associated with dural AVF, which is now considered to be treatable in the early stages, is rare found in the cervical spinal cord. The present autopsy case, with MRI findings, provides further information that might be useful for recognition and diagnosis.

TDP-43 immunoreactivity in neuronal inclusions in familial amyotrophic lateral sclerosis with or without SOD1 gene mutation.

Recently, 43-kDa TAR DNA-binding protein (TDP-43) was identified as a component of ubiquitinated inclusions (UIs) in sporadic amyotrophic lateral sclerosis (SALS). To clarify whether TDP-43 immunoreactivity is present in neuronal inclusions in familial ALS (FALS), we examined immunohistochemically the brains and spinal cords from four cases of FALS, two with Cu/Zn superoxide dismutase (SOD1) gene mutation and two without, together with three cases of SALS and three control subjects, using two antibodies, one polyclonal and one monoclonal, against TDP-43. Neuropathologically, the SOD1-related FALS cases were characterized by Lewy body-like hyaline inclusions (LBHIs) in the lower motor neurons. On the other hand, the SOD1-unrelated FALS cases showed degeneration restricted to the upper and lower motor neuron systems, with Bunina bodies (BBs) and UIs in the lower motor neurons, being indistinguishable from SALS. No cytoplasmic TDP-43 immunoreactivity was observed in the control subjects or SOD1-related FALS cases; LBHIs were ubiquitinated, but negative for TDP-43. UIs observed in the SALS and SOD1-unrelated FALS cases were clearly positive for TDP-43. BBs were negative for this protein. Interestingly, in these SALS and FALS cases, glial cells were also found to have cytoplasmic TDP-43-positive inclusions. These findings indicate that the histological and molecular pathology of SALS can occur as a phenotype of FALS without SOD1 mutation.

Familial amyotrophic lateral sclerosis: a SOD1-unrelated Japanese family of bulbar type with Bunina bodies and ubiquitin-positive skein-like inclusions in lower motor neurons.

We describe a new family with adult onset amyotrophic lateral sclerosis (FALS), in which the disease was characterized clinically by relatively rapid progression of bulbar symptoms. Gene analysis of Cu/Zn superoxide dismutase (SOD1) performed in one patient showed no mutations. Autopsy of another patient demonstrated degenerative changes restricted to the upper and lower motor neuron systems; no evident changes were observed in the posterior column, Clarke's column or spinocerebellar tracts. The presence of Bunina bodies and ubiquitin-positive skein-like inclusions in the lower motor neuron was of considerable interest. Cases of FALS with such pathological features are quite rare in the literature. Identification of the gene responsible for the disease is desirable in order to shed further light on the molecular pathology of not only familial, but also sporadic, ALS.

Sporadic four-repeat tauopathy with frontotemporal degeneration, parkinsonism and motor neuron disease.

We report a sporadic tauopathy of 6-year duration in a 76-year-old woman. Her initial symptoms were asymmetrical parkinsonism and muscle weakness, with apraxia appearing 2 years later. The brain showed frontal and temporal cerebral atrophy; severe neuronal loss and gliosis were observed in the precentral cortex (loss of Betz cells was also evident) and premotor area, and in the medial temporal lobe, including the temporal tip, amygdala, and hippocampal CA1-subiculum border zone. The substantia nigra showed moderate neuronal loss and gliosis. In the spinal cord, loss of the anterior horn cells and degeneration of the corticospinal tracts were a characteristic feature. In addition, in the affected regions, the remaining neurons were often found to contain intracytoplasmic inclusions resembling neurofibrillary tangles. Tau immunostaining revealed widespread glial-predominant lesions in the cerebral gray and white matter. In contrast, predominance of neuronal lesions (pretangles/tangles) was a feature in the subcortical gray matter, including the spinal cord. The remaining upper and lower motor neurons were also affected by tau pathology. Accumulated tau in these glial cells and neurons was clearly recognized by a specific antibody against four-repeat (4R) tau. The ultrastructural presence of tau-positive tubular structures was confirmed in the glial cells and neurons (tangles). Immunoblotting of a frozen frontal lobe sample revealed accumulation of 4R-predominant tau isoforms. No mutations were found in the tau gene. These findings indicate that a sporadic 4R tauopathy can cause frontotemporal degeneration, parkinsonism, and motor neuron disease. The present case could represent a new clinicopathological phenotype of non-familial tauopathy.

Is motor neuron disease-inclusion dementia a forme fruste of amyotrophic lateral sclerosis with dementia? An autopsy case further supporting the disease concept.

We report the autopsy findings of a 62-year-old man who exhibited progressive FTD 10 years before the appearance of muscle weakness and wasting, and who died approximately 11 years after onset of the symptoms. Degeneration and atrophy of the frontal and temporal lobes, which contained ubiquitin-positive neuronal inclusions and dystrophic neurites, were evident. Circumscribed degeneration affecting the hippocampal CA1-subiculum border zone was also a feature. Moreover, degeneration was present in both the upper and lower motor neuron systems, the latter being more severely affected. A few lower motor neurons were found to contain the cytoplasmic inclusions characteristic of ALS (i.e. Bunina bodies and ubiquitin-positive skeins). Also of interest was the presence of pallidonigroluysian atrophy, which appeared to be responsible for the chorea-like involuntary movements that developed in this patient approximately 2 months before death. The clinical and pathological features of our patient further support the idea that motor neuron disease-inclusion dementia (MND-ID), which has been classified as a pathological subgroup of FTD, is a forme fruste of ALS with dementia. In other words, if patients with MND-ID live long enough, they may develop ALS.

Frontotemporal dementia with co-occurrence of astrocytic plaques and tufted astrocytes, and severe degeneration of the cerebral white matter: a variant of corticobasal degeneration?

We report two patients who exhibited frontotemporal dementia (FTD) with unusual neuropathological features. The ages of the patients at death were 65 and 67 years, the disease durations were 6 and 5 years, and the clinical diagnoses were Pick's disease and corticobasal degeneration (CBD), respectively. At autopsy, both cases exhibited neuropathological findings compatible with those of CBD, including atrophy of the frontal and parietal lobes, neuronal loss and gliosis in the cortical and subcortical regions, and presence of cortical ballooned neurons and astrocytic plaques (APs). In both cases, immunoblotting of insoluble tau exhibited the pattern of selective accumulation of four-repeat tau, a finding that is also compatible with CBD. However, severe degeneration was evident in the frontal and parietal white matter in both cases. Moreover, a striking finding was the widespread presence in the affected cortex of tufted astrocytes (TAs), which are characteristic of progressive supranuclear palsy (PSP). Neither co-occurrence of APs and TAs nor severe degeneration of the cerebral white matter is a feature of either CBD or PSP. No mutations were found in the tau gene in either case. In conclusion, the possibility that these two cases represent a new neuropathological phenotype of non-familial FTD rather than simply a variant of CBD cannot be completely excluded.