Therapeutic strategy for Fabry disease by intravenous administration of adeno-associated virus 2 or 9 in α-galactosidase A-deficient mice.

BACKGROUND: Fabry disease (FD) is an inherited lysosomal storage disease caused by deficiency of α-galactosidase A (α-Gal A) encoded by the GLA gene. The symptoms of FD occur as a result of the accumulation of globotriaosylceramide (Gb3), comprising a substrate of α-Gal A, in the organs. Adeno-associated virus (AAV)-mediated gene therapy is a promising treatment for FD. METHODS: α-Gal A knockout (GLAko) mice were injected intravenously with AAV2 (1 × 1011 viral genomes [vg]) or AAV9 (1 × 1011 or 2 × 1012 vg) vectors carrying human GLA (AAV-hGLA), and plasma, brain, heart, liver and kidney were tested for α-Gal A activity. The vector genome copy numbers (VGCNs) and Gb3 content in each organ were also examined. RESULTS: The plasma α-Gal A enzymatic activity was three-fold higher in the AAV9 2 × 1012 vg group than wild-type (WT) controls, which was maintained for up to 8 weeks after injection. In the AAV9 2 × 1012 vg group, the level of α-Gal A expression was high in the heart and liver, intermediate in the kidney, and low in the brain. VGCNs in the all organs of the AAV9 2 × 1012 vg group significantly increased compared to the phosphate-buffered-saline (PBS) group. Although Gb3 in the heart, liver and kidney of the AAV9 2 × 1012 vg was reduced compared to PBS group and AAV2 group, and the amount of Gb3 in the brain was not reduced. CONCLUSIONS: Systemic injection of AAV9-hGLA resulted in α-Gal A expression and Gb3 reduction in the organs of GLAko mice. To expect a higher expression of α-Gal A in the brain, the injection dosage, administration route and the timing of injection should be reconsidered.

Herpes Zoster Ophthalmicus Initially Diagnosed As Cluster Headache, Complicated by Delayed Eruption.

Herpes zoster ophthalmicus (HZO) manifests as a consequence of the reactivation of the Varicella-zoster virus (VZV) and primarily affects the ophthalmic division of the trigeminal nerve. Identification of the vesicular eruption is central to the diagnostic process; however, the delayed manifestation of this cutaneous phenomenon poses a challenge to timely and accurate diagnosis. This report elucidates the case of a 61-year-old Japanese male with painful trigeminal neuropathy attributed to VZV that was initially diagnosed as cluster headache, mainly due to the delayed cutaneous eruption. Contrary to the expected pattern of cluster headache presentations, there was no discernible fluctuation in headache severity. The transient improvement of symptoms following interventions tailored for cluster headache management, including pure oxygen inhalation and subcutaneous sumatriptan injection, inadvertently contributed to a delay in accurate diagnosis. The importance of distinguishing HZO from cluster headache is emphasized, particularly in cases involving elderly patients or those with persistent cephalo-ophthalmalgia without the characteristic fluctuation of symptoms. In cases where clinical suspicion of HZO is raised, cerebrospinal fluid analysis should be performed. This approach is consistent with the overall goal of facilitating a prompt and accurate diagnosis.

Therapeutic Strategy for Fabry Disease by Intravenous Administration of Adeno-Associated Virus 9 in a Symptomatic Mouse Model.

Fabry disease (FD) is an inherited lysosomal storage disease caused by deficiency of α-galactosidase A (α-Gal A), an enzyme that hydrolyzes glycosphingolipids in lysosome. Accumulation of glycosphingolipids, mainly globotriaosylceramide (Gb3) in tissues, induces cellular dysfunction leading to multi-organ disorder. Gene therapy is a promising strategy that can overcome these problems, and virus vectors such as adeno-associated virus (AAV) have been used for study on gene therapy. We used human Gb3 synthetase-transgenic (TgG3S)/α-Gal A knockout (GLAko) mice. TgG3S/GLAko mice have elevated Gb3 accumulation in the major organs compared with GLAko mice, which have been widely used as a model for FD. At the age of 6 weeks, male TgG3S/GLAko were injected with 2 × 1012 vector genome AAV9 vectors containing human α-Gal A cDNA. Eight weeks after intravenous injection of AAV, α-Gal A enzymatic activity was elevated in the plasma, heart, and liver of TgG3S/GLAko mice to levels corresponding to 224%, 293%, and 105% of wild-type, respectively. Gb3 amount 8 weeks after AAV injection in the heart and liver of this group was successfully reduced to levels corresponding to 16% and 3% of untreated TgG3S/GLAko mice. Although the brain and kidney of AAV9-treated TgG3S/GLAko mice showed no significant increases in α-Gal A activity, Gb3 amount was smaller than untreated littermates (48% and 44%, respectively). In this study, systemic AAV administration did not show significant extension of the lifespan of TgG3S/GLAko mice compared with the untreated littermates. The timing of AAV injection, capsid choice, administration route, and injection volume may be important to achieve sufficient expression of α-Gal A in the whole body for the amelioration of lifespan.

[Issues of transition support to adulthood and the practices of pediatric-adult healthcare transition in neurological diseases].

A workshop of the Special Committee on Measures for Transition from Pediatric to Adult Health Care, the Japanese Society of Neurology was held to discuss various issues and practices involved in healthcare transition. The following points were addressed: (1) the history of, and issues involved in, promoting support for patients requiring medical care, (2) cooperation between pediatric medical centers and university hospitals, (3) collaboration between pediatrics and neurology in medical and rehabilitation facilities, and (4) a questionnaire survey of members of the Japanese Society of Neurology. The reasons for extreme difficulties in pediatric-adult healthcare transition for patients with neurological diseases, especially those who require continuous intensive medical care over a long period of time, include the difference in the operating systems of pediatric and adult departments, in addition to the difference in the diseases treated during childhood and adulthood. For holistic transition support, it is necessary to strengthen cooperation not only among medical professionals, but also among multiple professions, as well as between local communities and government.

Long-term efficacy of intrathecal cyclodextrin in patients with Niemann-Pick disease type C.

BACKGROUND AND OBJECTIVES: Niemann-Pick type C (NPC) is a rare lysosomal storage disease characterized by hepatosplenomegaly and progressive neurological deterioration due to abnormal intracellular cholesterol transport. Cyclic oligosaccharide 2-hydroxypropyl-ß-cyclodextrin (HPBCD) is an effective treatment for NPC; however, few reports have shown its long-term efficacy and safety. To demonstrate long-term efficacy and safety of intrathecal HPBCD (IT-HPBCD) treatment for NPC, we herein reports five patients with NPC treated using IT-HPBCD for 4-11 years. CASES AND RESULTS: Patients' ages at the onset ranged from 1.5 to 20 years. Notably, all patients showed rapid disease progression despite treatment with miglustat before IT-HPBCD treatment. Similarly, some patients showed transient improvement; however, all patients' conditions stabilized after long-term IT-HPBCD therapy. Mild-to-moderate hearing loss was observed in three patients. Furthermore, long-term treatment with IT-HPBCD may suppress neurological deterioration in patients with NPC; however, patients still experience some disease progression. CONCLUSIONS: Long-term treatment with IT-HPBCD may suppress neurological deterioration in patients with NPC; however, the treatment outcome is dependent on the neurological status at the time of diagnosis, and disease progression is not completely inhibited. Awareness of the disease and newborn screening is needed for earlier disease detection. In addition, further optimization of the treatment protocol and additional treatments are needed to improve patient outcomes.

[Current practices of transition from pediatric to adult health care for patients with neurological disease: promote the cooperation between child and adult neurologists].

The Special Committee for Measures Against Transition from Pediatric to Adult Health Care of the Japanese Society of Neurology, which consists of child and adult neurologists, started to tackle the issues of pediatric to adult health care transition for patients with neurological disease in July 2020. The Committee held a workshop with a theme of "cooperation between child and adult neurologists," which is a critical issue in the pediatric to adult health care transition. To solve the many problems in the pediatric to adult health care transition, it is crucial that child and adult neurologists and primary care physicians cooperate on the following issues: preparing child neurologists for the transition, encouraging adult neurologists to study child neurology, promoting the formation of multidisciplinary teams, improving the medical system and medical fees, appealing to governmental agencies for issues of community health care and welfare services.

Whole Blood Spermine/Spermidine Ratio as a New Indicator of Sarcopenia Status in Older Adults.

Early diagnosis and therapeutic intervention improve the quality of life and prognosis of patients with sarcopenia. The natural polyamines spermine and spermidine are involved in many physiological activities. Therefore, we investigated blood polyamine levels as a potential biomarker for sarcopenia. Subjects were Japanese patients >70 years of age who visited outpatient clinics or resided in nursing homes. Sarcopenia was determined based on muscle mass, muscle strength, and physical performance according to the criteria of the Asian Working Group for Sarcopenia (2019). The analysis included 182 patients (male: 38%, age: 83 [76-90] years). Spermidine levels were higher (p = 0.002) and the spermine/spermidine ratio was lower (p < 0.001) in the sarcopenia group than in the non-sarcopenia group. Polyamine concentration analysis showed that the odds ratios for age and spermidine changed in parallel with sarcopenia progression, and the odds ratio for the spermine/spermidine ratio changed inversely with the degree of sarcopenia progression. Additionally, when the odds ratio was analyzed with spermine/spermidine instead of polyamine concentrations, only for spermine/spermidine, the odds ratio values varied in parallel with the progression of sarcopenia. Based on the present data, we believe that the blood spermine/spermidine ratio may be a diagnostic indicator of risk for sarcopenia.

Positive Correlation between Relative Concentration of Spermine to Spermidine in Whole Blood and Skeletal Muscle Mass Index: A Possible Indicator of Sarcopenia and Prognosis of Hemodialysis Patients.

Several mechanisms strictly regulate polyamine concentration, and blood polyamines are excreted in urine. This indicates polyamine accumulation in renal dysfunction, and studies have shown increased blood polyamine concentrations in patients with renal failure. Hemodialysis (HD) may compensate for polyamine excretion; however, little is known about polyamine excretion. We measured whole-blood polyamine levels in patients on HD and examined the relationship between polyamine concentrations and indicators associated with health status. Study participants were 59 hemodialysis patients (median age: 70.0 years) at Minami-Uonuma City Hospital and 26 healthy volunteers (median age: 44.5 years). Whole-blood spermidine levels were higher and spermine/spermidine ratio (SPM/SPD) was lower in hemodialysis patients. Hemodialysis showed SPD efflux into the dialysate; however, blood polyamine levels were not altered by hemodialysis and appeared to be minimally excreted. The skeletal muscle mass index (SMI), which was positively correlated with hand grip strength and serum albumin level, was positively correlated with SPM/SPD. Given that sarcopenia and low serum albumin levels are reported risk factors for poor prognosis in HD patients, whole blood SPM/SPD in hemodialysis patients may be a new indicator of the prognosis and health status of HD patients.

[Healthcare Transition in Outpatient Clinics].

Many cases of healthcare transition were referred to the Department of Neurology in our local core hospital with an emergency and critical care center, owing to the relocation of a nearby children's medical center. Most patients presented epilepsy with difficulty in controlling seizures or were children with severe mental and physical disabilities requiring medical care. During the transition, multidisciplinary collaboration centered on the medical consultation office was conducted. After the transition, many patients were transported to emergency rooms for seizures, pneumonia, and other infectious diseases. Education, advanced care planning, and regional collaboration were some of the issues in the process.

[Perspective on transition from pediatric to adult health care for patients with neurological disease: current situation and issues].

An improvement in efficacy treatment and development of the social support system has led to many patients with neurological disease being able to reach adulthood. Therefore health care for life from pediatrics to adulthood has become necessary. The Special Committee for Measures Against Transition from Pediatric to Adult Health Care of the Japanese Society of Neurology officially started to examine the current situation and issues of transition from pediatric to adult health care in July 2020. Pediatric neurologists and adult neurologists have an awareness of this issue of constructing a better transition from pediatric to adult health care. However, there are some tasks that need to be resolved in the medical system. We intend to improve the understanding of transition and assessment of medical service fees for transition in cooperation with the Japanese Society of Neurology and the Japanese Society of Child Neurology.

Alanine transaminase is predominantly increased in the active phase of anti-HMGCR myopathy.

Autoantibodies against 3­hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and the signal recognition particle (SRP) are representative antibodies causing immune-mediated necrotizing myopathies (IMNM), called as anti-HMGCR and anti-SRP myopathies, respectively. Here, we analyzed the differences in routine blood test results between 56 anti-HMGCR and 77 anti-SRP myopathy patients. A higher alanine transaminase (ALT) level and a lower aspartate transaminase (AST)/ALT ratio were observed in anti-HMGCR myopathy patients [ALT, 265.7 ±â€¯213.3 U/L (mean ± standard deviation); AST/ALT ratio, 0.88 ±â€¯0.32] than in anti-SRP-myopathy patients (ALT, 179.3 ±â€¯111.2 U/L, p < 0.05; AST/ALT ratio, 1.28 ±â€¯0.40, p < 0.01). In the active phase, anti-HMGCR myopathy often showed ALT predominance, whereas anti-SRP myopathy often showed AST predominance. In addition, there were differences in erythrocyte sedimentation rate (ESR), total cholesterol (TChol) level, and high-density lipoprotein (HDL) level between anti-HMGCR and anti-SRP myopathies (ESR: HMGCR, 24.4 ±â€¯20.8 mm/1 h; SRP, 35.7 ±â€¯26.7 mm/1 h, p = 0.0334; TChol: HMGCR, 226.7 ±â€¯36.6 mg/dL; SRP, 207.6 ±â€¯40.8 mg/dL, p = 0.0163; HDL: HMGCR, 58.4 ±â€¯13.9 mg/dL; SRP, 46.2 ±â€¯17.3 mg/dL, p < 0.01). Additional studies on the differences in routine blood test results may further reveal the pathomechanisms of IMNM.

[Autopsy case of SCA2 with Parkinsonian phenotype].

This is the first autopsy case of SCA2 with parkinsonian phenotype. At the age of 46, the patient got symptoms of parkinsonism to which anti-parkinsonian drugs were effective. He had mosaic 38, 40 CAG repeat expansions on chromosome 12q23-24, being diagnosed as SCA2, and his mother and his son also had CAG expansions on the same locus. In addition to parkinsonism, he also exhibited autonomic disturbance, dementia, and mild cerebellar ataxia Brain images revealed severe atrophy of pons and medulla oblongata, resembling MSA-C. HVA and 5-HIAA were reduced in the cerebrospinal fluid, and the heart-mediastinum (H/M) ratio in myocardial 123I-MIBG cintigram was decreased, which suggested Lewy body pathology. He died at the age of 75 and the autopsy revealed atrophy of the olivo-ponto-cerebellar (OPC) system and substantia nigra which was compatible to SCA2, although the OPC system atrophy was less severe than formerly reported SCA2 cases. The degrees of atrophy of the OPC system and substantia nigra might explain the predominancy of clinical symptoms. Anti-1C2 positive inclusions in the pontine nuclei, inferior olive nuclei, cerebellum and substantia nigra confirmed a polyglutamine disease. In addition, there were the anti-phosphorylated alpha-synuclein positive, Lewy body related pathological changes in the substantia nigra, the locus ceruleus, the dorsal motor nuclei of vagus, and the sympathetic nerve in the myocardium. Major genetic abnormalities related to Parkinson disease were not detected. As another case of SCA2 with Lewy body pathology was reported in Japan, the coexistence of SCA2 and Lewy body pathology may not be accidental. Since myocardial MIBG scincigram can predict Lewy body pathology, we should seek more clinical cases of SCA2 with Lewy body pathology.

Reperfusion therapy of acute ischemic stroke in an all-in-one resuscitation room called a hybrid emergency room.

Acute ischemic stroke (AIS) caused by major vessel occlusion has potentially poor outcomes. Early successful recanalization after symptom onset is an important factor for favorable outcomes of AIS. We present the case of a 74-year-old man with AIS who underwent the entire process from diagnosis to thrombolysis and endovascular treatment in a hybrid emergency room (ER) equipped with a multidetector computed tomography (CT) scanner and an angiography suite set-up. A hybrid ER can facilitate evaluation and definitive interventions in patients with AIS more quickly and safely and in one place, without the requirement for transfer to a CT scanner or angiography suite set-up. In the present case, the door-to-puncture time and door-to-reperfusion time were 85 and 159 min, respectively, which were shorter than those in the group conventionally treated for stroke in our institution. Further study is needed to confirm the effect of the hybrid ER system.

Noncoding CGG repeat expansions in neuronal intranuclear inclusion disease, oculopharyngodistal myopathy and an overlapping disease.

Noncoding repeat expansions cause various neuromuscular diseases, including myotonic dystrophies, fragile X tremor/ataxia syndrome, some spinocerebellar ataxias, amyotrophic lateral sclerosis and benign adult familial myoclonic epilepsies. Inspired by the striking similarities in the clinical and neuroimaging findings between neuronal intranuclear inclusion disease (NIID) and fragile X tremor/ataxia syndrome caused by noncoding CGG repeat expansions in FMR1, we directly searched for repeat expansion mutations and identified noncoding CGG repeat expansions in NBPF19 (NOTCH2NLC) as the causative mutations for NIID. Further prompted by the similarities in the clinical and neuroimaging findings with NIID, we identified similar noncoding CGG repeat expansions in two other diseases: oculopharyngeal myopathy with leukoencephalopathy and oculopharyngodistal myopathy, in LOC642361/NUTM2B-AS1 and LRP12, respectively. These findings expand our knowledge of the clinical spectra of diseases caused by expansions of the same repeat motif, and further highlight how directly searching for expanded repeats can help identify mutations underlying diseases.

Lewy body pathology involves cutaneous nerves.

Involvement of the peripheral autonomic nervous system is a core feature of Lewy body (LB) diseases, including Parkinson disease (PD), PD with dementia, and dementia with LBs. To investigate the potential use of skin biopsy for the diagnosis of LB diseases, we assessed anti-phosphorylated alpha-synuclein immunoreactivity in peripheral nerves in samples of skin from the abdominal wall and flexor surface of the upper arm in 279 prospectively studied consecutively autopsied patients whose data were registered at the Brain Bank for Aging Research between 2002 and 2005. Positive immunoreactivity was demonstrated in the unmyelinated fibers of the dermis in 20 of 85 patients with LB pathology in the CNS and the adrenal glands, the latter representing a substitute for peripheral autonomic nervous system sympathetic ganglia; no reactivity was seen in 194 patients without CNS LB pathology. In 142 retrospectively studied patients autopsied from 1995 onward who had subclinical or clinical LB disease, the sensitivity of the positive skin immunoreactivity was 70% in PD and PD with dementia and 40% in dementia with LBs. Skin immunoreactivity was absent in cases of multiple-system atrophy, progressive nuclear palsy, and corticobasal degeneration. We demonstrate for the first time that the skin is involved and may be a highly specific and useful biopsy site for the pathological diagnosis of LB diseases.

Incidence and extent of Lewy body-related alpha-synucleinopathy in aging human olfactory bulb.

We investigated the incidence and extent of Lewy body (LB)-related alpha-synucleinopathy (LBAS) in the olfactory bulb (OB) in 320 consecutive autopsy patients from a general geriatric hospital (mean age, 81.5 +/- 8.5 years). Paraffin sections were immunostained with anti-phosphorylated alpha-synuclein, tyrosine hydroxylase, phosphorylated tau, and amyloid beta antibodies. LBAS was found in 102 patients (31.9%) in the central nervous system, including the spinal cord; the OB was involved in 85 (26.6%). Among these 85 patients, 2 had LBAS only in the anterior olfactory nucleus, 14 in the peripheral OB only, and 69 in both areas. In 5 patients, Lewy bodies were found only in the OB by hematoxylin and eosin stain; 3 of these patients had Alzheimer disease, and all had LBAS. Very few tyrosine hydroxylase-immunoreactive periglomerular cells exhibited LBAS. All 35 LBAS patients with pigmentation loss in the substantia nigra had LBAS in the OB. LBAS in the amygdala was more strongly correlated with LBAS in the anterior olfactory nucleus than with that in the OB periphery. LBAS did not correlate with systemic tauopathy or amyloid beta amyloidosis. These results indicate a high incidence of LBAS in the aging human OB; they also suggest that LBAS extends from the periphery to the anterior olfactory nucleus and results in clinical manifestations of LB disease.

Expansions of intronic TTTCA and TTTTA repeats in benign adult familial myoclonic epilepsy.

Epilepsy is a common neurological disorder, and mutations in genes encoding ion channels or neurotransmitter receptors are frequent causes of monogenic forms of epilepsy. Here we show that abnormal expansions of TTTCA and TTTTA repeats in intron 4 of SAMD12 cause benign adult familial myoclonic epilepsy (BAFME). Single-molecule, real-time sequencing of BAC clones and nanopore sequencing of genomic DNA identified two repeat configurations in SAMD12. Intriguingly, in two families with a clinical diagnosis of BAFME in which no repeat expansions in SAMD12 were observed, we identified similar expansions of TTTCA and TTTTA repeats in introns of TNRC6A and RAPGEF2, indicating that expansions of the same repeat motifs are involved in the pathogenesis of BAFME regardless of the genes in which the expanded repeats are located. This discovery that expansions of noncoding repeats lead to neuronal dysfunction responsible for myoclonic tremor and epilepsy extends the understanding of diseases with such repeat expansion.

[Neuropathological diagnosis of prion disease].

Neuropathological diagnosis of prion disease consists of sequence analysis of PRNP (prion protein gene), located on chromosome 20 and characterization and visualization of deposited proteinase K-resistant prion protein (PrP(Sc)). SNP at 129 locus (M/V) and Type 1 and Type 2 difference in Western blot analysis of PrP(Sc) from the postmortem brain influence the clinical and pathological presentations. Prion disease is classified into sporadic, hereditary and infectious subtypes, but PrP(Sc) from almost all the subtypes can transmit the disease to transgenic mice expressing human PRNP. Variant CJD, apparently derived from bovine spongiformic encephalopathy, requires shift in disease control strategy, in that PrP(Sc) is present in peripheral lymphatic organs.

Anti-TIF1-γ antibody and cancer-associated myositis: A clinicohistopathologic study.

OBJECTIVE: We aimed to analyze the clinical and histopathologic features of cancer-associated myositis (CAM) in relation to anti-transcriptional intermediary factor 1 γ antibody (anti-TIF1-γ-Ab), a marker of cancer association. METHODS: We retrospectively studied 349 patients with idiopathic inflammatory myopathies (IIMs), including 284 patients with pretreatment biopsy samples available. For the classification of IIMs, the European Neuromuscular Center criteria were applied. Patients with CAM with (anti-TIF1-γ-Ab[+] CAM) and without anti-TIF1-γ-Ab (anti-TIF1-γ-Ab[-] CAM) were compared with patients with IIM without cancers within and beyond 3 years of myositis diagnosis. RESULTS: Cancer was detected in 75 patients, of whom 36 (48%) were positive for anti-TIF1-γ-Ab. In anti-TIF1-γ-Ab(+) patients with CAM, cancers were detected within 1 year of myositis diagnosis in 35 (97%) and before 1 year of myositis diagnosis in 1. All the anti-TIF1-γ-Ab(+) patients with CAM satisfied the dermatomyositis (DM) criteria, including 2 possible DM sine dermatitis cases, and were characterized histologically by the presence of perifascicular atrophy, vacuolated fibers (VFs), and dense C5b-9 deposits on capillaries (dC5b-9). In contrast, 39 anti-TIF1-γ-Ab(-) patients with CAM were classified into various subgroups, and characterized by a higher frequency of necrotizing autoimmune myopathy (NAM). Notably, all 7 patients with CAM classified into the NAM subgroup were anti-TIF1-γ-Ab(-) and exhibited no dC5b-9 or VFs. CONCLUSIONS: CAM includes clinicohistopathologically heterogeneous disease entities. Among CAM entities, anti-TIF1-γ-Ab(+) CAM has characteristically shown a close temporal association with cancer detection and the histopathologic findings of dC5b-9 and VFs, and CAM with NAM is a subset of anti-TIF1-γ-Ab(-) CAM.

Early Stage of Progressive Supranuclear Palsy: A Neuropathological Study of 324 Consecutive Autopsy Cases.

Diagnosing clinical progressive supranuclear palsy (PSP) is challenging. We hypothesize that there are more cases of pathological PSP than have been clinically identified, but its diagnosis is challenging because the initial lesions and progression of PSP have not yet been clarified. The purpose of our study was to clarify the incidence of PSP in consecutive autopsy cases and identify pathological characteristics of early PSP. We investigated 324 consecutive autopsy patients from a general geriatric hospital (age, mean±SD=82.5±8.7 years). Paraffin sections of the midbrain were immunostained with anti 4-repeat tau antibodies (RD4). We selected cases showing RD4-positive neurofibrillary tangles and tufted astrocytes in the midbrain sections. Then, we used anti-phosphorylated tau antibody to immunostain sections from the basal ganglia, subthalamic nucleus, midbrain, pons, medulla, and cerebellum. Of the 324 patients, 35 had RD4-positive structures in the midbrain. From these 35 cases, we excluded those for which autopsies confirmed definite PSP (n=5) and cases of corticobasal degeneration (n=1), Alzheimer's disease (n=11), dementia of grain (n=10), and neurofibrillary tangles predominant forms of senile dementia (n=2), leaving 8 cases. We diagnosed these 8 cases as pure PSP-type tauopathy. Pure PSP-type tauopathy was detected in 2.5% of the consecutive autopsy cases, and this incidence was 1.6 times greater than that of neuropathologically definite PSP. This pure PSP-type tauopathy likely indicates preclinical stages of PSP. Furthermore, the novel neuropathological finding, which we term "preclinical PSP," is unique and has not previously been reported. In order to elucidate the causes and pathological mechanisms of PSP, preclinical PSP should be investigated further.