Ichiro Nozaki

Prospective 10-year surveillance of human prion diseases in Japan

We analysed the epidemiological data and clinical features of patients with prion diseases that had been registered by the Creutzfeldt-Jakob Disease Surveillance Committee, Japan, over the past 10 years, since 1999. We obtained information on 1685 Japanese patients suspected as having prion diseases and judged that 1222 patients had prion diseases, consisting of definite (n=180, 14.7%) and probable (n=1029, 84.2%) cases, except for dura mater graft-associated Creutzfeldt-Jakob disease which also included possible cases (n=13, 1.1%). They were classified into 922 (75.5%) with sporadic Creutzfeldt-Jakob disease, 216 (17.7%) with genetic prion diseases, 81 (6.6%) with acquired prion diseases, including 80 cases of dura mater graft-associated Creutzfeldt-Jakob disease and one case of variant Creutzfeldt-Jakob disease, and three cases of unclassified Creutzfeldt-Jakob disease (0.2%). The annual incidence rate of prion disease ranged from 0.65 in 1999 to 1.10 in 2006, with an average of 0.85, similar to European countries. Although methionine homozygosity at codon 129 polymorphism of the prion protein gene was reported to be very common (93%) in the general Japanese population, sporadic Creutzfeldt-Jakob disease in Japan was significantly associated with codon 129 homozygosity (97.5%), as reported in western countries. In sporadic Creutzfeldt-Jakob disease, MM1 type (Parchis classification) is the most common, as in western countries. Among atypical sporadic Creutzfeldt-Jakob disease cases, the MM2 type appeared most common, probably related to the very high proportion of methionine allele in the Japanese population. As for iatrogenic Creutzfeldt-Jakob disease, only dura mater graft-associated Creutzfeldt-Jakob disease cases were reported in Japan and, combined with the data from previous surveillance systems, the total number of dura mater graft-associated Creutzfeldt-Jakob disease was 138, comprising the majority of worldwide dura mater graft-associated Creutzfeldt-Jakob disease patients. Regarding genetic prion diseases, the most common mutation of prion protein gene was V180I (41.2%), followed by P102L (18.1%), E200K (17.1%) and M232R (15.3%), and this distribution was quite different from that in Europe. In particular, V180I and M232R were quite rare mutations worldwide. Patients with V180I or M232R mutations rarely had a family history of prion diseases, indicating that a genetic test for sporadic cases is necessary to distinguish these from sporadic Creutzfeldt-Jakob disease. In conclusion, our prospective 10-year surveillance revealed a frequent occurrence of dura mater graft-associated Creutzfeldt-Jakob disease, and unique phenotypes of sporadic Creutzfeldt-Jakob disease and genetic prion diseases related to the characteristic distribution of prion protein gene mutations and polymorphisms in Japan, compared with those in western countries.

Epidemiology of familial amyloid polyneuropathy in Japan: Identification of a novel endemic focus.

BACKGROUND Familial amyloid polyneuropathy (FAP) is distributed worldwide with several endemic foci including two major foci in Japan. OBJECTIVE To elucidate a nationwide epidemiology of FAP in Japan. DESIGN, SETTING, AND PATIENTS (i) We analyzed the data of FAP patients registered by the Ministry of Health, Labour, and Welfare, Japan, during 2003-2005. (ii) As Ishikawa prefecture was found to be a novel endemic focus, we examined 27 FAP patients in Ishikawa to characterize their clinical and genetic features in comparison with other endemic foci. RESULTS (i) The prevalence of familial amyloidosis in Japan was estimated to be 0.87-1.1 per 1,000,000 persons. Nagano prefecture had the highest prevalence (11-15.5), followed by Kumamoto (10.1-10.3), and then Ishikawa (3.5-4.2). (ii) All the FAP patients in Ishikawa had transthyretin (TTR) type FAP; all the families had a TTR Val30Met mutation except one family with a Leu58Arg mutation. FAP with Val30Met mutation in Ishikawa was characterized by late onset, high penetrance, and moderate autonomic dysfunction. CONCLUSIONS Ishikawa prefecture is the third endemic focus of FAP in Japan. FAP with TTR Val30Met mutation in Japan can be classified to (i) early-onset and endemic (Nagano and Kumamoto), (ii) late-onset and endemic (Ishikawa), and (iii) late-onset and non-endemic types.

Dura mater graft-associated Creutzfeldt-Jakob disease in Japan: Clinicopathological and molecular characterization of the two distinct subtypes

Up to February 2008, a total of 132 patients with dura mater graft‐associated Creutzfeldt‐Jakob disease (dCJD) have been identified in Japan, accounting for a majority of the worlds patients with dCJD. The patients received dura mater grafts from 1978 to 1993. Lyodura® (B. Braun, Melsungen, Germany) was used for all the patients in whom the brand name of the dura mater could be identified. After the incubation period of 1 to 25 years (mean, 11.8 years), CJD appeared from 1985 through to 2006. We analyzed clinical, pathological, and molecular features in 74 patients with dCJD who had been prospectively registered by the CJD Surveillance Committee. The cases of dCJD could be classified into two distinct clinicopathological phenotypes: a non‐plaque type, showing typical features identical with those of classic CJD, and a plaque type, characterized by atypical features, including slow progression, lack of or late occurrence of periodic sharp wave complexes on EEG, and plaque formation in the brain. The plaque type accounted for one‐third of the pathologically confirmed or clinically diagnosed cases of dCJD. The non‐plaque type was associated with methionine homozygosity at codon 129 (129M/M) of the PrP gene in all patients, except for in one patient with the 129M/valine (V) genotype and type 1 protease‐resistant PrP (PrPres), whereas the plaque type was always associated with the 129M/M genotype and the intermediate type between types 1 and 2 of PrPres in all cases. Thus, the clinicopathological and molecular features of the plaque type are distinct from those of the non‐plaque type, suggesting contamination of the dura mater grafts with different prion strains.

The risk of iatrogenic Creutzfeldt‐Jakob disease through medical and surgical procedures

There have been more than 400 patients who contracted Creutzfeldt‐Jakob disease (CJD) via a medical procedure, that is, through the use of neurosurgical instruments, intracerebral electroencephalographic electrodes (EEG), human pituitary hormone, dura mater grafts, corneal transplant, and blood transfusion. The number of new patients with iatrogenic CJD has decreased; however, cases of variant CJD that was transmitted via blood transfusion have been reported since 2004. Clearly, iatrogenic transmission of CJD remains a serious problem. Recently, we investigated medical procedures (any surgery, neurosurgery, ophthalmic surgery, and blood transfusion) performed on patients registered by the CJD Surveillance Committee in Japan during a recent 9‐year period. In a case‐control study comprising 753 sporadic CJD (sCJD) patients and 210 control subjects, we found no evidence that prion disease was transmitted via the investigated medical procedures before onset of sCJD. In a review of previously reported case‐control studies, blood transfusion was never shown to be a significant risk factor for CJD; our study yielded the same result. Some case‐control studies reported that surgery was a significant risk factor for sCJD. However, when surgical procedures were categorized by type of surgery, the results were conflicting, which suggests that there is little possibility of prion transmission via surgical procedures. In our study, 4.5% of sCJD patients underwent surgery after onset of sCJD, including neurosurgeries in 0.8% and ophthalmic surgeries in 1.9%. The fact that some patients underwent surgery, including neurosurgery, even after the onset of sCJD indicates that we cannot exclude the possibility of prion transmission via medical procedures. We must remain vigilant against prion diseases to reduce the risk of iatrogenesis.

Fulminant devic disease successfully treated by lymphocytapheresis

Devic disease is a demyelinating disease characterised by acute optic neuritis and transverse myelitis. Although there are differences in the pathogenesis of Devic disease and multiple sclerosis, the treatment for Devic disease is the same as that for multiple sclerosis. We report a patient with Devic disease who was resistant to high-dose intravenous methylprednisolone and intravenous immunoglobulin (Ig) treatments, but was effectively treated with lymphocytapheresis (LCP). The profiles of cytokines during the clinical course are discussed. In August 2001, a 27-year-old woman developed acute loss of vision and sensory disturbance in both lower extremities after coughing. The next morning (day 2), she was totally blind and was admitted to our hospital. Neurological examination showed total blindness, papilloedema, moderate muscle weakness of the hip and thigh muscles, positive pathological reflexes of the limbs, hyper-reflexia and sensory loss below the T4–5 level. Loss of vesicorectal function and perspiration below the chest were also observed. Laboratory examination disclosed a normal C-reactive protein level, positive antinuclear (titre 1/160) and antithyroglobulin antibodies (0.8 U/ml (normal range <0.3)) in serum, normal CD4:CD8 ratio (0.90 (normal range 0.69−1.74)) and an increased percentage of CD8 T cells (45% of total T cells (normal range 12−30%)). Anti-neutrophil cytoplasmic antibodies, anti-phospholipid antibodies and rheumatoid factor were …

Medical procedures and risk for sporadic Creutzfeldt-Jakob disease, Japan, 1999-2008.

Surgery or blood transfusion had little effect on the incidence of sCJD.

Insight into the frequent occurrence of dura mater graft-associated Creutzfeldt-Jakob disease in Japan

Objective More than 60% of patients worldwide with Creutzfeldt-Jakob disease (CJD) associated with dura mater graft (dCJD) have been diagnosed in Japan. The remarkable frequency of dura mater grafts in Japan may possibly contribute to the elevated incidence of dCJD, but reasons for the disproportionate use of this procedure in Japan remain unclear. We investigated differences between dCJD patients in Japan and those elsewhere to help explain the more frequent use of cadaveric dura mater and the high incidence of dCJD in Japan. Methods We obtained data on dCJD patients in Japan from the Japanese national CJD surveillance programme and on dCJD patients in other countries from the extant literature. We compared the demographic, clinical and pathological features of dCJD patients in Japan with those from other countries. Results Data were obtained for 142 dCJD patients in Japan and 53 dCJD patients elsewhere. The medical conditions preceding dura mater graft transplantation were significantly different between Japan and other countries (p<0.001); in Japan, there were more cases of cerebrovascular disease and hemifacial spasm or trigeminal neuralgia. Patients with dCJD in Japan received dura mater graft more often for non-life-threatening conditions, such as meningioma, hemifacial spasm and trigeminal neuralgia, than in other countries. Conclusions Differences in the medical conditions precipitating dura mater graft may contribute to the frequent use of cadaveric dura mater and the higher incidence of dCJD in Japan.

The MM2-cortical form of sporadic Creutzfeldt–Jakob disease presenting with visual disturbance

A subclass of sporadic Creutzfeldt–Jakob disease (sCJD) characterized by onset with visual symptoms (Heidenhain variant) has been reported to belong to the MM1 or MV1 type according to Parchis classification. The authors report a 65-year-old woman with MM2-cortical sCJD with slowly progressive visual disturbance as the initial symptom. Diffusion-weighted MRIs revealed hyperintensity in both occipital cortices at an early stage.

Clinical features of genetic Creutzfeldt-Jakob disease with V180I mutation in the prion protein gene

Objectives Genetic Creutzfeldt-Jakob disease (CJD) due to V180I mutation in the prion protein gene (PRNP) is of great interest because of the differences from sporadic CJD and other genetic prion diseases in terms of clinical features, as well as pathological and biochemical findings. However, few systematic observations about the clinical features in patients with this unique mutation have been published. Therefore, the goal of this study was to relate this mutation to other forms of CJD from a clinical perspective. Design We analysed clinical symptoms, prion protein genetics, biomarkers in cerebrospinal fluid (CSF) and MRI of patients. Participants 186 Japanese patients with the V180I mutation in PRNP. Results Our results indicate that the V180I mutation caused CJD at an older age, with a slower progression and a lower possibility of developing myoclonus, cerebellar, pyramidal signs and visual disturbance compared with classical sporadic CJD with methionine homozygosity at codon 129 of PRNP. Cognitive impairment was the major symptom. Diffuse hyperintensity of the cerebral cortex in diffusion-weighted MRI might be helpful for diagnosis. Owing to the low positivity of PrPSc in the CSF, genetic analysis was often required for a differential diagnosis from slowly progressive dementia. Conclusions We conclude that the V180I mutation in PRNP produces a late-developing and slow-developing, less severe form of CJD, whose lesions are uniquely distributed compared with sporadic and other genetic forms of CJD.

Relationships between Clinicopathological Features and Cerebrospinal Fluid Biomarkers in Japanese Patients with Genetic Prion Diseases

A national system for surveillance of prion diseases (PrDs) was established in Japan in April 1999. Here, we analyzed the relationships among prion protein gene (PRNP) mutations and the clinical features, cerebrospinal fluid (CSF) markers, and pathological characteristics of the major genotypes of genetic PrDs (gPrDs). We retrospectively analyzed age at onset and disease duration; the concentrations and incidences of 14-3-3 protein, tau protein, and abnormal prion protein (PrPSc) in the CSF of 309 gPrD patients with P102L, P105L, E200K, V180I, or M232R mutations; and brain pathology in 32 autopsied patients. Three clinical phenotypes were seen: rapidly progressive Creutzfeldt-Jakob disease (CJD), which included 100% of E200K cases, 70% of M232R, and 21% of P102L; slowly progressive CJD, which included 100% of V180I and 30% of M232R; and Gerstmann-Sträussler-Scheinker disease, which included 100% of P105L and 79% of P102L. PrPSc was detected in the CSF of more than 80% of patients with E200K, M232R, or P102L mutations but in only 39% of patients with V180I. V180I was accompanied by weak PrP immunoreactivity in the brain. Patients negative for PrPSc in the CSF were older at disease onset than positive patients. Patients with mutations associated with high 14-3-3 protein levels in the CSF typically had synaptic deposition of PrP in the brain and a rapid course of disease. The presence of small PrP protein fragments in brain homogenates was not correlated with other clinicopathological features. Positivity for PrPSc in the CSF may reflect the pathological process before or at disease onset, or abnormality in the secretion or metabolism of PrPSc. The amount of 14-3-3 protein in the CSF likely indicates the severity of the pathological process and accompanying neuronal damage. These characteristic features of the CSF in cases of gPrD will likely facilitate accurate diagnosis and clinicopathological study of the various disease subtypes.