Prevalence of spinocerebellar degenerations in the Hokuriku district in Japan.

BACKGROUND: The prevalence of disease subtypes of spinocerebellar degenerations (SCDs) varies between countries, and even between areas within a country. We report unprecedented epidemiologic data on SCDs in the Hokuriku district, which is located in the central, western part of Japan. METHODS: Clinical and genetic data on SCD patients were obtained via questionnaires distributed to all the departments of neurology, psychiatry and internal medicine in the Hokuriku district (n = 418). RESULTS: Among the SCD patients, autosomal dominant cerebellar ataxias (ADCAs) were noted in 40.4%, multiple system atrophy in 24.7%, cortical cerebellar atrophy in 13.3% and autosomal recessive cerebellar ataxia in 0.3%. Genetically confirmed ADCA patients included those with Machado-Joseph disease (MJD)/spinocerebellar ataxia type 3 (SCA3; 63.3%), SCA6 (20.0%), ADCA linked to chromosome 16q22.1 (10.0%), dentatorubral pallidoluysian atrophy (4.4%), SCA1 (1.1%) and SCA2 (1.1%). MJD/SCA3 was highly prevalent in the Toyama prefecture of the Hokuriku district, accounting for 90% of genetically confirmed ADCAs by birthplace; MJD/SCA3 patients were concentrated in the Gosei area, the western part of the Toyama prefecture, giving an estimated prevalence of 19.1 per 100,000 inhabitants. CONCLUSIONS: The Hokuriku district, especially the Gosei area of Toyama, had a surprisingly high relative frequency and prevalence of MJD/SCA3, which is comparable to that in the Azores, Portugal.

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.

B-cell neurolymphomatosis confined to the peripheral nervous system.

Patients with neurolymphomatosis show lymphoma cells within the peripheral nerves, nerve root/plexus, or cranial nerves. However, most neurolymphomatosis patients show lymphomatous infiltration not only in the peripheral nervous system (PNS), but also in the meninges, Virchow-Robin space, and brain parenchyma. Here, we report a 74-year-old woman with diffuse large B-cell lymphoma presenting with motor-sensory-autonomic polyneuropathy and multiple cranial neuropathies. A diagnosis of neurolymphomatosis was made by sural nerve biopsy. Postmortem examination indicated that lymphoma cell infiltration in the nervous system was confined to the PNS with no involvement of the central nervous system, including the meninges. This was a very rare case of B-cell neurolymphomatosis with lymphomatous infiltration confined to the PNS, suggesting specific affinity of the lymphoma cells for the PNS in this patient.