RESEARCH: unusual case of sporadic tauopathy

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A clinical and neuropathological study of an unusual case of sporadic

tauopathy. A variant of corticobasal degeneration?

Shinji Ohara, , a, Jun Tsuyuzakia, Takashi Oidea, Hiroyuki Araib, Susumu

Higuchic, Masato Hasegawad and Takeshi Iwatsuboe

a Department of Neurology, National Chushin-Matsumoto Hospital, 811

Kotobuki, Matsumoto 399-0021, Japan

b Department of Geriatrics, Tohoku University School of Medicine, Sendai,

Japan

c Institute of Clinical Research, Kurihama National Hospital, Kanagawa,

Japan

d Department of Molecular Neurology, Tokyo Institute of Psychiatry, Tokyo,

Japan

e Department of Neuropathology and Neuroscience, Graduate School of

Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan

Received 18 April 2002; revised 4 June 2002; accepted 6 June 2002.

Available online 29 August 2002.

Abstract

We report a sporadic case of tauopathy with unusual clinical and

neuropathological features. The patient presented with progressive symmetric

rigid-akinetic parkinsonism and dementia of the subcortical type. Magnetic

resonance imaging of the brain revealed atrophy resembling multiple system

atrophy. The level of cerebrospinal fluid tau protein phosphorylated at

serine 199 was markedly elevated. The autopsy revealed more glial than

neuronal tauopathy, with much heavier involvement of subcortical white

matter and the brainstem than of the cerebral cortex. Analysis of

dephosphorylated tau revealed that hyperphosphorylated four-repeat tau

isoforms were deposited in the brain of the patient. Despite morphological

and biochemical resemblance to a certain form of familial fronto-temporal

dementia, no mutation of the tau gene including exon 10 could be found. Our

findings, taken together with those in previous similar case reports,

indicate that the case represents an atypical form of corticobasal

degeneration or a new variant of sporadic tauopathy.