[A case of Creutzfeldt-Jakob disease with markedly elevated ubiquitin concentration in the cerebrospinal fluid].

A 56-year-old woman initially noticed dizziness in October, 1988, and later dementia and gait disturbance developed, associated with myoclonus and periodic synchronous discharge in the electroencephalogram. On the basis of these clinical findings we made a diagnosis of Creutzfeldt-Jakob disease (CJD). Using RIA for ubiquitin (signal peptide of the ATP dependent proteolytic system), we measured the cerebrospinal fluid (CSF) ubiquitin levels. The CSF level of ubiquitin was markedly elevated in this case five months after the initial symptoms (230.0 ng/ml) compared with normal values (14.3 +/- 1.1 ng/ml) and values in patients with senile dementia of Alzheimer type (21.3 +/- 6.1 ng/ml) and vascular dementia (16.6 +/- 6.4 ng/ml). With progression of brain atrophy in this case, CSF levels of ubiquitin rapidly decreased to near the normal values. These findings suggest that CSF ubiquitin concentration reflects the activity of the disease process in CJD, and it may be useful in the diagnosis of CJD.