Relationship of apolipoprotein E and age at onset to Parkinson disease neuropathology.

Previous studies investigating the association between apolipoprotein E (APOE) genotypes and Parkinson disease (PD) have yielded conflicting results, and only a few have addressed APOE as a possible determinant of PD pathology. Therefore, we aimed to evaluate the relationship between APOE and PD as well as APOE and PD pathology. We studied 108 pathologically verified patients with PD and 108 controls pair-matched for age and gender. Allele frequencies of APOE differed between patients with PD and controls (p = 0.02). The frequency of epsilon4 allele increased (p = 0.01), whereas that of epsilon3 allele decreased with advancing PD pathology (p = 0.002). Only age of PD onset was an independent predictor for the rate of progression of PD pathology in which late-onset patients appeared to reach end point PD pathology more rapidly than early-onset patients (p = 0.001). In conclusion, our findings suggest that APOE may express its effect on the risk of PD by modifying the occurrence of PD pathology, but age of PD onset seems to be the principal determinant of the progression rate of PD pathology.

Familial cortical tremor with epilepsy and cerebellar pathological findings.

The clinical and neuropathological findings in a patient with familial cortical tremor with epilepsy (FCTE) are described. Clinically, the patient showed cortical myoclonus, tremor, and generalized seizures. Pathological investigation showed cerebellar degeneration and somal sprouting and loss of dendritic tree in Purkinje cells. Striking similarities were found in diseases caused by channelopathies such as spinocerebellar ataxia subtype 6.

Staging of brain pathology related to sporadic Parkinson's disease.

Sporadic Parkinson's disease involves multiple neuronal systems and results from changes developing in a few susceptible types of nerve cells. Essential for neuropathological diagnosis are alpha-synuclein-immunopositive Lewy neurites and Lewy bodies. The pathological process targets specific induction sites: lesions initially occur in the dorsal motor nucleus of the glossopharyngeal and vagal nerves and anterior olfactory nucleus. Thereafter, less vulnerable nuclear grays and cortical areas gradually become affected. The disease process in the brain stem pursues an ascending course with little interindividual variation. The pathology in the anterior olfactory nucleus makes fewer incursions into related areas than that developing in the brain stem. Cortical involvement ensues, beginning with the anteromedial temporal mesocortex. From there, the neocortex succumbs, commencing with high order sensory association and prefrontal areas. First order sensory association/premotor areas and primary sensory/motor fields then follow suit. This study traces the course of the pathology in incidental and symptomatic Parkinson cases proposing a staging procedure based upon the readily recognizable topographical extent of the lesions.

Argyrophilic grain disease and Alzheimer's disease are distinguished by their different distribution of tau protein isoforms.

Prominent neuronal and glial tau filamentous inclusions are hallmarks of neurodegenerative tauopathies, among them Alzheimer's disease (AD), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), Pick's disease (PiD), and argyrophilic grain disease (AgD). AgD is a late onset dementia in which pathologically aggregated tau proteins are found in limbic structures in the shape of distinct argyrophilic grains and coiled bodies. Until now tau protein deposits in AgD have not been assessed biochemically. We therefore decided to investigate the electrophoretic profile of pathological tau protein as well as the tau protein isoform composition of filamentous inclusions in AgD cases. A distinct pathological tau doublet at 64 and 69 kDa and a minor 74-kDa band was obtained in two AgD cases with only very mild concomitant AD pathology (Braak stage I), while in two AgD cases with moderate AD pathology (Braak stage II and III, respectively), an additional minor band at 60 kDa was detected. Thus, the pathological tau profile (PTP) in pure AgD cases differs from both the PTPs in AD (tau triplet at 60, 64 and 69 kDa, minor band at 74 kDa) and PiD (major tau doublet at 60 and 64 kDa, minor band at 69 kDa) but not from those in PSP and CBD. Using a two-dimensional gel electrophoresis approach anti-exon 10 antiserum strongly stained the AgD doublet and the minor 74-kDa band, while anti-exon 2 and 3 antisera only faintly stained the 69- and the minor 74-kDa component, thus suggesting that pathological tau aggregates in AgD are mainly made of four-repeat (4R) tau isoforms. Furthermore, in contrast to earlier immunohistochemical studies, we now show biochemically that Ser262 indeed is phosphorylated in the PTP of AgD. Finally, expression of normal tau protein was not found to be altered in AgD. Altogether, our results demonstrate that AgD is characterized by a major tau doublet that is distinct from AD and PiD. AgD, however, shares the pathological tau doublet (64 and 69 kDa) as well as the predominance of 4R tau isoforms with CBD and PSP.