Guam島筋萎縮性側索硬化症およびParkinsonism-dementiaの神経病理学的研究—24剖検例の観察

NEUROPATHOLOGICAL STUDY OF AMYOTROPHIC LATERAL SCLEROSIS AND PARKINSONISM-DEMENTIA ON GUAM:AN ANALYSIS OF 24 AUTOPSY CASES

　抄録　Guam島Chamorro族の筋萎縮性側索硬化症（ALS）12例，Parkinsonism-dementia （PD）9例，対照3例の剖検脳の検索を行ない，以下の知見を得た。ALS群12例中8例は古典的ALSの病変に加えて特定領域（黒質，青斑核，脳幹網様体，縫線核，中心灰白質，海馬など）に神経原線維変化（NFT）を認めた。NFTを認めず古典的ALSと区別できない症例が2例，NFTを伴う球麻痺を伴う進行性脊髄性筋萎縮症（PMA＋PBP）が1例ある。PD群6例中5例は大脳萎縮，脳室拡大，黒質，青斑核，基底核などの病変と広範なNFTの分布を示す。他の1例はLewy小体を伴う特発性Parkinson病である。PDとALSの合併例と考えられる3例中2例にPDと同様の病変が，1例にPDとALSの両者の病変がある。対照3例中2例にGuam ALSやPDと同様のNFT分布を認める。Chamorro族のNFTは老化現象のみならずこの人種に特有な現象と考えられる。

This is a report on the neuropathological studies of 24 autopsied cases of amyotrophic lateral sclerosis (ALS), Parkinsonism-dementia (PD) and control cases on Guam. All cases were Chamorro people. ALS was clinically diagnosed in 12 cases, and PD in 9 cases.

Neuropathologically, in addition to classical ALS findings, eight out of twelve clinical Guam ALS cases showed widely distributed Alzheimer's neuro-fibrillary tangles (NFT) in the specific regions in the brain stem and the cerebrum. These pathologi-cal findings are compatible with those reported previously in Guam ALS.

Two cases of the clinical Guam ALS group did not show any NFT.

"Progressive Muscular Atrophy associated with Progressive Bulbar Palsy" was pathologically diag-nosed in one case. Only two cases of PMA havebeen reported in Guam previously.

One case in the clinical ALS group showed mild loss of pigmented cells in the substantia nigra with widely distributed NFT extending into the cerebral cortex. Parkinsonian features such as tremor, rigidity and akinesia, dementia, cerebral atrophy and ventricular dilatation were not seen in spite of its long clinical course of 17 years. Therefore, as the pathological diagnosis "Guam ALS with nigral involvement" was considered for this case.

Seven out of 9 cases with clinical PD were pathologically similar to those reported previously ; cerebral atrophy, ventricular dilatation, neuronal depopulation in substantia nigra, locus ceruleus, globus pallidus and subthalamus, associated with more widely distributed NFTs. These 7 cases in-cluding 2 cases with clinical PD/ALS, however, did not disclose the lesions like ALS in the spinal cord anterior horns, hypoglossal nuclei and pyrami-dal tracts. Only one case showed the pathological findings compatible to ALS and PD.

Another case in the PD group manifested Lewy bodies in the regions of substantia innominata, hypothalamus, substantia nigra, locus ceruleus and nucleus Raphe, without NFT and senile plaque. Pigmented cells of substantia nigra and locus ce-ruleus were moderately decreased in number. This case is considered to be the first autopsy report of "Idiopathic Parkinsonism " on Guam.

Two out of 3 control cases revealed NFTs in specific distributions similar to Guam ALS cases. In Guam ALS cases NFTs were often recognized in the oculomotor nucleus and substantia nigra showing no neuronal loss. Two out of 12 clinical ALS cases showed no NFT. The other 3 ALS cases did not reveal NFT in the Sommer's sector of the hippocampus, where NFTs are predominantly located in the aging brain. We might consider NFT is common in Chamorro people, and then the pathological significance of NFT in Guam cases remains to be solved.

Except for the common appearance of NFT, we could find neuropathological evidences of the transi-tion between Guam ALS and PD in only one out of 24 Guam cases.