遺伝性失調症の1家系の1剖検例

AN AUTOPSY CASE OF A FAMILY OF HEREDITARY ATAXIA

I．はじめに

　遺伝の関与する運動失調症については，Marieの記載以来，多くの臨床例，剖検例の報告がある。しかし，遺伝関係が濃厚であるかないしは家族内発症が顕著であるか，散発的発生であるかにより，また病変の局在が，脊髄にあるか，脊髄および小脳に及ぶか，小脳にあるかなどにより，各種の分類が試みられている。

　我々は，遺伝関係の濃厚な脊髄小脳型（Menzel型^15））失調症の1家系の1剖検例を経験したので，ここに報告したい。この種の疾患の解明には，臨床像および剖検像を含め，この症例のような大家系の症例の比較検索が，極めて貴重なものであると確信するが，同一家族内の症例が1病院で集約されることは必ずしも容易ではないので，将来集約される機会を希望しつつ，今回1剖検例のみを報告する。

A female, aged 36 at death, complained of cerebel-lar ataxic gait at the age of about 23, which was followed gradually by dysarthria. At the age of 28, the patient showed more clumsiness of gait and speech, and also swallowing disturbance after suffer-ing from common cold. Neurologically she showed exaggeration of deep tendon reflexes, slight muscle atrophy, cerebellar ataxia, Romberg sign, adiado-chokinesis and a slight degree of ptosis.

The same symptoms of the disease have been observed in 5 members of her family (her father already died at the age of 52, her two brothers and two sisters are still alive). Furthermore, looking at her family tree, the same symptoms of the disease have been observed in 22 affected members in four generations of the family. She died after a clinical course of 13 years.

The postmortem examination revealed neuronal atrophy, degeneration and disintegration of Purkinje cells, dentate nuclei, nuclei pontis and olives. Thepontine arms, superficial transverse fibers and resti-form bodies lateral arcuate and association fibers, olivo-cerebellar tracts in the medulla, dorsal tracts of the spinal cord and spino-cerebellar tracts were demyelinated and showed gliosis.

We also observed the degeneration of Betz cells in the cerebral cortex and the nerve cells in the anterior horns and Clarke's columns of the spinal cord. Atrophy of the muscle of extremities was also observed in late stage of this disease. In ad-dition, degeneration and gliosis were also observed in the globus pallidus, thalamic and subthalamic nuclei, red nucleus, substantia nigra, etc.

From the results of the above explanation, we concluded that this case belonged to Menzel type of hereditary ataxia according to Greenfield's clas-sification of spino-cerebellar degeneration.

The outstanding feature of this case is that the inheritance of the disease in this family is so ap-parent that 22 affected members in four generations of such a large family revealed the same symptoms of this disease. As there are few reports of such a large family, we believe that the comparison of other members of this family in future will con-tribute to making clearer this type of disease.

Furthermore, this case is characterized by severe degeneration and decrease of the nerve cells and gliosis in the dentate nuclei and red nuclei. In-tention tremor is inconspicuous in this case, but as it has been observed in other cases of this family, further reseach in future is expected.