長崎県島原地方の網膜芽細胞腫の発生頻度と全国調査との比較

Incidence of retinoblastoma in Shimabara district in Nagasaki Prefecture compared with the nationwide one

　過去22年間の調査で，長崎県での網膜細胞芽腫の発症頻度は，両眼性では49,564人の出生に1例，片眼性では16,035人の出生に1例であった。これに対し，島原地方では，10,330人の出生に1例と高率であった。島原地方の史実から，関係の深い兵庫県丹波と但馬地方での発症率を調査した。丹波では10,570対1，但馬では10,410対1であり，3地方で発症率は酷似していた。

A total of 34 patients with retinoblastoma was detected in Nagasaki Prefecture during a 22-year-period ending 1986.

Retinobastoma was unilateral in 23 and bilateral in 11.

Its incidence was 1/16,035 births for unilateral cases and 1/49,564 for bilateral ones. In Shimabara Disctrict in Nagasaki Prefecture, the overall inci-dence was peculiarly high at 1/10,330 births. Histor-ically, almost all the native inhabitants in Shimabara District were killed during a religious war in 1637, so that the current inhabitants are descendants of immigrants from Hyogo, Aichi and Shizuoka Prefectures in central Japan. We could ascertain the incidence of retinoblastoma in Tamba and Tajima districts in Hyogo Prefecuture to be 1/ 10,570 and 1/10,410 respectively.

The close similarity in the incidence of retinob-lastoma in these three districts appeared to be due to common genetic features.