CLINICAL-FEATURES OF PROBABLE MOYAMOYA-DISEASE IN JAPAN

To clarify the current clinical features of probable Moyamoya disease in Japan, 180 cases were analyzed based on the cases collected by the Research Committee on Spontaneous Occlusion of the Circle of Willis of the Ministry of Health and Welfare, Japan. Although the age distribut ion patterns of probable Moyamoya disease showed two peaks similar to that of definite cases, the pattern shifted to the right thus indicati ng a reversed children versus adult ratio. The female/male ratio was 1 .65, which was not significantly different from that observed in defin ite cases. The family occurrence rate was 6.7%. The incidence of cereb ral infarction and bleeding in probable cases was higher than that in definite cases. The incidence of hemorrhage was higher in females than in males. Angiographically probable cases were at earlier stages in c omparison to definite cases. The rebuild-up phenomenon in electroencep halograms was less detectable than in definite cases. Surgical procedu res were performed in 63.3% of all cases and approximately 81% of them underwent bypass surgery. Single encephalo-duro-arterio-synangiosis, direct bypass and combined bypass procedures were performed in 35, 40 and 25% of all surgical cases, respectively. Although the incidence of bleeding was higher in the probable cases, the outcomes of the patien ts were similar to that of the definite cases except for mortality. Ap proximately 7% of the probable cases developed into definite type with in an average 6.6 year follow-up period. The majority of probable Moya moya disease cases thus seems to have somewhat different clinical char acteristics from the definite disease cases. (C) 1997 Elsevier Science B.V.