Bilateral arachnoid cysts of the sylvian region in female siblings with glutaric aciduria type I. Report of two cases.

Two sisters, aged 6 and 2 1/2 years, presented with macrocephaly and delayed motor development and were found on computerized tomography to have bilateral arachnoid cysts of the sylvian region. Cystoperitoneal shunting of the larger cysts resulted in considerable neurological improvement in both children. Subsequent screening of the patients' urine for organic acids showed that the two sisters were suffering from glutaric aciduria type I (GA-I). To the best of the authors' knowledge, this is the first report to provide clear radiological and surgical evidence of the association between GA-I and bilateral arachnoid cysts of the sylvian region. The role of the shunting procedure used in these cases is discussed.