Macrocytosis in Down's syndrome and during long-term anticonvulsant therapy

SYNOPSIS In a group of non-anaemic mentally retarded patients a significant increase in mean red cell volume has been demonstrated in epileptic patients being treated with anti-convulsants. The possible sites of interference of anticonvulsants with folate activity in the body, and problems associated with folic acid supplements during anticonvulsant therapy, are discussed. During the survey it was confirmed that the mean red cell volume is abnormally increased in many cases of Down's syndrome. Long-term anticonvulsant therapy has been shown to be associated with correctable folate deficiency, erythrocyte macrocytosis, and frank megaloblastic anaemia in some cases (Dahlke an