Cerebral folate deficiency (CFD) syndrome is a neurodevelopmental disorder typically caused by folate receptor autoantibodies (FRAs) that interfere with folate transport across the blood–brain barrier. Autism spectrum disorders (ASDs) and improvements in ASD symptoms with
leucovorin (folinic acid) treatment have been reported in some children with CFD. This study suggests that FRAs may be important in ASD and that FRA-positive children with ASD may benefit from leucovorin calcium treatment.