This grant supported research into the prevalence of cerebral folate deficiency and folate receptor autoantibodies (FRAs) in children with autism spectrum disorders (ASD) and the effect of folinic acid treatment in children with ASD and FRAs. The study measured serum FRAs concentrations in 93 children with ASD. A high prevalence rate (75.3 percent) of FRAs was found in the children participating in the study. Children with FRAs were treated with oral leucovorin calcium (folinic acid), and treatment response was measured and compared with a wait-list control group. Compared with controls, significantly higher improvement ratings were observed in treated children over a mean period of 4 months, in the areas of verbal communication, receptive and expressive language, attention, and stereotypical behavior.