Abstract
As inborn errors of folic acid metabolism, formiminotransferase deficiency and N^5-methyltetrahydrofolate transferase deficiency were reported. Clinical features common to both syndromes were mental retardation, abnormalities in EEG and PEG which were considered to be resulted from an impaired purine biosynthesis of the growing brain due to metabolic error of folic acid. That folic acid deficiency in early infancy caused a delay in maturation patterns of the EEG basic waves was demonstrated by experimental and clinical studies.
