Decrease in 6R-5,6,7,8-tetrahydrobiopterin content in cerebrospinal fluid of autistic patients

Abstract The levels of pterin compounds in the lumbar cerebrospinal fluid (CSF) of ten neurologically normal and twenty autistic children were measured by two different liquid chromatographic systems, a conventional and a newly developed direct method. Among pterin compounds 7,8-dihydroneopterin (NH 2 ) and 6 R -5,6,7,8-tetrahydrobiopterin ( R -BH 4 ) levels in autistic children were significantly reduced to 66.1 and 41.5%, respectively, of those found in the controls. The autistic children were divided into three subgroups according to their CSF homovanillic acid (HVA) level and age: the group with an elevated HVA level, the younger ( 2 and R -BH 4 levels in the younger group and in the 7,8-dihydropterin (PH 2 ) level in the group with an elevated HVA level. Thus, these results suggest that the endogenous biosynthesis of R -BH 4 in the brain may be reduced in autistic children as compared with that in neurologically normal children.