DECREASE IN 6R-5,6,7,8-TETRAHYDROBIOPTERIN CONTENT IN CEREBROSPINAL-FLUID OF AUTISTIC PATIENTS

The levels of pterin compounds in the lumbar cerebrospinal fluid (CSF) of ten neurologically normal and twenty autistic children were measur ed by two different liquid chromatographic systems, a conventional and a newly developed direct method. Among pterin compounds 7,8-dihydrone opterin (NH2) and 6R-5,6,7,8-tetrahydrobiopterin (R-BH4) levels in aut istic children were significantly reduced to 66.1 and 41.5%, respectiv ely, of those found in the controls. The autistic children were divide d into three subgroups according to their CSF homovanillic acid (HVA) level and age: the group with an elevated HVA level, the younger (<7 y ear old) group with a normal HVA level. and the older (>7 year old) gr oup with a normal HVA level. In comparison, the further reduction was observed in NH2 and R-BH4 levels in the younger group and in the 7,8-d ihydropterin (PH2) level in the group with an elevated HVA level. Thus , these results suggest that the endogenous biosynthesis of R-BH4 in t he brain may be reduced in autistic children as compared with that in neurologically normal children.