Analysis of urinary pterins in autism.

The pterins, neopterin and biopterin, occur normally in body lluids including urine. It has been known for some time that increased production and release of neopterin and 7,sdihydroneopterin accompanies immune activation of macrophages both in vilro and in vivo [ 1.21. Interferon gamma and tuniour necrosis factor alpha are the key cytokines which lead to this increase in neopterin levels [2] by inducing exclusively the activity of GTP cyclohydrolase. The determination of neopterin in body fluids of groups of patients with diverse diseases involving cellular immunity has provided a consistent view that this marker i s able to follow the undulating course of disease severity and hence aid in diagnostic and therapeutic decisions [2]. In most tissues. G'IP cyclohydrolase is the first step o f a biosynthetic pathway that leads ultimately to the formation of BH, which acts as a cofactor for various reactions including NO synthetase and the aromatic amino acid hydroxylases and is therefore required for the biosynthesis of some neurotransmitters. Any disruption of BH, metabolism can lead to neurological problems.