Decreased 24-hour urinary MHPG in childhood autism.

: The authors compared a group of boys with childhood autism and a group of normal boys of similar age and found a decrease in urinary 3-methoxy-4-hydroxyphenethylene glycol (MHPG) in the autistic group. They hypothesize that autistic children might have an alteration in central and peripheral noradrenergic function, which might be related to impaired regulation of attention, arousal, and anxiety.