Abstract
To clarify the pathophysiology of learning disability (LD), we measured the urinary levels of 3-methoxy-4-hydroxyphenyl glycol (MHPG), and phenylethylamine (PEA) in urine samples collected in a 24 hour period. Findings were compared with those obtained in age-matched controls and diseased controls including patients with attention deficit-hyperactivity disorder (ADHD), infantile autism, and mental retardation. The mean urinary level of MHPG in LD (n=6) were not significantly different from those in ADHD (n=16), mental retardation (n=4), infantile autism (n=5), and the controls (n=6), while the mean urinary levels of PEA were significantly lower in LD (n=6, 91±17.3μg/mg) and in ADHD (n=5, 65±53.6μg/mg) as compared to age-matched controls (n=3, 340±264.5μg/mg) ANOVA, (p<0.05). PEA is considered to play an important role for the pathogenesis of LD and ADHD.
