Serum neurotrophin concentrations in autism and mental retardation: a pilot study

To evaluate the availability of the serum neurotrophins for the diagnosis of the patients with neurodevelopmental disorder, we measured the serum concentration of brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4) in the patients diagnosed with autism (n=18) and mental retardation (n=20), or healthy controls (n=16), using enzyme-linked immunosorbent assay. There tended to be a higher concentration of serum BDNF found in the autistic group (P<0.05 by analysis of variance (ANOVA)) and the mental retardation group (P<0.001 by ANOVA) compared to the control group. Serum NT-4 concentration tended to be increased in the mental retardation group (P<0.05 by ANOVA). We conclude that measuring the serum concentration of two neurotrophins, BDNF and NT-4, might be helpful to diagnose or classify disorders such as autism or mental retardation.