Brain-derived neurotrophic factor and autism: maternal and infant peripheral blood levels in the Early Markers for Autism (EMA) Study.

To investigate levels of brain-derived neurotrophic factor (BDNF) in mid-pregnancy and neonatal blood specimens as early biologic markers for autism, we conducted a population-based case-control study nested within the cohort of infants born from July 2000 to September 2001 to women who participated in the prenatal screening program in Orange County, CA. Cases (n=84) were all children receiving services for autism at the Regional Center of Orange County. Two comparison groups from the same study population were included: children with mental retardation or developmental delay (n=49) receiving services at the same regional center, and children not receiving services for developmental disabilities, randomly sampled from the California birth certificate files (n=159), and frequency matched to autism cases on sex, birth year, and birth month. BDNF concentrations were measured in archived mid-pregnancy and neonatal blood specimens drawn during routine prenatal and newborn screening using a highly sensitive bead-based assay (Luminex, Biosource Human BDNF Antibody Bead Kit, Invitrogen-Biosource, Carlsbad, CA). The concentration of BDNF in maternal mid-pregnancy and neonatal specimens was similar across all three study groups. These data do not support previous findings of an association between BDNF and autism and suggest that the concentration of BDNF during critical periods of early neurodevelopment is not likely to be a useful biomarker for autism susceptibility.