In what we believe is the first GWAS of fast beta EEG in families of AA, we report a genome-wide significant signal in an intergenic region on 3q26. The most significant SNP, rs11720469, was negatively associated with fast beta EEG (β: − 0.124). Interestingly, this same intergenic region has been previously implicated in a sub-threshold (that is, approaching genome-wide significant) association and gene-based association (C3orf57) in the report by Hodgkinson et al. of monopolar beta (13–30 Hz) EEG in 322 Native Americans.27 Note that, although the present study focused on fast beta (20–28 Hz), post hoc analyses indicated that the 3q26 signal is also observed at a genome-wide level for mid-beta (16–20 Hz) and at a sub-threshold level for low beta (12–16 Hz). We present Manhattan plots for the three beta frequency sub-bands in Supplementary Figure S2: (a) 12–16 Hz, (b) 16–20 Hz, and (c) 20–28, for comparison.
