This study also confirmed that several variants within GABRA2 were modestly (p<0.05) associated with fast beta EEG in the fronto-central region (Table 4). The association of GABRA2 and beta EEG was initially reported with linkage and association analysis in COGA AD families using the first spatial/spectral component of 11 bipolar electrode pairs and 3 beta frequency bands ranging from 12.5–28 Hz (Porjesz et al., 2002; Edenberg et al., 2004). Subsequently, an association between GABRA2 variants and bipolar beta (13.5–27 Hz) EEG, assessed at fronto-central electrodes, was also reported in a case-control study of AD (Lydall et al., 2011). More recently, Malone et al., (2014) reported an association of GABRA2 and monopolar beta EEG, assessed at the central electrode (i.e., CZ) using GWAS data on a community sample of adolescent twins and their parents (Malone et al., 2014). In the present study, we build upon this prior literature in providing additional support for the association of GABRA2 variants and bipolar fast beta (20–28 Hz) EEG, assessed at fronto-central electrodes, in a family sample enriched for AD.
