They include CDR1, a cerebellar degeneration-related protein; LRCH4, a leucine-rich repeat-containing neuronal protein; CACNB2, a subunit of voltage-gated calcium channel and involved in neuronal functions; and FAM123A (AMER2), a member of the gene family involved in neurogenesis (Comai, Boutet, Neirijnck, & Schedl, 2010). Other commonly and most significantly affected genes also encode for proteins critical in cellular functions such as histone (HIST1H4E), transcription regulations (ZGPAT, ERF, and HIVEP3) (Li et al., 2007), and mitochrondrial poly(A) polymerase (PAPD1). A subsequent pathway-targeted analysis of GABAergic genes also revealed common expression changes in the cocaine addicts and alcoholics from our study, such as the downregulation of GABBR1, GABRG2, and GPHN, a gene encoding the associated scaffolding protein gephyrin (Enoch et al., 2012).
