genes were grouped by their biological functions, cellular locations, and possible interactions of their encoded proteins. The gene networks were visualised in a connectivity diagram. Using the same strategy, the top meta-analyses SNPs located in or close to genes were summarized in a connectivity diagram (Figure 1). Inspection of those top-ranked SNPs, in the light of potential gene networks involved in AD or ND, yielded a number of interesting findings. One group consisted of ion-channels, including several potassium voltage-gated ion channels, calcium ion-channels and several other types of ion-channels. KCNMA1 encodes a potassium large conductance calcium-activated channel. It has been postulated as a protein targeted by Lobeline which is a smoking cessation aid (Hu & Agarwal, 2009). In addition, chronic smoking has been shown to down-regulate KCNMA1 protein synthesis and mRNA expression in bronchial and bronchiolar smooth muscles in rats (Ye et al., 2004). KCNMA1 also affects the level of response to alcohol in humans (Schuckit et al., 2005) and C. elegans (Davies et al., 2003). Because KCNMA1 has been implicated in nicotine- and alcohol-related disorders in other studies (Davies et al., 2003; Hu & Agarwal, 2009; Schuckit et al., 2005; Ye et al., 2004) and several potassium voltage-gated ion
