Our linkage signal at the 15q13.3-q14 region (1-LOD interval 22–28 cM) is about 10 cM (or 6–7 Mb) telomeric to the 15q11-q13 region, which has been a focus of many association studies due to the interests in the γ-aminobutyric acid receptor α, β, and γ subunit genes in this region (48–50). Most interestingly, markers at the 15q13.3-q14 region have also been linked with an endophenotype of schizophrenia, P50 sensory gating disorder (51), and with schizophrenia itself (52,53). The most studied candidate gene in this region is α7-nicotinic cholinergic receptor (CHRNA7), which controls the excitability of local neuronal circuitries in the human cerebral cortex (54). In this study, the flanking SNPs for CHRNA7 (at 22.6–22.9 cM) were rs953325 at 22.4 cM (LOD score = 3.17, p = .00007) and the most significant rs1454985 at 24.8 cM (LOD score = 4.01, p = .00001).
