a panel of 74 neural patterning genes used by other investigators (Brennand et al., 2014) to compare developmental characteristics of iPSC-derived neural cultures (Supplemental Table 1). These results suggest that the two clusters had a similar degree of neuronal maturation and forebrain lineage features. Interestingly, there was no difference in expression of the two genes directly adjacent to the chr4p12 GABAA cluster, GNPDA2 and COMMD8 (Figure 4B 1 and 6), located ~1.3 Mb and 25 kb from GABRG1 and GABRB1, respectively (Figure 4A). Taken together, these findings strongly suggest that genetic variation in the GABRA2 AD-associated haplotype block influences developmental regulation of the entire cluster of chr4p12 GABAA subunit genes in this iPSC-derived neural culture model. Further, our findings were replicable across multiple neural differentiations of individual iPSC lines, as there were no differences observed in GABAA expression patterns from the iPSC-derived neural cells differentiated on different dates.
