We tested whether eQTLs for CHRNA5 expression found in human brain are also present in lymphoblastoid cells. We measured CHRNA5 total mRNA expression levels in 60 lymphoblastoid cell lines from European Americans and 60 lymphoblastoid cell lines from African Americans and examined the effect of rs880395 and rs3841324 on expression. In cells from European Americans, both rs880395 (p = 1.02×10−3) and rs3841324 (p = 6.0×10−4) were significantly associated with variability of CHRNA5 mRNA expression. However, the effect is much weaker and is in the opposite direction to the effect detected in frontal cortex. The minor alleles of rs880395 and rs3841324 are associated with increased mRNA expression of CHRNA5 in human frontal cortex (Figure 1) but they are associated with decreased mRNA expression of CHRNA5 in lymphoblastoid cells (Figure S2a). In cells from African Americans, no significant effect of rs880395 or rs3841324 on CHRNA5 mRNA expression was observed (Figure S2b).
