The loci identified by GWAS contain large numbers of variants, not all of which are known to be functional or related to the phenotype analyzed. High‐throughput reporter assays (HTRAs) can systematically identify which SNPs have regulatory activity and which may differ between different cell types by comparing the effects of both alleles for each SNP on expression of reporter genes in relevant cell types. A novel technique, PASSPORT‐seq, 19 , 20 allows functional testing of multiple 3′UTR variants in parallel (Figure 2). Initially, PASSPORT‐seq was used to analyze all variants in the 3′UTR of 88 genes that showed expression differences in four brain regions between control and AUD participants. 20 Results demonstrated biased allelic expression of 53 SNPs in one neuroblastoma cell line (SH‐SY5Y cells) and 130 in another (SK‐N‐BE (2) cells). Among these, the direction of allele bias in both SH‐SY5Y and SK‐N‐BE (2) cell lines was the same in 25 loci. Eighteen of these 25 SNPs were in eQTLs as defined in the GTEx database, 21 7 lay within binding sites of ELAVL1 (ELAV‐like RNA binding protein 1),
