In this large study of over 20,000 AAs we densely fine mapped the entire FTO gene and adjacent RPGRIP1L gene, spanning a total region of almost 650 kb. We observed significant associations for variants in the known locus in intron 1 of FTO. Due to reduced correlation in AA compared with EA with the most significant SNPs, we were able to substantially reduce the number of functional candidates. Six SNPs were located within candidate intronic regulatory elements, including rs1421085, for which we predicted allele-specific binding affinity for the transcription factor CUX1. Because we did not focus solely on the known FTO intron 1 region, we were able to comprehensively investigate the region; however, this approach revealed no evidence for a second independent signal in AA.
