For four of the top six CpGs previously identified in a meta-EWAS of type 2 diabetes that had bidirectional 2SMR data (CpGs in TXNIP, HDAC4, SYNM and ABCG1), the observational and causal effects were consistent only at HDAC4 (cg00144180). Here, HDAC4 is linked to type 2 diabetes mellitus.