0.8). The strongest evidence of a causal relationship was observed for Neurexophilin And PC-Esterase Domain Family Member 1 (NXPE1) (PIP = 1, testis). Surprisingly, NXPE1 was indicated for the testis (GTEx), whilst it was also highly expressed in the colon (Aguet et al., 2017). The other four genes with strong evidence of a potential causal effect on AN were as follows: WDR6 (PIP = 0.997, DLPFC), PRKAR2A (PIP = 0.814, GTEx artery tibial), PROS1 (PIP = 0.895, GTEx cortex) and the non-coding RNA RP13-238F13.5 (PIP = 0.971, GTEx spinal cord cervical c-1). WDR6 and MST1 were the only genes found to be both conditionally independent with at least moderate finemap evidence of a causal relationship (Table 1). Macrophage Stimulating 1 (MST1) mediates cell division and apoptosis (Wang et al., 2020; Zhang et al., 2019) and is predicted to increase risk of AN (ZTWAS = 4.85, p = 1.2 × 10−6, GTEx Hypothalamus). However, finemapping of the MST1 PWAS indicates evidence of a protective relationship with AN (Zfinemap = −4.63, PIP = 0.457, blood plasma protein). This discordant direction between mRNA and protein requires further investigation to refine its biological salience. The power of finemapping to identify causal genes increases when
