PeQTL > 1.6 × 10−3 (equivalent to χ2 < 10) to avoid weak instrumental variables according to the original paper [22]. The null hypothesis of the HEIDI test was that there was a single causal variant which meant that there was no heterogeneity in the bXY values. A p value threshold of PHEIDI > 0.05 was conservative for a gene having “pleiotropy” effects (no heterogeneity) [22].
