For mean platelet volume (MPV) we observed that MPV SNPs rs12485738 on 3p26 and rs11602954 on 11p15 affect several transcripts in trans. These two SNPs converge on GP9, F13A1, C19orf33, SAMD14, VCL and GNG11. As GP9 and F13A1 are known blood coagulation genes, C19orf33 is a potential candidate gene, involved in coagulation as well. This is substantiated by strong co-expression between GP9 and C19orf33 within peripheral blood (Pearson r = 0.45, p = 7.0×10−63) and the fact these SNPs independently also affect various other blood coagulation genes in trans (including CD151, GP1BB, ITGA2B, MMRN1, THBS1 and VWF, Figure 4). Many of these are specific to megakaryocytes that are platelet precursor cells [43]. As expected, the Gene Ontology term ‘blood coagulation’ is strongly overrepresented among all these trans-genes, Fisher's exact p = 1.0×10−10.
