eQTLs are genomic loci that contribute to variation in expression levels of mRNAs (wikipedia).
There is data out there that shows that ~60% of the time, the amount of mRNA in a cell is directly proportional to the level of protein coded by that mRNA.
It means that even if the abundance of mRNA is high, we cannot be sure that the abundance of protein is high as well. Why do we still need eQTL if we cannot derive abundance of protein from mRNA transcripts? In the end, the abundance of protein influences the disease rather than the abundance of a transcript.
Does a pQTL implement the idea of a relationship between a genetic variance and the abundance of a protein? I do not understand how a genetic variance can influence the protein level. I assume it is related with a post-transcriptional modification but how?