Proteins are central to almost all cellular processes, and dysregulation of 
expression and function is associated with a range of disorders. A number of 
studies in human have recently shown that genetic factors significantly 
contribute gene expression variation. In contrast, very little is known about 
the genetic basis of variation in protein abundance in man. Here, we assayed the 
abundance levels of proteins in plasma from 96 elderly Europeans using a new 
aptamer-based proteomic technology and performed genome-wide local (cis-) 
regulatory association analysis to identify protein quantitative trait loci 
(pQTL). We detected robust cis-associations for 60 proteins at a false discovery 
rate of 5%. The most highly significant single nucleotide polymorphism detected 
was rs7021589 (false discovery rate, 2.5 × 10(-12)), mapped within the gene 
coding sequence of Tenascin C (TNC). Importantly, we identified evidence of 
cis-regulatory variation for 20 previously disease-associated genes encoding 
protein, including variants with strong evidence of disease association show 
significant association with protein abundance levels. These results demonstrate 
that common genetic variants contribute to the differences in protein abundance 
levels in human plasma. Identification of pQTLs will significantly enhance our 
ability to discover and comprehend the biological and functional consequences of 
loci identified from genome-wide association study of complex traits. This is 
the first large-scale genetic association study of proteins in plasma measured 
using a novel, highly multiplexed slow off-rate modified aptamer (SOMAmer) 
proteomic platform.