Human fetuin, also known as α-2-HS glycoprotein, is an abundant glycoprotein circulating in human plasma. AHSG is the gene symbol responsible for coding the fetuin protein. A frequent polymorphism of AHSG results in two alleles, AHSG*1 and AHSG*2, which producing three genotypes (AHSG*1, AHSG*2, and heterozygous AHSG1/2). The backbone amino acid sequences of fetuin coded by AHSG*1 and AHSG*2 genes differ from each other in two amino acids including one O-glycosylation site (position 256). We aim to describe human’s individual fetuin proteoform profiles directly isolated from serum of healthy and septic people, focusing on potential glycoproteogenomics correlations, e.g. how gene polymorphisms may affect glycosylation.