PSMB9 and type 1 diabetes mellitus: In the catalytic subunit, the rs17587 SNP in the PSMB9 (β1i) gene—resulting in an arginine to histidine substitution at position 60 (Arg60His)—has been identified as a risk factor for T1DM in both Asian and Caucasian populations carrying the HLA DR4-DQB1*0302 haplotype [10,11].