Objective: To investigate the relationship of polymorphism of large multifunctional protease (LMP) 2 genes to insulin-dependent diabetes mellitus (IDDM) and DR3 gene.
Methods: The polymorphism of LMP2 genes was identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 68 IDDM patients and 71 healthy controls. IDDM patients and healthy controls were respectively divided into 2 groups according to DR3 genotyping. One group included subjects with DR3 gene, and another group subjects without DR3 gene.
Results: In the subjects with DR3 gene, the frequencies of LMP2-R/H, LMP2-R/R, LMP2-H/H were 47%, 47% and 6% in the IDDM patients, 13%, 87%, 0% in the controls. Compared with the Controls, the IDDM patients had a higher frequency of LMP2-R/H (P < 0.05) and a lower frequency of LMP2-R/R (P < 0.05). In the subjects without DR3 gene, the frequencies of LMP2-R/H, LMP2-R/R, LMP2-H/H were 58%, 39%, 2.8% respectively in the IDDM patients, and 32%, 54%, 14% respectively in the controls. Compared with the controls, the IDDM patients had a higher frequency of LMP2-R/H (P < 0.05), the frequency of LMP2-R/R in the IDDM patients did not have a significant difference from that in the controls (P > 0.05).
Conclusions: There may be a significant association of LMP2-R/H and LMP2-R/R with the susceptibility to IDDM. The LMP2-R/H is a susceptible gene. The people with LMP2-R/H have a higher risk of suffering from IDDM. The LMP2-R/R is a protective gene. The people with LMP2-R/R have a decreased risk of suffering from IDDM. The effects of LMP2 on ID-DM are not affected by DR3 gene.