OBJECTIVETo explore the characteristics in CFHR1 concentration and the frequency of CFHR1 gene polymorphisms of patients with type 2 diabetes mellitus (T2DM) based on the high level of complement factor H (CFH) expression among such patients and the similarity between CFHR1 and CFH in terms of sequence and functions.

METHODSFifty T2DM patients and 30 healthy controls were selected. The plasma samples were separated by pI with OFFGEL electrophoresis following solution digestion. Further separation and identification were carried out on a Nano HPLC-Chip-MS/MS system. Differentially expressed proteins were identified by comparison. Enzyme-linked immunosorbent assay (ELISA) was used to validate the result. Genomic DNA of the two groups was extracted. Polymerase chain reaction and sequencing were used to determine the single nucleotide polymorphisms in the 6 exons of the CFHR1 gene.

RESULTSThe CFHR1 level in plasma of T2DM patients were significantly higher than that of the healthy controls (P=2.78× 10). A significant difference in allelic frequencies of rs12406079 of the fifth exon of the CFHR1 gene was found between the two groups (χ=5.692, P=0.017).

CONCLUSIONThe concentration of CFHR1 and frequencies of CFHR1 gene polymorphisms among patients with T2DM differ significantly from healthy subjects. Polymorphisms of the CFHR1 gene are associated with T2DM.