Do the mutations of C1GALT1C1 gene play important roles in the genetic susceptibility to Chinese IgA nephropathy?

Background: The deficiency of beta1,3 galactose in hinge region of IgA1 molecule played a pivotal role in pathogenesis of IgA nephropathy (IgAN). Cosmc, encoded by C1GALT1C1 gene, was indispensable to beta1,3 galactosylation of IgA1. We designed a serial study to investigate the relationship between the mutations of C1GALT1C1 gene and the genetic susceptibility to IgAN.

Methods: Nine hundred and thirty-eight subjects, including 661 patients with IgAN and 277 healthy controls were enrolled in the study. Firstly, single nucleotide polymorphisms (SNPs) in the promoter region of C1GALT1C1 gene were screened. Then the c.-347-190G>A was analyzed by PCR-restriction fragment length polymorphism (PCR-RFLP) for further case-control association analysis. Secondly the somatic mutations of DNAs from peripheral blood B lymphocytes were detected in 15 patients and 7 normal controls.

Results: No significant association was observed between the different alleles or genotypes of c.-347-190G>A and IgAN. The patients with different genotypes of C1GALT1C1 gene did not significantly associate with clinical manifestations, including hematuria, proteinuria, and serum creatinine of patients with IgAN. There was no somatic mutation detected in total 202 clones of 22 individuals.

Conclusion: The c.-347-190G>A polymorphism and the somatic mutation of encoding region of C1GALT1C1 gene were not significantly related to the genetic susceptibility to IgAN in Northern Chinese population.