OBJECTIVE

To investigate the association of the polymorphism of NPHS1, coding gene of nephrin, with the degree of proteinuria, renal function, and prognosis of IgA nephropathy (IgAN) in patients in north China.

METHODS

Peripheral blood samples were collected from 532 patients with IgAN confirmed by biopsy, 285 males and 230 females, aged (31+/-11). Genomic DNA was isolated from the peripheral blood leucocytes. Polymorphism of the exon G349A of NPHS1 was detected by polymerase chain reaction combined with restriction fragment length polymorphism (PCR-RFLP). 138 patients were followed up for 4-99 months. The correlation between the NPHS1 polymorphism and renal function at the time of renal biopsy, and that between NPHS1 polymorphism and the prognosis were analyzed.

RESULTS

The frequency of the genotype with the allele G (AG/GG) in the patients with the estimated glomerular filtration rate (eGFR)<60 mlxmin(-1)x(1.73 m2)(-1) was significantly higher than that of the patients with the eGFR>60 ml.min(-1)x(1.73 m2)(-1) (P=0.008). Even after adjusting for the effects of proteinuria, hypertension, and age, AG/GG genotype was an independent risk factor of the exacerbation of renal damage at the time of diagnosis (P=0.011), and GG genotype was an independent risk factor of the prognosis (P<0.001).

CONCLUSIONS

G allele and AG/GG genotype are associated with the severity of renal function at the time of diagnosis the GG genotype is associated with the prognosis of IgAN patients.