BACKGROUND: The course of glomerulonephritis varies even within the same histological entity, which suggest that genetic factors determine the progression of inflammatory renal diseases. We studied a potential relationship between the C242T gene polymorphism of p22(phox), a subunit of the NAD(P)H oxidase, and frequency as well as progression of immunoglobulin A (IgA) nephropathy. Patients with lupus nephritis were also investigated. The distribution of the C242T gene variation of p22(phox) has not been previously studied in patients with renal disease. METHODS: Patients with IgA nephropathy were from a homogenous ethnic group of patients living in Northern Germany (n=127). Patients with active lupus nephritis WHO classes III/IV (n=46) were also studied. All diagnoses were confirmed by renal biopsy. Healthy blood donors (n=151) exhibited a genotype distribution similar to previously reported values for Caucasians (CC, 41.2%; CT, 45%; TT, 13.8%). However, C242T genotype distribution was not significantly different (chi(2) test) in patients with IgA nephropathy (CC, 44.9%; CT, 48%; TT, 7.1%) or in active lupus nephritis (CC, 54.3%; CT, 34.7%; TT, 11%). Grouping of IgA nephropathy patients as those with mild renal impairment at the time of biopsy (serum creatinine 1.3 mg/dl) also failed to show a relationship with p22(phox) polymorphism. Log-rank analysis for up to 15 years in selected cases of IgA nephropathy did not show a significant difference in renal survival rate among the three genotypes. CONCLUSIONS: It appears that the C242T polymorphism is not associated with IgA nephropathy or active lupus nephritis and may not affect the progressive deterioration of renal function in patients with IgA nephropathy. However, whether the C242T polymorphism plays a role in other renal diseases remains to be studied.
