End-stage renal disease (ESRD) is a major public health problem, affecting 1 in 1,000 individuals and with an annual death rate of 20% despite dialysis treatment. IgA nephropathy (IgAN) is the most common form of glomerulonephritis, a principal cause of ESRD worldwide, affecting up to 1.3% of the population. Kidneys of patients with IgA nephropathy show deposits of IgA-containing immune complexes with proliferation of the glomerular mesangium. Typical clinical features include onset before age 40 with hematuria and proteinuria, and episodes of gross hematuria following mucosal infections are common; 30% of patients develop progressive renal failure. Although not generally considered a hereditary disease, striking ethnic variation in prevalence (Julian et al., 1985; D'Amico, 1987) and familial clustering (Scolari et al., 1999), along with subclinical renal abnormalities among relatives of cases, suggest a genetic component (Gharavi et al., 2000).
Genetic Heterogeneity of IgA Nephropathy
A locus for familial IgA nephropathy, called IGAN1, on chromosome 6q22-q23, was described by Gharavi et al. (2000). Another locus, IGAN2 (613944), was identified by Paterson et al. (2007) on chromosome 2q36. IGAN3 (616818) is caused by mutation in the SPRY2 gene (602466) on chromosome 13q31.
Polymorphisms in the ACE (106180) and AGT (106150) genes have been associated with progression to chronic renal failure in patients with IgA nephropathy. [from
OMIM]