腎臓学と治療学ジャーナル

IgA Nephropathy: Actually an Inherited Disease?

Abstract

Dimitrios Kirmizis *

IgA Nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. Over the last years strong evidence suggest the existence of genetic factors in the development and/or progression of IgAN. IgAN does not exhibit classic single-gene Mendelian but rather a complex genetic inheritance pattern. Until now, two basic approaches have been used in genetic studies of IgAN: Genome-Wide linkage Analysis Studies (GWAS) and candidate-gene association studies. Many candidates have been proposed, but most were studied in the context of IgAN progression rather than causality. In addition, in part due to our lack of knowledge about disease pathogenesis, most candidates were predicated on sparse a priori evidence for involvement in IgAN. Overall, candidate-gene studies for IgAN have been largely unrevealing. The advantage of GWAS, on the other hand, is that they do not require a priori assumptions about disease pathogenesis. To date six GWAS of familial IgAN have identified several loci located on chromosomes 2, 4, 6, 7, 12 and 17. The functional mapping of genes involved in the disease is anticipated to proceed further from the identification of susceptibility loci identified by linkage analysis to the isolation of candidate genes within gene diseasesusceptibility loci. In conclusion, inheritance of IgAN follows a complex genetic pattern, most probably autosomal dominant inheritance with incomplete penetrance. It seems that several genetic loci contribute significantly to the disease susceptibility that underlies the primary immunologic defects observed in IgAN.