Familial clustering of IgA nephropathy: further evidence in an Italian population

Am J Kidney Dis. 1999 May;33(5):857-65. doi: 10.1016/s0272-6386(99)70417-8.


Several lines of evidence suggest that genetic factors have an important role in the pathogenesis of immunoglobulin A (IgA) nephropathy. We report the prevalence of familial IgA nephropathy in a referral center in northern Italy and present the data on HLA genotypes in the families identified. Twenty-six of 185 patients (14%) with IgA nephropathy investigated in Brescia, Italy, were related to at least one other patient with the disease. Restriction fragment length polymorphism (RFLP) analysis of HLA-DR beta and HLA-DQ alpha and beta genes, as well as polymerase chain reaction-based oligonucleotide typing, was performed in family members. The 26 patients with IgA nephropathy belonged to 10 families. Familial relationships between the patients varied greatly, ranging from parent-child to sib-pair to more distant familial relationships. No common nephrotoxic factor was identified in the families. The intervals separating the apparent onset of disease in relatives with IgA nephropathy varied from 8 months to 13 years. In patients with a family history of IgA nephropathy, there was an increased incidence of HLA-DRB1*08 compared with those with sporadic IgA nephropathy. The study shows that a significant number of the patients with IgA nephropathy followed up in Brescia had a family history of disease. The fact that the Italian population, an ethnic group not previously examined, also presents an increased familial susceptibility to IgA nephropathy suggests that familial predisposition is a very common finding for IgA nephropathy. Thus, clinicians should become aware that IgA nephropathy may aggregate within families in a substantial number of cases. In addition, this subgroup of patients with IgA nephropathy offers an ideal opportunity to elucidate the molecular genetics of this disease.

MeSH terms

  • Adolescent
  • Adult
  • Age of Onset
  • Aged
  • Child
  • Child, Preschool
  • Female
  • Follow-Up Studies
  • Genotype
  • Glomerulonephritis, IGA / blood
  • Glomerulonephritis, IGA / genetics*
  • Glomerulonephritis, IGA / pathology
  • Histocompatibility Testing
  • Humans
  • Italy
  • Male
  • Middle Aged
  • Pedigree