title: Familial clustering of IgA nephropathy: further evidence in an Italian population.
abstract: 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.
authors.affiliation: Division of Nephrology, Spedali Civili, Brescia, Italy. fscolar@tin.it
authors.forename: F
authors.initials: F
authors.lastname: Scolari
authors.forename: A
authors.initials: A
authors.lastname: Amoroso
authors.forename: S
authors.initials: S
authors.lastname: Savoldi
authors.forename: G
authors.initials: G
authors.lastname: Mazzola
authors.forename: E
authors.initials: E
authors.lastname: Prati
authors.forename: B
authors.initials: B
authors.lastname: Valzorio
authors.forename: B F
authors.initials: BF
authors.lastname: Viola
authors.forename: B
authors.initials: B
authors.lastname: Nicola
authors.forename: E
authors.initials: E
authors.lastname: Movilli
authors.forename: M
authors.initials: M
authors.lastname: Sandrini
authors.forename: M
authors.initials: M
authors.lastname: Campanini
authors.forename: R
authors.initials: R
authors.lastname: Maiorca
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D005922:Glomerulonephritis, IGA / Q000097:blood / Q000235:genetics* / Q000473:pathology; D006650:Histocompatibility Testing; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D010375:Pedigree