Outcomes in biopsy-proven lupus nephritis: evaluation of 190 white patients from a single center.

We describe the natural history of lupus nephritis (LN) in a historical cohort of 190 white patients with the diagnosis of biopsy-proven LN followed in a single reference center.We evaluated 670 patients with systemic lupus erythematosus (SLE) consecutively followed in our department from 1970 until 2006. All patients fulfilled the 1997 revised criteria for the classification of SLE. White patients (Spanish-born) with biopsy-proven LN were selected as the study population.The cohort included 190 patients (170 female patients and 20 male) with a mean age at LN diagnosis of 31 years. Renal biopsy revealed type I LN in 8 (4%) patients, type II in 33 (17%), type III in 46 (24%), type IV in 72 (38%), type V in 28 (15%), and type VI in 3 (2%) patients. Induction remission was achieved in 85% of patients with types I and II, 78% with type III, 70% with type IV, and 32% of patients with type V. After a mean follow-up of 2391 patient-years, 62 (33%) patients developed chronic renal failure and 18 (9%) evolved to end-stage renal disease. Adjusted multivariate Cox regression analysis identified male sex (hazard ratio [HR], 4.33) and elevated creatinine at LN diagnosis (HR, 5.18) as independent variables for renal failure. Survival was 92% at 10 years of follow-up, 80% after 20 years, and 72% after 30 years.Our results suggest that biopsy-proven LN in white patients has an excellent prognosis. Ethnicity should be considered a key factor when evaluating the prognosis and therapeutic response to different agents in patients with LN.

Autosomal recessive Alport's syndrome and benign familial hematuria are collagen type IV diseases.

BACKGROUND: Alport's syndrome (AS) is a genetically heterogeneous renal hereditary disease. Mutations in collagen type IV genes have been described to be responsible for X-linked (COL4A5), autosomal recessive, and autosomal dominant AS (COL4A3/COL4A4). Moreover, at least 40% of benign familial hematuria (BFH) cases cosegregate with the COL4A3/COL4A4 loci, following a dominant pattern of inheritance. Therefore, it has been suggested that BFH may represent the carrier state for autosomal recessive AS. METHODS: We report a mutational study of the COL4A3 and COL4A4 genes in 14 AS and 2 BFH families. When possible, linkage analysis has been performed to confirm the pattern of inheritance. One affected proband from each family underwent mutation screening by single-strand conformation polymorphism/heteroduplex analysis. RESULTS: We identified 13 mutations within the COL4A3 gene and 2 mutations within the COL4A4 gene, 9 of which are first reported here. We also detected 14 polymorphisms within the COL4A3 gene and 15 polymorphisms within the COL4A4 gene, 7 of them not previously described. In 2 of our AS families, we found mutations previously reported for BFH, and we characterized a novel mutation shared by an AS and a BFH family. CONCLUSION: Collagen type IV nephropathy is an entity in itself, and phenotypic manifestations of COL4A3/COL4A4 mutations may range from monosymptomatic hematuria (BFH) to severe renal failure (AS), depending on the gene dosage. In 3 of our families, we genetically confirmed that BFH represents the carrier state for autosomal recessive AS.

Mutations in theCOL4A4 and COL4A3 genes cause familial benign hematuria.

Familial benign hematuria (FBH) is a common autosomal dominant disorder characterized by the presence of persistent or recurrent hematuria. The clinical and pathologic features of this syndrome resemble those of early Alport syndrome (AS), and for this reason a common molecular defect has been proposed. The COL4A3/4 genes seem to be involved in both autosomal AS and FBH. This study involves a linkage analysis for the COL4A3/4 loci and a search for mutations within these genes in 11 biopsy-proven FBH families. Haplotype analysis showed that linkage to the COL4A3/4 locus could not be excluded in eight of nine families. One family was not linked to this locus; however, it included three affected women who could be X-linked AS carriers. Two families were too small to perform linkage analysis. COL4A3 and COL4A4 mutation screening disclosed six new pathogenic mutations, two in the COL4A3 gene (G985V and G1015E) and four in the COL4A4 gene (3222insA, IVS23-1G>C, 31del11, and G960R). It is the first time that mutations within the COL4A3 gene are described in families with FBH. This study clearly demonstrates the main role of the COL4A4 and COL4A3 genes in the pathogenesis of FBH.