A hybrid CFHR3-1 gene causes familial C3 glomerulopathy.

Controlled activation of the complement system, a key component of innate immunity, enables destruction of pathogens with minimal damage to host tissue. Complement factor H (CFH), which inhibits complement activation, and five CFH-related proteins (CFHR1-5) compose a family of structurally related molecules. Combined deletion of CFHR3 and CFHR1 is common and confers a protective effect in IgA nephropathy. Here, we report an autosomal dominant complement-mediated GN associated with abnormal increases in copy number across the CFHR3 and CFHR1 loci. In addition to normal copies of these genes, affected individuals carry a unique hybrid CFHR3-1 gene. In addition to identifying an association between these genetic observations and complement-mediated kidney disease, these results provide insight into the protective role of the combined deletion of CFHR3 and CFHR1 in IgA nephropathy.

Pyroglutamic acidosis in association with therapeutic paracetamol use.

Long-term use of paracetamol (at therapeutic doses) can cause the accumulation of endogenous organic pyroglutamate, resulting in metabolic acidosis with an elevated anion gap. This occurs in the presence of malnutrition, infection, antibiotic use, renal failure and pregnancy. Given the prevalence of these risk factors, this condition is thought to be relatively common in a hospitalised population but is probably significantly underdiagnosed. Prompt recognition is essential because the condition is entirely reversible if the causative agents are withdrawn.Here we describe five cases of pyroglutamic acidosis that we have encountered in a tertiary referral hospital. Together they illustrate the common clinical risk factors and the excellent prognosis, once a diagnosis is made. We describe how a rudimentary acid-base analysis (calculation of the anion gap) usually leads to the diagnosis but how a more nuanced approach may be required in the presence of mixed acid-base disorders.

Renal artery stenosis is not associated with the development of acute renal failure following coronary artery bypass grafting.

BACKGROUND: Acute renal failure (ARF) is a frequent complication of coronary artery bypass grafting (CABG) surgery and is strongly associated with perioperative morbidity and mortality. We hypothesized that renal artery stenosis (RAS), causing occult renal ischemia, may be an important factor contributing to development of ARF after CABG surgery. METHODS: Preoperative and intraoperative data on 798 consecutive adult patients undergoing CABG surgery with cardiopulmonary bypass from February 1, 1995 to February 1, 1997 (who had also undergone an abdominal aortogram for the evaluation of RAS) were recorded and entered into a computerized database. The development of ARF was defined as a rise in serum creatinine of 1 mg/dL (88.4 micromol/L) above baseline postoperatively. The association between the presence of renal artery stenosis together with preoperative and intraoperative variables and the development of ARF was assessed by multivariate logistic regression. RESULTS: A total of 798 patients underwent isolated coronary bypass grafting, of which 18.7% demonstrated 50% or more RAS. ARF developed in 82 patients (10.2%), of which three (0.3%) required dialysis support. The mortality for patients who developed ARF was 14% (OR 15, P=0.0001) compared to 0.2% among those who did not develop ARF. The presence of renal artery stenosis of any severity ranging from unilateral 50% RAS to bilateral 95% RAS was not associated with the subsequent development of ARF. CONCLUSIONS: The development of ARF following CABG surgery is associated with high mortality. The presence of RAS does not appear to increase the risk for developing ARF.

Linkage of a gene causing familial membranoproliferative glomerulonephritis type III to chromosome 1.

Membranoproliferative glomerulonephritis (MPGN) type III is a chronic progressive renal disease of unknown cause. The diagnosis is based on renal pathologic features (specifically immunofluorescence staining patterns and ultrastructural appearance). Mesangial cell proliferation and subendothelial and subepithelial deposits characterize the renal disease. Although the actual prevalence of this disease is not known, the disease is rare and usually sporadic. The clinical features of MPGN include the nephrotic syndrome and hematuria, with renal dysfunction occurring in approximately 50% of patients. Progression to end-stage renal disease is variable, and some patients exhibit stabilization or even improvement. Here is presented an Irish family in which there are eight affected members in four generations, suggesting autosomal dominant inheritance. This is the only reported family with an inherited form of MPGN type III. To evaluate the disease in this family, a genome-wide scan was performed with a panel of 402 polymorphic microsatellite markers, defining a grid with an average resolution of 10 cM (centimorgans). Significant evidence for linkage was observed on chromosome 1q31-32, with a maximal logarithm of the odds score of 3.86 at theta = 0.00 for microsatellite marker GATA135F02. Recombination events among affected individuals, as detected by haplotype analysis, established a 22-cM minimal candidate region flanked by markers D1S3470 and GATA124F08. The data provide evidence for a gene for familial MPGN on chromosome 1q.