In women with chronic kidney disease (CKD), pregnancy outcomes have improved over the last 50 years, particularly in the developed world. Maternal mortality is now extremely low, fetal survival has markedly increased (even in women with CKD stages 4-5), and it is now the exception for women with CKD to be advised against embarking on a pregnancy. However, pregnancies are rarely free from complications, and there are unanswered questions about the longer term effects on maternal and infant health. The developments have led to a more optimistic attitude to pregnancy in women with CKD not requiring renal replacement treatment. The remaining problems are described in this World Kidney Forum.

Baines RJ, Chana RS, Hall M, Febbraio M, Kennedy D, Brunskill NJ. CD36 mediates proximal tubular binding and uptake of albumin and is upregulated in proteinuric nephropathies. Am J Physiol

Since the emergency of novel coronavirus COVID-19 (SARS-CoV-2) in December 2019, infections have spread rapidly across the world. The reported incidence of acute kidney injury (AKI) in the context of COVID-19 is variable, and its mechanism is not well understood. Data are emerging about possible mechanisms of AKI including virus-induced cytopathic effect and cytokine storm-induced injury. To date, there have been few reports of kidney biopsy findings in the context of AKI in COVID-19 infection. This article describes 2 cases of collapsing glomerulopathy, 1 in a native kidney and, for the first time, 1 in a kidney transplant. Both individuals were black, and both presented without significant respiratory compromise. Indeed, the 2 patients we describe remained systemically well for the majority of their inpatient stay, which would support the hypothesis that for these patients, AKI was caused by a cytopathic viral effect, rather than that of a cytokine storm or acute tubular necrosis caused by prolonged hypovolaemia or the effect of medication known to exacerbate AKI. Here, we report 2 cases of AKI with collapsing glomerulopathy in COVID-19, one of which is in a kidney transplant recipient, not previously described elsewhere.

BackgroundPrimary membranoproliferative GN, including complement 3 (C3) glomerulopathy, is a rare, untreatable kidney disease characterized by glomerular complement deposition. Complement gene mutations can cause familial C3 glomerulopathy, and studies have reported rare variants in complement genes in nonfamilial primary membranoproliferative GN.MethodsWe analyzed whole-genome sequence data from 165 primary membranoproliferative GN cases and 10,250 individuals without the condition (controls) as part of the National Institutes of Health Research BioResource–Rare Diseases Study. We examined copy number, rare, and common variants.ResultsOur analysis included 146 primary membranoproliferative GN cases and 6442 controls who were unrelated and of European ancestry. We observed no significant enrichment of rare variants in candidate genes (genes encoding components of the complement alternative pathway and other genes associated with the related disease atypical hemolytic uremic syndrome; 6.8% in cases versus 5.9% in controls) or exome-wide. However, a significant common variant locus was identified at 6p21.32 (rs35406322) (P=3.29×10−8; odds ratio [OR], 1.93; 95% confidence interval [95% CI], 1.53 to 2.44), overlapping the HLA locus. Imputation of HLA types mapped this signal to a haplotype incorporating DQA1*05:01, DQB1*02:01, and DRB1*03:01 (P=1.21×10−8; OR, 2.19; 95% CI, 1.66 to 2.89). This finding was replicated by analysis of HLA serotypes in 338 individuals with membranoproliferative GN and 15,614 individuals with nonimmune renal failure.ConclusionsWe found that HLA type, but not rare complement gene variation, is associated with primary membranoproliferative GN. These findings challenge the paradigm of complement gene mutations typically causing primary membranoproliferative GN and implicate an underlying autoimmune mechanism in most cases.