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Key Points: • Lademirsen, an anti–microRNA-21 therapy, was generally well-tolerated in adults with Alport syndrome at risk of rapid disease progression. • There were no significant differences between lademirsen-treated and placebo-treated participants in eGFR at any timepoint. • The proportions of participants with prespecified reductions in eGFR at weeks 24 and 48 were not significantly different for lademirsen versus placebo. Background: Preclinical models of disease have suggested that targeting microRNA-21 (miRNA-21) may slow the decline in kidney function in individuals with Alport syndrome (AS). The objective of this study was to investigate the effects of the anti–miRNA-21 oligonucleotide, lademirsen, on rate of eGFR decline in adults with AS at risk of rapid disease progression. Methods: This study was a phase 2 trial of lademirsen, with a randomized, double-blind, placebo-controlled period followed by an open-label period. Adults with AS, eGFR >35 to <90 ml/min per 1.73 m2, and evidence of rapidly progressive kidney dysfunction were randomized 2:1 to lademirsen 110 mg subcutaneously once weekly or placebo for 48 weeks. After a planned interim analysis (after 24 of 43 randomized participants completed the week 48 study visit or discontinued before week 48), the trial was terminated for futility. Results: Forty-three adults with AS (26 men, 17 women) participated (mean age 34 years), and 28 (lademirsen: n=19; placebo: n=9) completed 48 weeks of double-blind treatment. All participants in both groups developed treatment-emergent adverse events, mainly respiratory tract infections, headache, dizziness, metabolic/electrolyte disturbances, and anemia. Treatment was discontinued in three lademirsen-treated participants in the double-blind period and one participant in the open-label period, owing to treatment-emergent adverse events. The least squares mean eGFR slope (95% confidence interval) over 48 weeks in the lademirsen and placebo groups was −5 (−8.7 to −1.1

Numerous genes for monogenic kidney diseases with classical patterns of inheritance, as well as genes for complex kidney diseases that manifest in combination with environmental factors, have been discovered. Genetic findings are increasingly used to inform clinical management of nephropathies, and have led to improved diagnostics, disease surveillance, choice of therapy, and family counseling. All of these steps rely on accurate interpretation of genetic data, which can be outpaced by current rates of data collection. In March of 2021, Kidney Diseases: Improving Global Outcomes (KDIGO) held a Controversies Conference on "Genetics in Chronic Kidney Disease (CKD)" to review the current state of understanding of monogenic and complex (polygenic) kidney diseases, processes for applying genetic findings in clinical medicine, and use of genomics for defining and stratifying CKD. Given the important contribution of genetic variants to CKD, practitioners with CKD patients are advised to "think genetic," which specifically involves obtaining a family history, collecting detailed information on age of CKD onset, performing clinical examination for extrarenal symptoms, and considering genetic testing. To improve the use of genetics in nephrology, meeting participants advised developing an advanced training or subspecialty track for nephrologists, crafting guidelines for testing and treatment, and educating patients, students, and practitioners. Key areas of future research, including clinical interpretation of genome variation, electronic phenotyping, global representation, kidney-specific molecular data, polygenic scores, translational epidemiology, and open data resources, were also identified.

Diseases of the glomerular basement membrane (GBM), such as Goodpasture's disease (GP) and Alport syndrome (AS), are a major cause of chronic kidney failure and an unmet medical need. Collagen IValpha345 is an important architectural element of the GBM that was discovered in previous research on GP and AS. How this collagen enables GBM to function as a permselective filter and how structural defects cause renal failure remain an enigma. We found a distinctive genetic variant of collagen IValpha345 in both a familial GP case and four AS kindreds that provided insights into these mechanisms. The variant is an 8-residue appendage at the C-terminus of the alpha3 subunit of the alpha345 hexamer. A knock-in mouse harboring the variant displayed GBM abnormalities and proteinuria. This pathology phenocopied AS, which pinpointed the alpha345 hexamer as a focal point in GBM function and dysfunction. Crystallography and assembly studies revealed underlying hexamer mechanisms, as described in Boudko et al. and Pedchenko et al. Bioactive sites on the hexamer surface were identified where pathogenic pathways of GP and AS converge and, potentially, that of diabetic nephropathy (DN). We conclude that the hexamer functions include signaling and organizing macromolecular complexes, which enable GBM assembly and function. Therapeutic modulation or replacement of alpha345 hexamer could therefore be a potential treatment for GBM diseases, and this knock-in mouse model is suitable for developing gene therapies.Copyright © 2021 THE AUTHORS. Published by Elsevier Inc on behalf of American Society for Biochemistry and Molecular Biology. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Diseases of the glomerular basement membrane (GBM), such as Goodpasture's disease (GP) and Alport syndrome (AS), are a major cause of chronic kidney failure and an unmet medical need. Collagen IValpha345 is an important architectural element of the GBM that was discovered in previous research on GP and AS. How this collagen enables GBM to function as a permselective filter and how structural defects cause renal failure remain an enigma. We found a distinctive genetic variant of collagen IValpha345 in both a familial GP case and four AS kindreds that provided insights into these mechanisms. The variant is an 8-residue appendage at the C-terminus of the alpha3 subunit of the alpha345 hexamer. A knock-in mouse harboring the variant displayed GBM abnormalities and proteinuria. This pathology phenocopied AS, which pinpointed the alpha345 hexamer as a focal point in GBM function and dysfunction. Crystallography and assembly studies revealed underlying hexamer mechanisms, as described in Companion Papers II and III. Bioactive sites on the hexamer surface were identified where pathogenic pathways of GP and AS converge, and, potentially, that of diabetic nephropathy (DN). We conclude that the hexamer functions include signaling and organizing macromolecular complexes, which enable GBM assembly and function. Therapeutic modulation or replacement of alpha345 hexamer could therefore be a potential treatment for GBM diseases, and this knock-in mouse model is suitable for developing gene therapies.Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.