The molecular basis of interindividual clinical variability upon infection with Staphylococcus aureus is unclear. We describe patients with haploinsufficiency for the linear deubiquitinase OTULIN, encoded by a gene on chromosome 5p. Patients suffer from episodes of life-threatening necrosis, typically triggered by S. aureus infection. The disorder is phenocopied in patients with the 5p− (Cri-du-Chat) chromosomal deletion syndrome. OTULIN haploinsufficiency causes an accumulation of linear ubiquitin in dermal fibroblasts, but tumor necrosis factor receptor–mediated nuclear factor κB signaling remains intact. Blood leukocyte subsets are unaffected. The OTULIN-dependent accumulation of caveolin-1 in dermal fibroblasts, but not leukocytes, facilitates the cytotoxic damage inflicted by the staphylococcal virulence factor α-toxin. Naturally elicited antibodies against α-toxin contribute to incomplete clinical penetrance. Human OTULIN haploinsufficiency underlies life-threatening staphylococcal disease by disrupting cell-intrinsic immunity to α-toxin in nonleukocytic cells.

Glomerular nephropathy resulting from the genetic defects in COL4A3/4/5 genes including the classical Alport syndrome is the second most common hereditary kidney disease characterized by persistent haematuria progressing to the need for kidney replacement therapy, frequently associated with sensorineural deafness, and occasionally with ocular anomalies. Diagnosis and management of COL4A3/4/5 glomerulopathy is a great challenge due to its phenotypic heterogeneity, multiple modes of inheritance, variable expressivity, and disease penetrance of individual variants as well as imperfect prognostic and progression factors and scarce and limited clinical trials, especially in children. As a joint initiative of the European Rare Kidney disease reference Network (ERKNet), European Renal Association (ERA Genes&Kidney), and European Society for Paediatric Nephrology (ESPN) Inherited renal disorders working group, a team of experts including adult and paediatric nephrologists, kidney geneticists, audiologists, ophthalmologists, and a kidney pathologist were selected to perform a systematic literature review on 21 clinically relevant PICO (Patient or Population covered, Intervention, Comparator, Outcome) questions. The experts formulated recommendations and formally graded them at a consensus meeting with input from patient representatives and a voting panel of nephrologists representing all regions of the world. Genetic diagnostics comprising joint analysis of COL4A3/4/5 genes is already the key diagnostic test during the initial evaluation of an individual presenting with persistent haematuria, proteinuria, kidney failure of unknown origin, focal segmental sclerosis of unknown origin, and possibly cystic kidney disease. Early renin-angiotensin system blockade is the standard of care therapy; sodium-glucose cotransporter-2 inhibitors may be added in adults with proteinuria and chronic kidney disease. Relatives with heterozygous COL4A3/4/5 variants should only be considered as the last possible resource for living kidney donation. This guideline provides guidance for the diagnosis and management of individuals with pathogenic variants in COL4A3/4/5 genes.

Distal renal tubular acidosis (dRTA) is characterized by an impaired ability of the distal tubule to excrete acid, leading to metabolic acidosis. Associated complications include bone disease, growth failure, urolithiasis and hypokalaemia. Due to its rarity, there is limited evidence to guide diagnosis and management; however, available data strongly suggest that metabolic control of the acidosis by alkali supplementation can halt or revert almost all complications. Despite this, cohort studies show that adequate metabolic control is present in only about half of patients, highlighting problems with treatment provision or adherence. With these clinical practice points the authors, part of the working groups tubulopathies in the European Rare Kidney Disease Reference network and inherited kidney diseases of the European Society for Paediatric Nephrology, aim to provide guidance for the management of patients with dRTA to facilitate adequate treatment and establish an initial best practice standard against which treatment of patients can be audited.