Mutations in KEOPS-Complex Genes Cause Nephrotic Syndrome with Primary Microcephaly

Galloway-Mowat syndrome (GAMOS) is an autosomal-recessive disease characterized by the combination of early-onset nephrotic syndrome (SRNS) and microcephaly with brain anomalies. Here we identified recessive mutations in OSGEP, TP53RK, TPRKB, and LAGE3, genes encoding the four subunits of the KEOPS complex, in 37 individuals from 32 families with GAMOS. CRISPR-Cas9 knockout in zebrafish and mice recapitulated the human phenotype of primary microcephaly and resulted in early lethality. Knockdown of OSGEP, TP53RK, or TPRKB inhibited cell proliferation, which human mutations did not rescue. Furthermore, knockdown of these genes impaired protein translation, caused endoplasmic reticulum stress, activated DNA-damage-response signaling, and ultimately induced apoptosis. Knockdown of OSGEP or TP53RK induced defects in the actin cytoskeleton and decreased the migration rate of human podocytes, an established intermediate phenotype of SRNS. We thus identified four new monogenic causes of GAMOS, describe a link between KEOPS function and human disease, and delineate potential pathogenic mechanisms

Diagnosis and Risk Factors of Acute Kidney Injury in Very Low Birth Weight Infants

Acute kidney injury (AKI) is common in critically ill premature infants. There is a lack of consensus on the diagnostic definition of AKI in very low birth weight (VLBW) infants. The primary aim of this study was to determine the incidence and risk factors for AKI in VLBW infants using the AKI network (AKIN) and pRIFLE (pediatric Risk, Injury, Failure, Loss, End-Stage) criteria and to evaluate whether Clinical Risk Index for Babies (CRIB II) score is a predictor of AKI. The secondary objective was to determine the extent of agreement between the AKIN and pRIFLE criteria in the diagnosis of AKI in VLBW infants. Methods: This was a retrospective chart review of 115 VLBW (< 1500 g) infants born in an academic center with a Level 3B neonatal intensive care unit. Multiple congenital anomalies, transfer to other centers, or death within the first 2 weeks were the exclusion criteria. Relevant data were collected and analyzed in the first 2 weeks postnatally. Results: AKI incidence, according to AKIN and pRIFLE criteria, was 20.1% and 22.6%, respectively. As per the interrater reliability analysis, there was a fair agreement between the two criteria (kappa = 0.217). AKI was nonoliguric. The length of stay was significantly longer in the AKI group. Prenatal nonsteroidal anti-inflammatory drug exposure, lower gestational age, lower birth weight, respiratory distress syndrome, mechanical ventilation, patent ductus arteriosus, hypotension, late onset sepsis, and higher CRIB II scores were significantly associated with AKI. Our regression analysis found CRIB II scores to be an independent risk factor for AKI (odds ratio = 1.621; 95% confidence interval, 1.230–2.167; p = 0.001). Conclusion: The determination of AKI using the pRIFLE and AKIN criteria yielded different results. pRIFLE appears to be more sensitive in VLBW infants. A high CRIB II score was recorded for AKI. Future studies are necessary to develop a uniform definition and identify the risk factors to improve the outcomes in this population

Gene panel sequencing identifies a likely monogenic cause in 7% of 235 Pakistani families with nephrolithiasis

Nephrolithiasis (NL) affects 1 in 11 individuals worldwide and causes significant patient morbidity. We previously demonstrated a genetic cause of NL can be identified in 11-29% of pre-dominantly American and European stone formers. Pakistan, which resides within the Afro-Asian stone belt, has a high prevalence of nephrolithiasis (12%) as well as high rate of consanguinity (> 50%). We recruited 235 Pakistani subjects hospitalized for nephrolithiasis from five tertiary hospitals in the Punjab province of Pakistan. Subjects were surveyed for age of onset, NL recurrence, and family history. We conducted high-throughput exon sequencing of 30 NL disease genes and variant analysis to identify monogenic causative mutations in each subject. We detected likely causative mutations in 4 of 30 disease genes, yielding a likely molecular diagnosis in 7% (17 of 235) of NL families. Only 1 of 17 causative mutations was identified in an autosomal recessive disease gene. 10 of the 12 detected mutations were novel mutations (83%). SLC34A1 was most frequently mutated (12 of 17 solved families). We observed a higher frequency of causative mutations in subjects with a positive NL family history (13/109, 12%) versus those with a negative family history (4/120, 3%). Five missense SLC34A1 variants identified through genetic analysis demonstrated defective phosphate transport. We examined the monogenic causes of NL in a novel geographic cohort and most frequently identified dominant mutations in the sodium-phosphate transporter SLC34A1 with functional validation

Genetic variants in the LAMA5 gene in pediatric nephrotic syndrome.

Nephrotic syndrome (NS), a chronic kidney disease, is characterized by significant loss of protein in the urine causing hypoalbuminemia and edema. In general, ∼15% of childhood-onset cases do not respond to steroid therapy and are classified as steroid-resistant NS (SRNS). In ∼30% of cases with SRNS, a causative mutation can be detected in one of 44 monogenic SRNS genes. The gene LAMA5 encodes laminin-α5, an essential component of the glomerular basement membrane. Mice with a hypomorphic mutation in the orthologous gene Lama5 develop proteinuria and hematuria

Acute kidney injury requiring kidney replacement therapy in childhood lupus nephritis: a cohort study of the Pediatric Nephrology Research Consortium and Childhood Arthritis and Rheumatology Research Alliance

Acute kidney injury (AKI) is common in lupus nephritis (LN) and a risk factor for development of chronic kidney disease. In adults with LN, AKI severity correlates with the incidence of kidney failure and patient survival. Data on AKI outcomes in children with LN, particularly those requiring kidney replacement therapy (KRT), are limited. A multicenter, retrospective cohort study was performed in children diagnosed between 2010 and 2019 with LN and AKI stage 3 treated with dialysis (AKI stage 3D). Descriptive statistics were used to characterize demographics, clinical data, and kidney biopsy findings; treatment data for LN were not included. Logistic regression was used to examine the association of these variables with kidney failure. Fifty-nine patients (mean age 14.3 years, 84.7% female) were identified. The most common KRT indications were fluid overload (86.4%) and elevated blood urea nitrogen/creatinine (74.6%). Mean follow-up duration was 3.9 ± 2.9 years. AKI recovery without progression to kidney failure occurred in 37.3% of patients. AKI recovery with later progression to kidney failure occurred in 25.4% of patients, and there was no kidney recovery from AKI in 35.6% of patients. Older age, severe (> 50%) tubular atrophy and interstitial fibrosis, and National Institutes of Health (NIH) chronicity index score > 4 on kidney biopsy were associated with kidney failure. Children with LN and AKI stage 3D have a high long-term risk of kidney failure. Severe tubular atrophy and interstitial fibrosis at the time of AKI, but not AKI duration, are predictive of kidney disease progression. A higher resolution version of the Graphical abstract is available as Supplementary information

GAPVD1 and ANKFY1 Mutations Implicate RAB5 Regulation iotic Syndrome.n Nephr

BACKGROUND: Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of CKD. The discovery of monogenic causes of SRNS has revealed specific pathogenetic pathways, but these monogenic causes do not explain all cases of SRNS. METHODS: To identify novel monogenic causes of SRNS, we screened 665 patients by whole-exome sequencing. We then evaluated the RESULTS: We identified conserved, homozygous missense mutations of CONCLUSIONS: Mutations i

Genetic variants in the LAMA5 gene in pediatric nephrotic syndrome

Background Nephrotic syndrome (NS), a chronic kidney disease, is characterized by significant loss of protein in the urine causing hypoalbuminemia and edema. In general, approximate to 15\% of childhood-onset cases do not respond to steroid therapy and are classified as steroid-resistant NS (SRNS). In approximate to 30\% of cases with SRNS, a causative mutation can be detected in one of 44 monogenic SRNS genes. The gene LAMA5 encodes laminin-5, an essential component of the glomerular basement membrane. Mice with a hypomorphic mutation in the orthologous gene Lama5 develop proteinuria and hematuria. Methods To identify additional monogenic causes of NS, we performed whole exome sequencing in 300 families with pediatric NS. In consanguineous families we applied homozygosity mapping to identify genomic candidate loci for the underlying recessive mutation. Results In three families, in whom mutations in known NS genes were excluded, but in whom a recessive, monogenic cause of NS was strongly suspected based on pedigree information, we identified homozygous variants of unknown significance (VUS) in the gene LAMA5. While all affected individuals had nonsyndromic NS with an early onset of disease, their clinical outcome and response to immunosuppressive therapy differed notably. Conclusion We here identify recessive VUS in the gene LAMA5 in patients with partially treatment-responsive NS. More data will be needed to determine the impact of these VUS in disease management. However, familial occurrence of disease, data from genetic mapping and a mouse model that recapitulates the NS phenotypes suggest that these genetic variants may be inherited factors that contribute to the development of NS in pediatric patients

Advillin acts upstream of phospholipase C is an element of 1 in steroid-resistant nephrotic syndrome

WOS: 000417141100007PubMed ID: 29058690Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of chronic kidney disease. Here, we identified recessive mutations in the gene encoding the actin-binding protein advillin (AVIL) in 3 unrelated families with SRNS. While all AVIL mutations resulted in a marked loss of its actin-bundling ability, truncation of AVIL also disrupted colocalization with F-actin, thereby leading to impaired actin binding and severing. Additionally, AVIL colocalized and interacted with the phospholipase enzyme PLCE1 and with the ARP2/3 actin-modulating complex. Knockdown of AVIL in human podocytes reduced actin stress fibers at the cell periphery, prevented recruitment of PLCE1 to the ARP3-rich lamellipodia, blocked EGF-induced generation of diacylglycerol (DAG) by PLCE1, and attenuated the podocyte migration rate (PMR). These effects were reversed by overexpression of WT AVIL but not by overexpression of any of the 3 patient-derived AVIL mutants. The PMR was increased by overexpression of WT Avil or PLCE1, or by EGF stimulation; however, this increased PMR was ameliorated by inhibition of the ARP2/3 complex, indicating that ARP-dependent lamellipodia formation occurs downstream of AVIL and PLCE1 function. Together, these results delineate a comprehensive pathogenic axis of SRNS that integrates loss of AVIL function with alterations in the action of PLCE1, an established SRNS protein.Yale Center for Mendelian Genomics [U54HG006504]; NIHUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [DK076683]; Young Scholars Program of Children's Hospital of Fudan University; Basic Science Research Program through the National Research Foundation of Korea [2015R1D1A1A01056685]; DFG fellowships [VE 196/1-1, Jo 1324/1-1, HE 7456/1-1]; German National Academy of Sciences Leopoldina [LPDS-2015-07]; Egyptian Group for Orphan Renal Diseases (EGORD); Department of Science and Technology, Government of India (DST-SERB); National Institute of Diabetes and Digestive and Kidney DiseasesUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK) [DK-98120]; Public Health ServiceUnited States Public Health Service [DK-56338]We are grateful to the families and study participants for their contributions. We thank the Yale Center for Mendelian Genomics (U54HG006504) for WES analysis. FH is a William E. Harmon Professor of Pediatrics. This research was supported by the NIH (DK076683, to FH); the Young Scholars Program of Children's Hospital of Fudan University (to JR); Basic Science Research Program through the National Research Foundation of Korea 2015R1D1A1A01056685 (to HYG); DFG fellowships (VE 196/1-1, to ATvdV; Jo 1324/1-1, to TJS; and HE 7456/1-1, to TH); the German National Academy of Sciences Leopoldina (LPDS-2015-07, to EW); the Egyptian Group for Orphan Renal Diseases (EGORD) (to NAS); the Department of Science and Technology, Government of India (DST-SERB, to MAJ); the National Institute of Diabetes and Digestive and Kidney Diseases (DK-98120, to SK); and the Public Health Service (DK-56338, to SK)