@article {991, title = {Mutations in transcription factor CP2-like 1 may cause a novel syndrome with distal renal tubulopathy in humans.}, journal = {Nephrol Dial Transplant}, volume = {36}, year = {2021}, month = {2021 01 25}, pages = {237-246}, abstract = {

BACKGROUND: An underlying monogenic cause of early-onset chronic kidney disease (CKD) can be detected in \~{}20\% of individuals. For many etiologies of CKD manifesting before 25 years of age, >200 monogenic causative genes have been identified to date, leading to the elucidation of mechanisms of renal pathogenesis.

METHODS: In 51 families with echogenic kidneys and CKD, we performed whole-exome sequencing to identify novel monogenic causes of CKD.

RESULTS: We discovered a homozygous truncating mutation in the transcription factor gene transcription factor CP2-like 1 (TFCP2L1) in an Arabic patient of consanguineous descent. The patient developed CKD by the age of 2 months and had episodes of severe hypochloremic, hyponatremic and hypokalemic alkalosis, seizures, developmental delay and hypotonia together with cataracts. We found that TFCP2L1~was localized throughout kidney development particularly in the distal nephron. Interestingly, TFCP2L1 induced the growth and development of renal tubules from rat mesenchymal cells. Conversely, the deletion of TFCP2L1~in mice was previously shown to lead to reduced expression of renal cell markers including ion transporters and cell identity proteins expressed in different segments of the distal nephron. TFCP2L1 localized to the nucleus in HEK293T cells only upon coexpression with its paralog upstream-binding protein 1 (UBP1). A TFCP2L1 mutant complementary DNA (cDNA) clone that represented the patient{\textquoteright}s mutation failed to form homo- and heterodimers with UBP1, an essential step for its transcriptional activity.

CONCLUSION: Here, we identified a loss-of-function TFCP2L1 mutation as a potential novel cause of CKD in childhood accompanied by a salt-losing tubulopathy.

}, keywords = {Animals, Child, DNA-Binding Proteins, Epithelial-Mesenchymal Transition, Female, HEK293 Cells, Humans, Kidney Diseases, Mice, Mice, Knockout, Mutation, Rats, Repressor Proteins, Single-Cell Analysis, Transcription Factors, Whole Exome Sequencing}, issn = {1460-2385}, doi = {10.1093/ndt/gfaa215}, author = {Kl{\"a}mbt, Verena and Werth, Max and Onuchic-Whitford, Ana C and Getwan, Maike and Kitzler, Thomas M and Buerger, Florian and Mao, Youying and Deutsch, Konstantin and Mann, Nina and Majmundar, Amar J and Kaminski, Michael M and Shen, Tian and Schmidt-Ott, Kai M and Shalaby, Mohamed and El Desoky, Sherif and Kari, Jameela A and Shril, Shirlee and Lienkamp, Soeren S and Barasch, Jonathan and Hildebrandt, Friedhelm} } @article {977, title = {Phenotype expansion of heterozygous FOXC1 pathogenic variants toward involvement of congenital anomalies of the kidneys and urinary tract (CAKUT).}, journal = {Genet Med}, volume = {22}, year = {2020}, month = {2020 10}, pages = {1673-1681}, abstract = {

PURPOSE: Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common cause of chronic kidney disease in childhood and adolescence. We aim to identify novel monogenic causes of CAKUT.

METHODS: Exome sequencing was performed in 550 CAKUT-affected families.

RESULTS: We discovered seven FOXC1 heterozygous likely pathogenic variants within eight CAKUT families. These variants are either never reported, or present in <5 alleles in the gnomAD database with ~141,456 controls. FOXC1 is a causal gene for Axenfeld-Rieger syndrome type 3 and anterior segment dysgenesis 3. Pathogenic variants in FOXC1 have not been detected in patients with CAKUT yet. Interestingly, mouse models for Foxc1 show severe CAKUT phenotypes with incomplete penetrance and variable expressivity. The FOXC1 variants are enriched in the CAKUT cohort compared with the control. Genotype-phenotype correlations showed that Axenfeld-Rieger syndrome or anterior segment dysgenesis can be caused by both truncating and missense pathogenic variants, and the missense variants are located at the forkhead domain. In contrast, for CAKUT, there is no truncating pathogenic variant, and all variants except one are located outside the forkhead domain.

CONCLUSION: We thereby expanded the phenotype of FOXC1 pathogenic variants toward involvement of CAKUT, which can potentially be explained by allelism.

}, keywords = {Child, Eye Abnormalities, Forkhead Transcription Factors, Heterozygote, Humans, Kidney, Phenotype, Urinary Tract}, issn = {1530-0366}, doi = {10.1038/s41436-020-0844-z}, author = {Wu, Chen-Han Wilfred and Mann, Nina and Nakayama, Makiko and Connaughton, Dervla M and Dai, Rufeng and Kolvenbach, Caroline M and Kause, Franziska and Ottlewski, Isabel and Wang, Chunyan and Kl{\"a}mbt, Verena and Seltzsam, Steve and Lai, Ethan W and Selvin, Aravind and Senguttuva, Prabha and Bodamer, Olaf and Stein, Deborah R and El Desoky, Sherif and Kari, Jameela A and Tasic, Velibor and Bauer, Stuart B and Shril, Shirlee and Hildebrandt, Friedhelm} } @article {587, title = {Genetic variants in the LAMA5 gene in pediatric nephrotic syndrome.}, journal = {Nephrol Dial Transplant}, volume = {34}, year = {2019}, month = {2019 03 01}, pages = {485-493}, abstract = {

BACKGROUND: 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.

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.

}, issn = {1460-2385}, doi = {10.1093/ndt/gfy028}, author = {Braun, Daniela A and Warejko, Jillian K and Ashraf, Shazia and Tan, Weizhen and Daga, Ankana and Schneider, Ronen and Hermle, Tobias and Jobst-Schwan, Tilman and Widmeier, Eugen and Majmundar, Amar J and Nakayama, Makiko and Schapiro, David and Rao, Jia and Schmidt, Johanna Magdalena and Hoogstraten, Charlotte A and Hugo, Hannah and Bakkaloglu, Sevcan A and Kari, Jameela A and El Desoky, Sherif and Daouk, Ghaleb and Mane, Shrikant and Lifton, Richard P and Shril, Shirlee and Hildebrandt, Friedhelm} } @article {502, title = { and Mutations Implicate RAB5 Regulation in Nephrotic Syndrome.}, journal = {J Am Soc Nephrol}, volume = {29}, year = {2018}, month = {2018 Aug}, pages = {2123-2138}, abstract = {

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 functional significance of two genes and the mutations therein that we discovered through this sequencing and conducted complementary studies in podocyte-like nephrocytes.

RESULTS: We identified conserved, homozygous missense mutations of in two families with early-onset NS and a homozygous missense mutation of in two siblings with SRNS. GAPVD1 and ANKFY1 interact with the endosomal regulator RAB5. Coimmunoprecipitation assays indicated interaction between GAPVD1 and ANKFY1 proteins, which also colocalized when expressed in HEK293T cells. Silencing either protein diminished the podocyte migration rate. Compared with wild-type GAPVD1 and ANKFY1, the mutated proteins produced upon ectopic expression of or bearing the patient-derived mutations exhibited altered binding affinity for active RAB5 and reduced ability to rescue the knockout-induced defect in podocyte migration. Coimmunoprecipitation assays further demonstrated a physical interaction between nephrin and GAPVD1, and immunofluorescence revealed partial colocalization of these proteins in rat glomeruli. The patient-derived mutations reduced nephrin-GAPVD1 binding affinity. In , silencing impaired endocytosis and caused mistrafficking of the nephrin ortholog.

CONCLUSIONS: Mutations in and probably in are novel monogenic causes of NS. The discovery of these genes implicates RAB5 regulation in the pathogenesis of human NS.

}, issn = {1533-3450}, doi = {10.1681/ASN.2017121312}, author = {Hermle, Tobias and Schneider, Ronen and Schapiro, David and Braun, Daniela A and van der Ven, Amelie T and Warejko, Jillian K and Daga, Ankana and Widmeier, Eugen and Nakayama, Makiko and Jobst-Schwan, Tilman and Majmundar, Amar J and Ashraf, Shazia and Rao, Jia and Finn, Laura S and Tasic, Velibor and Hernandez, Joel D and Bagga, Arvind and Jalalah, Sawsan M and El Desoky, Sherif and Kari, Jameela A and Laricchia, Kristen M and Lek, Monkol and Rehm, Heidi L and MacArthur, Daniel G and Mane, Shrikant and Lifton, Richard P and Shril, Shirlee and Hildebrandt, Friedhelm} } @article {630, title = {Whole Exome Sequencing of Patients with Steroid-Resistant Nephrotic Syndrome.}, journal = {Clin J Am Soc Nephrol}, volume = {13}, year = {2018}, month = {2018 01 06}, pages = {53-62}, abstract = {

BACKGROUND AND OBJECTIVES: Steroid-resistant nephrotic syndrome overwhelmingly progresses to ESRD. More than 30 monogenic genes have been identified to cause steroid-resistant nephrotic syndrome. We previously detected causative mutations using targeted panel sequencing in 30\% of patients with steroid-resistant nephrotic syndrome. Panel sequencing has a number of limitations when compared with whole exome sequencing. We employed whole exome sequencing to detect monogenic causes of steroid-resistant nephrotic syndrome in an international cohort of 300 families.

DESIGN, SETTING, PARTICIPANTS, \& MEASUREMENTS: Three hundred thirty-five individuals with steroid-resistant nephrotic syndrome from 300 families were recruited from April of 1998 to June of 2016. Age of onset was restricted to <25 years of age. Exome data were evaluated for 33 known monogenic steroid-resistant nephrotic syndrome genes.

RESULTS: In 74 of 300 families (25\%), we identified a causative mutation in one of 20 genes known to cause steroid-resistant nephrotic syndrome. In 11 families (3.7\%), we detected a mutation in a gene that causes a phenocopy of steroid-resistant nephrotic syndrome. This is consistent with our previously published identification of mutations using a panel approach. We detected a causative mutation in a known steroid-resistant nephrotic syndrome gene in 38\% of consanguineous families and in 13\% of nonconsanguineous families, and 48\% of children with congenital nephrotic syndrome. A total of 68 different mutations were detected in 20 of 33 steroid-resistant nephrotic syndrome genes. Fifteen of these mutations were novel. , , , and were the most common genes in which we detected a mutation. In another 28\% of families, we detected mutations in one or more candidate genes for steroid-resistant nephrotic syndrome.

CONCLUSIONS: Whole exome sequencing is a sensitive approach toward diagnosis of monogenic causes of steroid-resistant nephrotic syndrome. A molecular genetic diagnosis of steroid-resistant nephrotic syndrome may have important consequences for the management of treatment and kidney transplantation in steroid-resistant nephrotic syndrome.

}, issn = {1555-905X}, doi = {10.2215/CJN.04120417}, author = {Warejko, Jillian K and Tan, Weizhen and Daga, Ankana and Schapiro, David and Lawson, Jennifer A and Shril, Shirlee and Lovric, Svjetlana and Ashraf, Shazia and Rao, Jia and Hermle, Tobias and Jobst-Schwan, Tilman and Widmeier, Eugen and Majmundar, Amar J and Schneider, Ronen and Gee, Heon Yung and Schmidt, J Magdalena and Vivante, Asaf and van der Ven, Amelie T and Ityel, Hadas and Chen, Jing and Sadowski, Carolin E and Kohl, Stefan and Pabst, Werner L and Nakayama, Makiko and Somers, Michael J G and Rodig, Nancy M and Daouk, Ghaleb and Baum, Michelle and Stein, Deborah R and Ferguson, Michael A and Traum, Avram Z and Soliman, Neveen A and Kari, Jameela A and El Desoky, Sherif and Fathy, Hanan and Zenker, Martin and Bakkaloglu, Sevcan A and M{\"u}ller, Dominik and Noyan, Aytul and Ozaltin, Fatih and Cadnapaphornchai, Melissa A and Hashmi, Seema and Hopcian, Jeffrey and Kopp, Jeffrey B and Benador, Nadine and Bockenhauer, Detlef and Bogdanovic, Radovan and Staji{\'c}, Natasa and Chernin, Gil and Ettenger, Robert and Fehrenbach, Henry and Kemper, Markus and Munarriz, Reyner Loza and Podracka, Ludmila and B{\"u}scher, Rainer and Serdaroglu, Erkin and Tasic, Velibor and Mane, Shrikant and Lifton, Richard P and Braun, Daniela A and Hildebrandt, Friedhelm} } @article {516, title = {Whole-Exome Sequencing Identifies Causative Mutations in Families with Congenital Anomalies of the Kidney and Urinary Tract.}, journal = {J Am Soc Nephrol}, volume = {29}, year = {2018}, month = {2018 Sep}, pages = {2348-2361}, abstract = {

BACKGROUND: Congenital anomalies of the kidney and urinary tract (CAKUT) are the most prevalent cause of kidney disease in the first three decades of life. Previous gene panel studies showed monogenic causation in up to 12\% of patients with CAKUT.

METHODS: We applied whole-exome sequencing to analyze the genotypes of individuals from 232 families with CAKUT, evaluating for mutations in single genes known to cause human CAKUT and genes known to cause CAKUT in mice. In consanguineous or multiplex families, we additionally performed a search for novel monogenic causes of CAKUT.

RESULTS: In 29 families (13\%), we detected a causative mutation in a known gene for isolated or syndromic CAKUT that sufficiently explained the patient{\textquoteright}s CAKUT phenotype. In three families (1\%), we detected a mutation in a gene reported to cause a phenocopy of CAKUT. In 15 of 155 families with isolated CAKUT, we detected deleterious mutations in syndromic CAKUT genes. Our additional search for novel monogenic causes of CAKUT in consanguineous and multiplex families revealed a potential single, novel monogenic CAKUT gene in 19 of 232 families (8\%).

CONCLUSIONS: We identified monogenic mutations in a known human CAKUT gene or CAKUT phenocopy gene as the cause of disease in 14\% of the CAKUT families in this study. Whole-exome sequencing provides an etiologic diagnosis in a high fraction of patients with CAKUT and will provide a new basis for the mechanistic understanding of CAKUT.

}, issn = {1533-3450}, doi = {10.1681/ASN.2017121265}, author = {van der Ven, Amelie T and Connaughton, Dervla M and Ityel, Hadas and Mann, Nina and Nakayama, Makiko and Chen, Jing and Vivante, Asaf and Hwang, Daw-Yang and Schulz, Julian and Braun, Daniela A and Schmidt, Johanna Magdalena and Schapiro, David and Schneider, Ronen and Warejko, Jillian K and Daga, Ankana and Majmundar, Amar J and Tan, Weizhen and Jobst-Schwan, Tilman and Hermle, Tobias and Widmeier, Eugen and Ashraf, Shazia and Amar, Ali and Hoogstraaten, Charlotte A and Hugo, Hannah and Kitzler, Thomas M and Kause, Franziska and Kolvenbach, Caroline M and Dai, Rufeng and Spaneas, Leslie and Amann, Kassaundra and Stein, Deborah R and Baum, Michelle A and Somers, Michael J G and Rodig, Nancy M and Ferguson, Michael A and Traum, Avram Z and Daouk, Ghaleb H and Bogdanovic, Radovan and Staji{\'c}, Natasa and Soliman, Neveen A and Kari, Jameela A and El Desoky, Sherif and Fathy, Hanan M and Milosevic, Danko and Al-Saffar, Muna and Awad, Hazem S and Eid, Loai A and Selvin, Aravind and Senguttuvan, Prabha and Sanna-Cherchi, Simone and Rehm, Heidi L and MacArthur, Daniel G and Lek, Monkol and Laricchia, Kristen M and Wilson, Michael W and Mane, Shrikant M and Lifton, Richard P and Lee, Richard S and Bauer, Stuart B and Lu, Weining and Reutter, Heiko M and Tasic, Velibor and Shril, Shirlee and Hildebrandt, Friedhelm} } @article {457, title = {Advillin acts upstream of phospholipase C ϵ1 in steroid-resistant nephrotic syndrome.}, journal = {J Clin Invest}, volume = {127}, year = {2017}, month = {2017 12 01}, pages = {4257-4269}, abstract = {

Steroid-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.

}, keywords = {Actin-Related Protein 2-3 Complex, Cell Movement, Diglycerides, Female, Humans, Male, Microfilament Proteins, Mutation, Nephrotic Syndrome, Phosphoinositide Phospholipase C, Podocytes, Pseudopodia}, issn = {1558-8238}, doi = {10.1172/JCI94138}, author = {Rao, Jia and Ashraf, Shazia and Tan, Weizhen and van der Ven, Amelie T and Gee, Heon Yung and Braun, Daniela A and Feh{\'e}r, Krisztina and George, Sudeep P and Esmaeilniakooshkghazi, Amin and Choi, Won-Il and Jobst-Schwan, Tilman and Schneider, Ronen and Schmidt, Johanna Magdalena and Widmeier, Eugen and Warejko, Jillian K and Hermle, Tobias and Schapiro, David and Lovric, Svjetlana and Shril, Shirlee and Daga, Ankana and Nayir, Ahmet and Shenoy, Mohan and Tse, Yincent and Bald, Martin and Helmchen, Udo and Mir, Sevgi and Berdeli, Afig and Kari, Jameela A and El Desoky, Sherif and Soliman, Neveen A and Bagga, Arvind and Mane, Shrikant and Jairajpuri, Mohamad A and Lifton, Richard P and Khurana, Seema and Martins, Jose C and Hildebrandt, Friedhelm} } @article {282, title = {ADCK4 mutations promote steroid-resistant nephrotic syndrome through CoQ10 biosynthesis disruption.}, journal = {J Clin Invest}, volume = {123}, year = {2013}, month = {2013 Dec}, pages = {5179-89}, abstract = {

Identification of single-gene causes of steroid-resistant nephrotic syndrome (SRNS) has furthered the understanding of the pathogenesis of this disease. Here, using a combination of homozygosity mapping and whole human exome resequencing, we identified mutations in the aarF domain containing kinase 4 (ADCK4) gene in 15 individuals with SRNS from 8 unrelated families. ADCK4 was highly similar to ADCK3, which has been shown to participate in coenzyme Q10 (CoQ10) biosynthesis. Mutations in ADCK4 resulted in reduced CoQ10 levels and reduced mitochondrial respiratory enzyme activity in cells isolated from individuals with SRNS and transformed lymphoblasts. Knockdown of adck4 in zebrafish and Drosophila recapitulated nephrotic syndrome-associated phenotypes. Furthermore, ADCK4 was expressed in glomerular podocytes and partially localized to podocyte mitochondria and foot processes in rat kidneys and cultured human podocytes. In human podocytes, ADCK4 interacted with members of the CoQ10 biosynthesis pathway, including COQ6, which has been linked with SRNS and COQ7. Knockdown of ADCK4 in podocytes resulted in decreased migration, which was reversed by CoQ10 addition. Interestingly, a patient with SRNS with a homozygous ADCK4 frameshift mutation had partial remission following CoQ10 treatment. These data indicate that individuals with SRNS with mutations in ADCK4 or other genes that participate in CoQ10 biosynthesis may be treatable with CoQ10.

}, keywords = {Adolescent, Adrenal Cortex Hormones, Amino Acid Sequence, Animals, Cells, Cultured, Child, Consanguinity, Conserved Sequence, Disease Models, Animal, DNA Mutational Analysis, Drosophila Proteins, Drug Resistance, Exome, Fibroblasts, Gene Knockdown Techniques, Humans, Mitochondria, Molecular Sequence Data, Mutation, Nephrotic Syndrome, Podocytes, Protein Kinases, Rats, Sequence Alignment, Sequence Homology, Amino Acid, Ubiquinone, Young Adult, Zebrafish, Zebrafish Proteins}, issn = {1558-8238}, doi = {10.1172/JCI69000}, author = {Ashraf, Shazia and Gee, Heon Yung and Woerner, Stephanie and Xie, Letian X and Vega-Warner, Virginia and Lovric, Svjetlana and Fang, Humphrey and Song, Xuewen and Cattran, Daniel C and Avila-Casado, Carmen and Paterson, Andrew D and Nitschk{\'e}, Patrick and Bole-Feysot, Christine and Cochat, Pierre and Esteve-Rudd, Julian and Haberberger, Birgit and Allen, Susan J and Zhou, Weibin and Airik, Rannar and Otto, Edgar A and Barua, Moumita and Al-Hamed, Mohamed H and Kari, Jameela A and Evans, Jonathan and Bierzynska, Agnieszka and Saleem, Moin A and Bockenhauer, Detlef and Kleta, Robert and El Desoky, Sherif and Hacihamdioglu, Duygu O and Gok, Faysal and Washburn, Joseph and Wiggins, Roger C and Choi, Murim and Lifton, Richard P and Levy, Shawn and Han, Zhe and Salviati, Leonardo and Prokisch, Holger and Williams, David S and Pollak, Martin and Clarke, Catherine F and Pei, York and Antignac, Corinne and Hildebrandt, Friedhelm} }