@article {976, title = {Beyond the tubule: pathological variants of , encoding the megalin receptor, result in glomerular loss and early progressive chronic kidney disease.}, journal = {Am J Physiol Renal Physiol}, volume = {319}, year = {2020}, month = {2020 12 01}, pages = {F988-F999}, abstract = {

Pathogenic variants in the gene, encoding the multiligand receptor megalin, cause a rare autosomal recessive syndrome: Donnai-Barrow/Facio-Oculo-Acoustico-Renal (DB/FOAR) syndrome. Because of the rarity of the syndrome, the long-term consequences of the tubulopathy on human renal health have been difficult to ascertain, and the human clinical condition has hitherto been characterized as a benign tubular condition with asymptomatic low-molecular-weight proteinuria. We investigated renal function and morphology in a murine model of DB/FOAR syndrome and in patients with DB/FOAR. We analyzed glomerular filtration rate in mice by FITC-inulin clearance and clinically characterized six families, including nine patients with DB/FOAR and nine family members. Urine samples from patients were analyzed by Western blot analysis and biopsy materials were analyzed by histology. In the mouse model, we used histological methods to assess nephrogenesis and postnatal renal structure and contrast-enhanced magnetic resonance imaging to assess glomerular number. In megalin-deficient mice, we found a lower glomerular filtration rate and an increase in the abundance of injury markers, such as kidney injury molecule-1 and -acetyl-β-d-glucosaminidase. Renal injury was validated in patients, who presented with increased urinary kidney injury molecule-1, classical markers of chronic kidney disease, and glomerular proteinuria early in life. Megalin-deficient mice had normal nephrogenesis, but they had 19\% fewer nephrons in early adulthood and an increased fraction of nephrons with disconnected glomerulotubular junction. In conclusion, megalin dysfunction, as present in DB/FOAR syndrome, confers an increased risk of progression into chronic kidney disease.

}, keywords = {Adolescent, Adult, Animals, Child, Child, Preschool, Female, Genetic Predisposition to Disease, Genetic Variation, Humans, Kidney Glomerulus, Low Density Lipoprotein Receptor-Related Protein-2, Male, Mice, Mice, Knockout, Middle Aged, Renal Insufficiency, Chronic, Young Adult}, issn = {1522-1466}, doi = {10.1152/ajprenal.00295.2020}, author = {Charlton, Jennifer R and Tan, Weizhen and Daouk, Ghaleb and Teot, Lisa and Rosen, Seymour and Bennett, Kevin M and Cwiek, Aleksandra and Nam, Sejin and Emma, Francesco and Jouret, Fran{\c c}ois and Oliveira, Jo{\~a}o Paulo and Tranebj{\ae}rg, Lisbeth and Frykholm, Carina and Mane, Shrikant and Hildebrandt, Friedhelm and Srivastava, Tarak and Storm, Tina and Christensen, Erik Ils{\o} and Nielsen, Rikke} } @article {752, title = {Whole exome sequencing identified ATP6V1C2 as a novel candidate gene for recessive distal renal tubular acidosis.}, journal = {Kidney Int}, volume = {97}, year = {2020}, month = {2020 03}, pages = {567-579}, abstract = {

Distal renal tubular acidosis is a rare renal tubular disorder characterized by hyperchloremic metabolic acidosis and impaired urinary acidification. Mutations in three genes (ATP6V0A4, ATP6V1B1 and SLC4A1) constitute a monogenic causation in 58-70\% of familial cases of distal renal tubular acidosis. Recently, mutations in FOXI1 have been identified as an additional cause. Therefore, we hypothesized that further monogenic causes of distal renal tubular acidosis remain to be discovered. Panel sequencing and/or whole exome sequencing was performed in a cohort of 17 families with 19 affected individuals with pediatric onset distal renal tubular acidosis. A causative mutation was detected in one of the three "classical" known distal renal tubular acidosis genes in 10 of 17 families. The seven unsolved families were then subjected to candidate whole exome sequencing analysis. Potential disease causing mutations in three genes were detected: ATP6V1C2, which encodes another kidney specific subunit of the V-type proton ATPase (1 family); WDR72 (2 families), previously implicated in V-ATPase trafficking in cells; and SLC4A2 (1 family), a paralog of the known distal renal tubular acidosis gene SLC4A1. Two of these mutations were assessed for deleteriousness through functional studies. Yeast growth assays for ATP6V1C2 revealed loss-of-function for the patient mutation, strongly supporting ATP6V1C2 as a novel distal renal tubular acidosis gene. Thus, we provided a molecular diagnosis in a known distal renal tubular acidosis gene in 10 of 17 families (59\%) with this disease, identified mutations in ATP6V1C2 as a novel human candidate gene, and provided further evidence for phenotypic expansion in WDR72 mutations from amelogenesis imperfecta to distal renal tubular acidosis.

}, issn = {1523-1755}, doi = {10.1016/j.kint.2019.09.026}, author = {Jobst-Schwan, Tilman and Kl{\"a}mbt, Verena and Tarsio, Maureen and Heneghan, John F and Majmundar, Amar J and Shril, Shirlee and Buerger, Florian and Ottlewski, Isabel and Shmukler, Boris E and Topaloglu, Rezan and Hashmi, Seema and Hafeez, Farkhanda and Emma, Francesco and Greco, Marcella and Laube, Guido F and Fathy, Hanan M and Pohl, Martin and Gellermann, Jutta and Milosevic, Danko and Baum, Michelle A and Mane, Shrikant and Lifton, Richard P and Kane, Patricia M and Alper, Seth L and Hildebrandt, Friedhelm} } @article {159, title = {Functional genome-wide siRNA screen identifies KIAA0586 as mutated in Joubert syndrome.}, journal = {Elife}, volume = {4}, year = {2015}, month = {2015 May 30}, pages = {e06602}, abstract = {

Defective primary ciliogenesis or cilium stability forms the basis of human ciliopathies, including Joubert syndrome (JS), with defective cerebellar vermis development. We performed a high-content genome-wide small interfering RNA (siRNA) screen to identify genes regulating ciliogenesis as candidates for JS. We analyzed results with a supervised-learning approach, using SYSCILIA gold standard, Cildb3.0, a centriole siRNA screen and the GTex project, identifying 591 likely candidates. Intersection of this data with whole exome results from 145 individuals with unexplained JS identified six families with predominantly compound heterozygous mutations in KIAA0586. A c.428del base deletion in 0.1\% of the general population was found in trans with a second mutation in an additional set of 9 of 163 unexplained JS patients. KIAA0586 is an orthologue of chick Talpid3, required for ciliogenesis and Sonic hedgehog signaling. Our results uncover a relatively high frequency cause for JS and contribute a list of candidates for future gene discoveries in ciliopathies.

}, keywords = {Abnormalities, Multiple, Cell Cycle Proteins, Cerebellum, Eye Abnormalities, Gene Frequency, Genetic Predisposition to Disease, Genetic Testing, Genome-Wide Association Study, Heterozygote, Humans, Kidney Diseases, Cystic, Mutant Proteins, Retina, RNA, Small Interfering}, issn = {2050-084X}, doi = {10.7554/eLife.06602}, author = {Roosing, Susanne and Hofree, Matan and Kim, Sehyun and Scott, Eric and Copeland, Brett and Romani, Marta and Silhavy, Jennifer L and Rosti, Rasim O and Schroth, Jana and Mazza, Tommaso and Miccinilli, Elide and Zaki, Maha S and Swoboda, Kathryn J and Milisa-Drautz, Joanne and Dobyns, William B and Mikati, Mohamed A and {\.I}ncecik, Faruk and Azam, Matloob and Borgatti, Renato and Romaniello, Romina and Boustany, Rose-Mary and Clericuzio, Carol L and D{\textquoteright}Arrigo, Stefano and Str{\o}mme, Petter and Boltshauser, Eugen and Stanzial, Franco and Mirabelli-Badenier, Marisol and Moroni, Isabella and Bertini, Enrico and Emma, Francesco and Steinlin, Maja and Hildebrandt, Friedhelm and Johnson, Colin A and Freilinger, Michael and Vaux, Keith K and Gabriel, Stacey B and Aza-Blanc, Pedro and Heynen-Genel, Susanne and Ideker, Trey and Dynlacht, Brian D and Lee, Ji Eun and Valente, Enza Maria and Kim, Joon and Gleeson, Joseph G} }