@article {1007, title = {De novo TRIM8 variants impair its protein localization to nuclear bodies and cause developmental delay, epilepsy, and focal segmental glomerulosclerosis.}, journal = {Am J Hum Genet}, volume = {108}, year = {2021}, month = {2021 02 04}, pages = {357-367}, abstract = {

Focal segmental glomerulosclerosis (FSGS) is the main pathology underlying steroid-resistant nephrotic syndrome (SRNS) and a leading cause of chronic kidney disease. Monogenic forms of pediatric SRNS are predominantly caused by recessive mutations, while the contribution of de novo variants (DNVs) to this trait is poorly understood. Using exome sequencing (ES) in a proband with FSGS/SRNS, developmental delay, and epilepsy, we discovered a nonsense DNV in TRIM8, which encodes the E3 ubiquitin ligase tripartite motif containing 8. To establish whether TRIM8 variants represent a cause of FSGS, we aggregated exome/genome-sequencing data for 2,501 pediatric FSGS/SRNS-affected individuals and 48,556 control subjects, detecting eight heterozygous TRIM8 truncating variants in affected subjects but none in control subjects (p = 3.28~{\texttimes} 10). In all six cases with available parental DNA, we demonstrated de novo inheritance (p~=~2.21~{\texttimes} 10). Reverse phenotyping revealed neurodevelopmental disease in all eight families. We next analyzed ES from 9,067 individuals with epilepsy, yielding three additional families with truncating TRIM8 variants. Clinical review revealed FSGS in all. All TRIM8 variants cause protein truncation clustering within the last exon between residues 390 and 487 of the 551 amino acid protein, indicating a correlation between this syndrome and loss of the TRIM8 C-terminal region. Wild-type TRIM8 overexpressed in immortalized human podocytes and neuronal cells localized to nuclear bodies, while constructs harboring patient-specific variants mislocalized diffusely to the nucleoplasm. Co-localization studies demonstrated that Gemini and Cajal bodies frequently abut a TRIM8 nuclear body. Truncating TRIM8 DNVs cause a neuro-renal syndrome via aberrant TRIM8 localization, implicating nuclear bodies in FSGS and developmental brain disease.

}, keywords = {Adult, Animals, Carrier Proteins, Cell Line, Child, Child, Preschool, Codon, Nonsense, Developmental Disabilities, Epilepsy, Female, Glomerulosclerosis, Focal Segmental, Humans, Intranuclear Space, Kidney, Male, Mice, Mutation, Nephrotic Syndrome, Nerve Tissue Proteins, Phenotype, Podocytes, Whole Exome Sequencing}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2021.01.008}, author = {Weng, Patricia L and Majmundar, Amar J and Khan, Kamal and Lim, Tze Y and Shril, Shirlee and Jin, Gina and Musgrove, John and Wang, Minxian and Ahram, Dina F and Aggarwal, Vimla S and Bier, Louise E and Heinzen, Erin L and Onuchic-Whitford, Ana C and Mann, Nina and Buerger, Florian and Schneider, Ronen and Deutsch, Konstantin and Kitzler, Thomas M and Kl{\"a}mbt, Verena and Kolb, Amy and Mao, Youying and Moufawad El Achkar, Christelle and Mitrotti, Adele and Martino, Jeremiah and Beck, Bodo B and Altm{\"u}ller, Janine and Benz, Marcus R and Yano, Shoji and Mikati, Mohamad A and Gunduz, Talha and Cope, Heidi and Shashi, Vandana and Trachtman, Howard and Bodria, Monica and Caridi, Gianluca and Pisani, Isabella and Fiaccadori, Enrico and AbuMaziad, Asmaa S and Martinez-Agosto, Julian A and Yadin, Ora and Zuckerman, Jonathan and Kim, Arang and John-Kroegel, Ulrike and Tyndall, Amanda V and Parboosingh, Jillian S and Innes, A Micheil and Bierzynska, Agnieszka and Koziell, Ania B and Muorah, Mordi and Saleem, Moin A and Hoefele, Julia and Riedhammer, Korbinian M and Gharavi, Ali G and Jobanputra, Vaidehi and Pierce-Hoffman, Emma and Seaby, Eleanor G and O{\textquoteright}Donnell-Luria, Anne and Rehm, Heidi L and Mane, Shrikant and D{\textquoteright}Agati, Vivette D and Pollak, Martin R and Ghiggeri, Gian Marco and Lifton, Richard P and Goldstein, David B and Davis, Erica E and Hildebrandt, Friedhelm and Sanna-Cherchi, Simone} } @article {919, title = {DAAM2 Variants Cause Nephrotic Syndrome via Actin Dysregulation.}, journal = {Am J Hum Genet}, volume = {107}, year = {2020}, month = {2020 12 03}, pages = {1113-1128}, abstract = {

The discovery of >60 monogenic causes of nephrotic syndrome (NS) has revealed a central role for the actin regulators RhoA/Rac1/Cdc42 and their effectors, including the formin INF2. By whole-exome sequencing (WES), we here discovered bi-allelic variants in the formin DAAM2 in four unrelated families with steroid-resistant NS. We show that DAAM2 localizes to the cytoplasm in podocytes and in kidney sections. Further, the variants impair DAAM2-dependent actin remodeling processes: wild-type DAAM2 cDNA, but not cDNA representing missense variants found in individuals with NS, rescued reduced podocyte migration rate (PMR) and restored reduced filopodia formation in shRNA-induced DAAM2-knockdown podocytes. Filopodia restoration was also induced by the formin-activating molecule IMM-01. DAAM2 also co-localizes and co-immunoprecipitates with INF2, which is intriguing since variants in both formins cause NS. Using in~vitro bulk and TIRF microscopy assays, we find that DAAM2 variants alter actin assembly activities of the formin. In a Xenopus daam2-CRISPR knockout model, we demonstrate actin dysregulation in~vivo and glomerular maldevelopment that is rescued by WT-DAAM2 mRNA. We conclude that DAAM2 variants are a likely cause of monogenic human SRNS due to actin dysregulation in podocytes. Further, we provide evidence that DAAM2-associated SRNS may be amenable to treatment using actin regulating compounds.

}, keywords = {Actins, Alleles, Animals, Animals, Genetically Modified, Cell Movement, Cytoplasm, Formins, Genetic Variation, Humans, Kidney, Kidney Glomerulus, Microfilament Proteins, Mutation, Missense, Nephrotic Syndrome, Podocytes, Pseudopodia, rho GTP-Binding Proteins, RNA, Small Interfering, Whole Exome Sequencing, Xenopus}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2020.11.008}, author = {Schneider, Ronen and Deutsch, Konstantin and Hoeprich, Gregory J and Marquez, Jonathan and Hermle, Tobias and Braun, Daniela A and Seltzsam, Steve and Kitzler, Thomas M and Mao, Youying and Buerger, Florian and Majmundar, Amar J and Onuchic-Whitford, Ana C and Kolvenbach, Caroline M and Schierbaum, Luca and Schneider, Sophia and Halawi, Abdul A and Nakayama, Makiko and Mann, Nina and Connaughton, Dervla M and Kl{\"a}mbt, Verena and Wagner, Matias and Riedhammer, Korbinian M and Renders, Lutz and Katsura, Yoshichika and Thumkeo, Dean and Soliman, Neveen A and Mane, Shrikant and Lifton, Richard P and Shril, Shirlee and Khokha, Mustafa K and Hoefele, Julia and Goode, Bruce L and Hildebrandt, Friedhelm} } @article {703, title = {COL4A1 mutations as a potential novel cause of autosomal dominant CAKUT in humans.}, journal = {Hum Genet}, volume = {138}, year = {2019}, month = {2019 Oct}, pages = {1105-1115}, abstract = {

Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common cause of chronic kidney disease (~ 45\%) that manifests before 30~years of age. The genetic locus containing COL4A1 (13q33-34) has been implicated in vesicoureteral reflux (VUR), but mutations in COL4A1 have not been reported in CAKUT. We hypothesized that COL4A1 mutations cause CAKUT in humans. We performed whole exome sequencing (WES) in 550 families with CAKUT. As negative control cohorts we used WES sequencing data from patients with nephronophthisis (NPHP) with no genetic cause identified (n = 257) and with nephrotic syndrome (NS) due to monogenic causes (n = 100). We identified a not previously reported heterozygous missense variant in COL4A1 in three siblings with isolated VUR. When examining 549 families with CAKUT, we identified nine additional different heterozygous missense mutations in COL4A1 in 11 individuals from 11 unrelated families with CAKUT, while no COL4A1 mutations were identified in a control cohort with NPHP and only one in the cohort with NS. Most individuals (12/14) had isolated CAKUT with no extrarenal features. The predominant phenotype was VUR (9/14). There were no clinical features of the COL4A1-related disorders (e.g., HANAC syndrome, porencephaly, tortuosity of retinal arteries). Whereas COL4A1-related disorders are typically caused by glycine substitutions in the collagenous domain (84.4\% of variants), only one variant in our cohort is a glycine substitution within the collagenous domain (1/10). We identified heterozygous COL4A1 mutations as a potential novel autosomal dominant cause of CAKUT that is allelic to the established COL4A1-related disorders and predominantly caused by non-glycine substitutions.

}, keywords = {Alleles, Amino Acid Substitution, Collagen Type IV, Computational Biology, Congenital Abnormalities, Databases, Genetic, DNA Mutational Analysis, Evolution, Molecular, Female, Genetic Association Studies, Genetic Loci, Genomics, Heterozygote, Humans, Kidney, Kidney Diseases, Cystic, Male, Mutation, Nephrotic Syndrome, Phenotype, Urinary Tract, Web Browser, Whole Exome Sequencing}, issn = {1432-1203}, doi = {10.1007/s00439-019-02042-4}, author = {Kitzler, Thomas M and Schneider, Ronen and Kohl, Stefan and Kolvenbach, Caroline M and Connaughton, Dervla M and Dai, Rufeng and Mann, Nina and Nakayama, Makiko and Majmundar, Amar J and Wu, Chen-Han W and Kari, Jameela A and El Desoky, Sherif M and Senguttuvan, Prabha and Bogdanovic, Radovan and Staji{\'c}, Natasa and Valivullah, Zaheer and Lek, Monkol and Mane, Shrikant and Lifton, Richard P and Tasic, Velibor and Shril, Shirlee and Hildebrandt, Friedhelm} }