@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 {928, title = {Novel congenital disorder of O-linked glycosylation caused by GALNT2 loss of function.}, journal = {Brain}, volume = {143}, year = {2020}, month = {2020 04 01}, pages = {1114-1126}, abstract = {

Congenital disorders of glycosylation are a growing group of rare genetic disorders caused by deficient protein and lipid glycosylation. Here, we report the clinical, biochemical, and molecular features of seven patients from four families with GALNT2-congenital disorder of glycosylation (GALNT2-CDG), an O-linked glycosylation disorder. GALNT2 encodes the Golgi-localized polypeptide N-acetyl-d-galactosamine-transferase 2 isoenzyme. GALNT2 is widely expressed in most cell types and directs initiation of mucin-type protein O-glycosylation. All patients showed loss of O-glycosylation of apolipoprotein C-III, a non-redundant substrate for GALNT2. Patients with GALNT2-CDG generally exhibit a syndrome characterized by global developmental delay, intellectual disability with language deficit, autistic features, behavioural abnormalities, epilepsy, chronic insomnia, white matter changes on brain MRI, dysmorphic features, decreased stature, and decreased high density lipoprotein cholesterol levels. Rodent (mouse and rat) models of GALNT2-CDG recapitulated much of the human phenotype, including poor growth and neurodevelopmental abnormalities. In behavioural studies, GALNT2-CDG mice demonstrated cerebellar motor deficits, decreased sociability, and impaired sensory integration and processing. The multisystem nature of phenotypes in patients and rodent models of GALNT2-CDG suggest that there are multiple non-redundant protein substrates of GALNT2 in various tissues, including brain, which are critical to normal growth and development.

}, keywords = {Adolescent, Animals, Apolipoprotein C-III, Child, Child, Preschool, Developmental Disabilities, Female, Glycosylation, Humans, Loss of Function Mutation, Male, Mice, N-Acetylgalactosaminyltransferases, Pedigree, Rats, Young Adult}, issn = {1460-2156}, doi = {10.1093/brain/awaa063}, author = {Zilmer, Monica and Edmondson, Andrew C and Khetarpal, Sumeet A and Alesi, Viola and Zaki, MAH S and Rostasy, Kevin and Madsen, Camilla G and Lepri, Francesca R and Sinibaldi, Lorenzo and Cusmai, Raffaella and Novelli, Antonio and Issa, Mahmoud Y and Fenger, Christina D and Abou Jamra, Rami and Reutter, Heiko and Briuglia, Silvana and Agolini, Emanuele and Hansen, Lars and Pet{\"a}j{\"a}-Repo, Ulla E and Hintze, John and Raymond, Kimiyo M and Liedtke, Kristen and Stanley, Valentina and Musaev, Damir and Gleeson, Joseph G and Vitali, Cecilia and O{\textquoteright}Brien, W Timothy and Gardella, Elena and Rubboli, Guido and Rader, Daniel J and Schjoldager, Katrine T and M{\o}ller, Rikke S} } @article {437, title = {Asprosin is a centrally acting orexigenic hormone.}, journal = {Nat Med}, volume = {23}, year = {2017}, month = {2017 Dec}, pages = {1444-1453}, abstract = {

Asprosin is a recently discovered fasting-induced hormone that promotes hepatic glucose production. Here we demonstrate that asprosin in the circulation crosses the blood-brain barrier and directly activates orexigenic AgRP neurons via a cAMP-dependent pathway. This signaling results in inhibition of downstream anorexigenic proopiomelanocortin (POMC)-positive neurons in a GABA-dependent manner, which then leads to appetite stimulation and a drive to accumulate adiposity and body weight. In humans, a genetic deficiency in asprosin causes a syndrome characterized by low appetite and extreme leanness; this is phenocopied by mice carrying similar mutations and can be fully rescued by asprosin. Furthermore, we found that obese humans and mice had pathologically elevated concentrations of circulating asprosin, and neutralization of asprosin in the blood with a monoclonal antibody reduced appetite and body weight in obese mice, in addition to improving their glycemic profile. Thus, in addition to performing a glucogenic function, asprosin is a centrally acting orexigenic hormone that is a potential therapeutic target in the treatment of both obesity and diabetes.

}, keywords = {Adolescent, Adult, Animals, Appetite Depressants, Appetite Regulation, Female, Humans, Hypothalamus, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Microfilament Proteins, Neurons, Peptide Fragments, Peptide Hormones, Rats, Signal Transduction, Young Adult}, issn = {1546-170X}, doi = {10.1038/nm.4432}, author = {Duerrschmid, Clemens and He, Yanlin and Wang, Chunmei and Li, Chia and Bournat, Juan C and Romere, Chase and Saha, Pradip K and Lee, Mark E and Phillips, Kevin J and Jain, Mahim and Jia, Peilin and Zhao, Zhongming and Farias, Monica and Wu, Qi and Milewicz, Dianna M and Sutton, V Reid and Moore, David D and Butte, Nancy F and Krashes, Michael J and Xu, Yong and Chopra, Atul R} } @article {405, title = {Mutations in sphingosine-1-phosphate lyase cause nephrosis with ichthyosis and adrenal insufficiency.}, journal = {J Clin Invest}, volume = {127}, year = {2017}, month = {2017 Mar 01}, pages = {912-928}, abstract = {

Steroid-resistant nephrotic syndrome (SRNS) causes 15\% of chronic kidney disease cases. A mutation in 1 of over 40 monogenic genes can be detected in approximately 30\% of individuals with SRNS whose symptoms manifest before 25 years of age. However, in many patients, the genetic etiology remains unknown. Here, we have performed whole exome sequencing to identify recessive causes of SRNS. In 7 families with SRNS and facultative ichthyosis, adrenal insufficiency, immunodeficiency, and neurological defects, we identified 9 different recessive mutations in SGPL1, which encodes sphingosine-1-phosphate (S1P) lyase. All mutations resulted in reduced or absent SGPL1 protein and/or enzyme activity. Overexpression of cDNA representing SGPL1 mutations resulted in subcellular mislocalization of SGPL1. Furthermore, expression of WT human SGPL1 rescued growth of SGPL1-deficient dpl1Δ yeast strains, whereas expression of disease-associated variants did not. Immunofluorescence revealed SGPL1 expression in mouse podocytes and mesangial cells. Knockdown of Sgpl1 in rat mesangial cells inhibited cell migration, which was partially rescued by VPC23109, an S1P receptor antagonist. In Drosophila, Sply mutants, which lack SGPL1, displayed a phenotype reminiscent of nephrotic syndrome in nephrocytes. WT Sply, but not the disease-associated variants, rescued this phenotype. Together, these results indicate that SGPL1 mutations cause a syndromic form of SRNS.

}, keywords = {Aldehyde-Lyases, Animals, Cell Line, Cell Movement, Drosophila melanogaster, Drosophila Proteins, Female, Humans, Ichthyosis, Lamellar, Male, Mesangial Cells, Mice, Mice, Knockout, Mutation, Nephrotic Syndrome, Protein Transport, Rats}, issn = {1558-8238}, doi = {10.1172/JCI89626}, author = {Lovric, Svjetlana and Goncalves, Sara and Gee, Heon Yung and Oskouian, Babak and Srinivas, Honnappa and Choi, Won-Il and Shril, Shirlee and Ashraf, Shazia and Tan, Weizhen and Rao, Jia and Airik, Merlin and Schapiro, David and Braun, Daniela A and Sadowski, Carolin E and Widmeier, Eugen and Jobst-Schwan, Tilman and Schmidt, Johanna Magdalena and Girik, Vladimir and Capitani, Guido and Suh, Jung H and Lachauss{\'e}e, No{\"e}lle and Arrondel, Christelle and Patat, Julie and Gribouval, Olivier and Furlano, Monica and Boyer, Olivia and Schmitt, Alain and Vuiblet, Vincent and Hashmi, Seema and Wilcken, Rainer and Bernier, Francois P and Innes, A Micheil and Parboosingh, Jillian S and Lamont, Ryan E and Midgley, Julian P and Wright, Nicola and Majewski, Jacek and Zenker, Martin and Schaefer, Franz and Kuss, Navina and Greil, Johann and Giese, Thomas and Schwarz, Klaus and Catheline, Vilain and Schanze, Denny and Franke, Ingolf and Sznajer, Yves and Truant, Anne S and Adams, Brigitte and D{\'e}sir, Julie and Biemann, Ronald and Pei, York and Ars, Elisabet and Lloberas, Nuria and Madrid, Alvaro and Dharnidharka, Vikas R and Connolly, Anne M and Willing, Marcia C and Cooper, Megan A and Lifton, Richard P and Simons, Matias and Riezman, Howard and Antignac, Corinne and Saba, Julie D and Hildebrandt, Friedhelm} } @article {58, title = {Association of MTOR Mutations With Developmental Brain Disorders, Including Megalencephaly, Focal Cortical Dysplasia, and Pigmentary Mosaicism.}, journal = {JAMA Neurol}, volume = {73}, year = {2016}, month = {2016 07 01}, pages = {836-845}, abstract = {

IMPORTANCE: Focal cortical dysplasia (FCD), hemimegalencephaly, and megalencephaly constitute a spectrum of malformations of cortical development with shared neuropathologic features. These disorders are associated with significant childhood morbidity and mortality.

OBJECTIVE: To identify the underlying molecular cause of FCD, hemimegalencephaly, and diffuse megalencephaly.

DESIGN, SETTING, AND PARTICIPANTS: Patients with FCD, hemimegalencephaly, or megalencephaly (mean age, 11.7 years; range, 2-32 years) were recruited from Pediatric Hospital A. Meyer, the University of Hong Kong, and Seattle Children{\textquoteright}s Research Institute from June 2012 to June 2014. Whole-exome sequencing (WES) was performed on 8 children with FCD or hemimegalencephaly using standard-depth (50-60X) sequencing in peripheral samples (blood, saliva, or skin) from the affected child and their parents and deep (150-180X) sequencing in affected brain tissue. Targeted sequencing and WES were used to screen 93 children with molecularly unexplained diffuse or focal brain overgrowth. Histopathologic and functional assays of phosphatidylinositol 3-kinase-AKT (serine/threonine kinase)-mammalian target of rapamycin (mTOR) pathway activity in resected brain tissue and cultured neurons were performed to validate mutations.

MAIN OUTCOMES AND MEASURES: Whole-exome sequencing and targeted sequencing identified variants associated with this spectrum of developmental brain disorders.

RESULTS: Low-level mosaic mutations of MTOR were identified in brain tissue in 4 children with FCD type 2a with alternative allele fractions ranging from 0.012 to 0.086. Intermediate-level mosaic mutation of MTOR (p.Thr1977Ile) was also identified in 3 unrelated children with diffuse megalencephaly and pigmentary mosaicism in skin. Finally, a constitutional de novo mutation of MTOR (p.Glu1799Lys) was identified in 3 unrelated children with diffuse megalencephaly and intellectual disability. Molecular and functional analysis in 2 children with FCD2a from whom multiple affected brain tissue samples were available revealed a mutation gradient with an epicenter in the most epileptogenic area. When expressed in cultured neurons, all MTOR mutations identified here drive constitutive activation of mTOR complex 1 and enlarged neuronal size.

CONCLUSIONS AND RELEVANCE: In this study, mutations of MTOR were associated with a spectrum of brain overgrowth phenotypes extending from FCD type 2a to diffuse megalencephaly, distinguished by different mutations and levels of mosaicism. These mutations may be sufficient to cause cellular hypertrophy in cultured neurons and may provide a demonstration of the pattern of mosaicism in brain and substantiate the link between mosaic mutations of MTOR and pigmentary mosaicism in skin.

}, keywords = {Adolescent, Adult, Amino Acids, Animals, Cells, Cultured, Cerebral Cortex, Child, Child, Preschool, Developmental Disabilities, Embryo, Mammalian, Female, Gene Expression Regulation, Genetic Association Studies, Humans, Intercellular Signaling Peptides and Proteins, Male, Malformations of Cortical Development, Mechanistic Target of Rapamycin Complex 1, Megalencephaly, Mosaicism, Multiprotein Complexes, Mutation, Nerve Tissue Proteins, Neurons, Rats, Retrospective Studies, TOR Serine-Threonine Kinases, Young Adult}, issn = {2168-6157}, doi = {10.1001/jamaneurol.2016.0363}, author = {Mirzaa, Ghayda M and Campbell, Catarina D and Solovieff, Nadia and Goold, Carleton and Jansen, Laura A and Menon, Suchithra and Timms, Andrew E and Conti, Valerio and Biag, Jonathan D and Adams, Carissa and Boyle, Evan August and Collins, Sarah and Ishak, Gisele and Poliachik, Sandra and Girisha, Katta M and Yeung, Kit San and Chung, Brian Hon Yin and Rahikkala, Elisa and Gunter, Sonya A and McDaniel, Sharon S and Macmurdo, Colleen Forsyth and Bernstein, Jonathan A and Martin, Beth and Leary, Rebecca and Mahan, Scott and Liu, Shanming and Weaver, Molly and Doerschner, Michael and Jhangiani, Shalini and Muzny, Donna M and Boerwinkle, Eric and Gibbs, Richard A and Lupski, James R and Shendure, Jay and Saneto, Russell P and Novotny, Edward J and Wilson, Christopher J and Sellers, William R and Morrissey, Michael and Hevner, Robert F and Ojemann, Jeffrey G and Guerrini, Renzo and Murphy, Leon O and Winckler, Wendy and Dobyns, William B} } @article {85, title = {Recurrent recessive mutation in deoxyguanosine kinase causes idiopathic noncirrhotic portal hypertension.}, journal = {Hepatology}, volume = {63}, year = {2016}, month = {2016 06}, pages = {1977-86}, abstract = {

UNLABELLED: Despite advances in the diagnosis and management of idiopathic noncirrhotic portal hypertension, its pathogenesis remains elusive. Insight may be gained from study of early-onset familial idiopathic noncirrhotic portal hypertension, in which Mendelian mutations may account for disease. We performed exome sequencing of eight subjects from six kindreds with onset of portal hypertension of indeterminate etiology during infancy or childhood. Three subjects from two consanguineous families shared the identical rare homozygous p.N46S mutation in DGUOK, a deoxyguanosine kinase required for mitochondrial DNA replication; haplotype sharing demonstrated that the mutation in the two families was inherited from a remote common ancestor. All three affected subjects had stable portal hypertension with noncirrhotic liver disease for 6-16 years of follow-up. This mutation impairs adenosine triphosphate binding and reduces catalytic activity. Loss-of-function mutations in DGUOK have previously been implicated in cirrhosis and liver failure but not in isolated portal hypertension. Interestingly, treatment of patients with human immunodeficiency viral infection with the nucleoside analogue didanosine is known to cause portal hypertension in a subset of patients and lowers deoxyguanosine kinase levels in vitro; the current findings implicate these effects on deoxyguanosine kinase in the causal mechanism.

CONCLUSION: Our findings provide new insight into the mechanisms mediating inherited and acquired noncirrhotic portal hypertension, expand the phenotypic spectrum of DGUOK deficiency, and provide a new genetic test for a specific cause of idiopathic noncirrhotic portal hypertension. (Hepatology 2016;63:1977-1986).

}, keywords = {Adolescent, Amino Acid Sequence, Animals, Cattle, Child, Child, Preschool, DNA Mutational Analysis, Dogs, Female, Genes, Recessive, Homozygote, Humans, Hypertension, Portal, Infant, Liver Failure, Male, Molecular Sequence Data, Pedigree, Phosphotransferases (Alcohol Group Acceptor), Principal Component Analysis, Rats, Young Adult}, issn = {1527-3350}, doi = {10.1002/hep.28499}, author = {Vilarinho, S{\'\i}lvia and Sari, Sinan and Yilmaz, G{\"u}ldal and Stiegler, Amy L and Boggon, Titus J and Jain, Dhanpat and Akyol, G{\"u}len and Dalgi{\c c}, Buket and G{\"u}nel, Murat and Lifton, Richard P} } @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} }