Scientific Publications

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351 Results

2018

De novo truncating variants in the intronless IRF2BPL are responsible for developmental epileptic encephalopathy

Tran Mau-Them F, Guibaud L, Duplomb L, Keren B, Lindstrom K, Marey I, Mochel F, van den Boogaard MJ, Oegema R, Nava C, Masurel A, Jouan T, Jansen FE, Au M, Chen AH, Cho M, Duffourd Y, Lozier E, Konovalov F, Sharkov A, Korostelev S, Urteaga B, Dickson P, Vera M, Martínez-Agosto JA, Begemann A, Zweier M, Schmitt-Mechelke T, Rauch A, Philippe C, van Gassen K, Nelson S, Graham JM Jr, Friedman J, Faivre L, Lin HJ, Thauvin-Robinet C, Vitobello A.

Genet Med. 2019 Apr;21(4):1008-1014. doi: 10.1038/s41436-018-0143-0. Epub 2018 Aug 31. ABSTRACT PURPOSE: Developmental and epileptic encephalopathies (DEEs) are severe clinical conditions characterized by stagnation or decline of cognitive and behavioral abilities preceded, accompanied or followed by seizures. Because DEEs are clinically and genetically heterogeneous, next-generation sequencing, especially exome sequencing (ES), is becoming a first-tier strategy to identify the molecular etiologies of these disorders. METHODS: We combined ES analysis and international data sharing. RESULTS: We identified 11 unrelated individuals with DEE and de novo heterozygous truncating variants in the interferon regulatory factor 2-binding protein-like gene (IRF2BPL). The 11 individuals allowed for delineation of a consistent neurodevelopmental disorder characterized by mostly normal initial psychomotor development followed by severe global neurological regression and epilepsy with nonspecific electroencephalogram (EEG) abnormalities and variable central nervous system (CNS) anomalies. IRF2BPL, also known as enhanced at puberty protein 1 (EAP1), encodes a transcriptional regulator containing a C-terminal RING-finger domain common to E3 ubiquitin ligases. This domain is required for its repressive and transactivating transcriptional properties. The variants identified are expected to encode a protein lacking the C-terminal RING-finger domain. CONCLUSIONS: These data support the causative role of truncating IRF2BPL variants in pediatric neurodegeneration and expand the spectrum of transcriptional regulators identified as molecular factors implicated in genetic developmental and epileptic encephalopathies. PMID:30166628 | DOI:10.1038/s41436-018-0143-0

September 1, 2018

Genetic variants in components of the NALCN-UNC80-UNC79 ion channel complex cause a broad clinical phenotype (NALCN channelopathies)

Bramswig NC, Bertoli-Avella AM, Albrecht B, Al Aqeel AI, Alhashem A, Al-Sannaa N, Bah M, Bröhl K, Depienne C, Dorison N, Doummar D, Ehmke N, Elbendary HM, Gorokhova S, Héron D, Horn D, James K, Keren B, Kuechler A, Ismail S, Issa MY, Marey I, Mayer M, McEvoy-Venneri J, Megarbane A, Mignot C, Mohamed S, Nava C, Philip N, Ravix C, Rolfs A, Sadek AA, Segebrecht L, Stanley V, Trautman C, Valence S, Villard L, Wieland T, Engels H, Strom TM, Zaki MS, Gleeson JG, Lüdecke HJ, Bauer P, Wieczorek D.

Hum Genet. 2018 Sep;137(9):753-768. doi: 10.1007/s00439-018-1929-5. Epub 2018 Aug 23. ABSTRACT NALCN is a conserved cation channel, which conducts a permanent sodium leak current and regulates resting membrane potential and neuronal excitability. It is part of a large ion channel complex, the “NALCN channelosome”, consisting of multiple proteins including UNC80 and UNC79. The predominant neuronal expression pattern and its function suggest an important role in neuronal function and disease. So far, biallelic NALCN and UNC80 variants have been described in a small number of individuals leading to infantile hypotonia, psychomotor retardation, and characteristic facies 1 (IHPRF1, OMIM 615419) and 2 (IHPRF2, OMIM 616801), respectively. Heterozygous de novo NALCN missense variants in the S5/S6 pore-forming segments lead to congenital contractures of the limbs and face, hypotonia, and developmental delay (CLIFAHDD, OMIM 616266) with some clinical overlap. In this study, we present detailed clinical information of 16 novel individuals with biallelic NALCN variants, 1 individual with a heterozygous de novo NALCN missense variant and an interesting clinical phenotype without contractures, and 12 individuals with biallelic UNC80 variants. We report for the first time a missense NALCN variant located in the predicted S6 pore-forming unit inherited in an autosomal-recessive manner leading to mild IHPRF1. We show evidence of clinical variability, especially among IHPRF1-affected individuals, and discuss differences between the IHPRF1- and IHPRF2 phenotypes. In summary, we provide a comprehensive overview of IHPRF1 and IHPRF2 phenotypes based on the largest cohort of individuals reported so far and provide additional insights into the clinical phenotypes of these neurodevelopmental diseases to help improve counseling of affected families. PMID:30167850 | PMC:PMC6671679 | DOI:10.1007/s00439-018-1929-5

September 1, 2018

Paroxysmal motor disorders: expanding phenotypes lead to coalescing genotypes

Zima L, Ceulemans S, Reiner G, Galosi S, Chen D, Sahagian M, Haas RH, Hyland K, Friedman J.

Ann Clin Transl Neurol. 2018 Jul 17;5(8):996-1010. doi: 10.1002/acn3.597. eCollection 2018 Aug.

ABSTRACT

Paroxysmal movement disorders encompass varied motor phenomena. Less recognized features and wide phenotypic and genotypic heterogeneity are impediments to straightforward molecular diagnosis. We describe a family with episodic ataxia type 1, initially mis-characterized as paroxysmal dystonia to illustrate this diagnostic challenge. We summarize clinical features in affected individuals to highlight underappreciated aspects and provide comprehensive phenotypic description of the rare familial KCNA1 mutation. Delayed diagnosis in this family is emblematic of the broader challenge of diagnosing other paroxysmal motor disorders. We summarize genotypic and phenotypic overlap and provide a suggested diagnostic algorithm for approaching patients with these conditions.

PMID:30128325 | PMC:PMC6093839 | DOI:10.1002/acn3.597

August 22, 2018

Genetic Neurologic DiseaseNeurogenomics

Genomic sequencing in acutely ill infants: what will it take to demonstrate clinical value?

Grosse SD, Farnaes L.

Genet Med. 2019 Feb;21(2):269-271. doi: 10.1038/s41436-018-0124-3. Epub 2018 Aug 13. NO ABSTRACT PMID:30100610 | PMC:PMC6691721 | DOI:10.1038/s41436-018-0124-3

August 14, 2018

Biallelic Mutations in ADPRHL2, Encoding ADP-Ribosylhydrolase 3, Lead to a Degenerative Pediatric Stress-Induced Epileptic Ataxia Syndrome

Ghosh SG, Becker K, Huang H, Dixon-Salazar T, Chai G, Salpietro V, Al-Gazali L, Waisfisz Q, Wang H, Vaux KK, Stanley V, Manole A, Akpulat U, Weiss MM, Efthymiou S, Hanna MG, Minetti C, Striano P, Pisciotta L, De Grandis E, Altmüller J, Nürnberg P, Thiele H, Yis U, Okur TD, Polat AI, Amiri N, Doosti M, Karimani EG, Toosi MB, Haddad G, Karakaya M, Wirth B, van Hagen JM, Wolf NI, Maroofian R, Houlden H, Cirak S, Gleeson JG.

Am J Hum Genet. 2018 Sep 6;103(3):431-439. doi: 10.1016/j.ajhg.2018.07.010. Epub 2018 Aug 9. ABSTRACT ADP-ribosylation, the addition of poly-ADP ribose (PAR) onto proteins, is a response signal to cellular challenges, such as excitotoxicity or oxidative stress. This process is catalyzed by a group of enzymes referred to as poly(ADP-ribose) polymerases (PARPs). Because the accumulation of proteins with this modification results in cell death, its negative regulation restores cellular homeostasis: a process mediated by poly-ADP ribose glycohydrolases (PARGs) and ADP-ribosylhydrolase proteins (ARHs). Using linkage analysis and exome or genome sequencing, we identified recessive inactivating mutations in ADPRHL2 in six families. Affected individuals exhibited a pediatric-onset neurodegenerative disorder with progressive brain atrophy, developmental regression, and seizures in association with periods of stress, such as infections. Loss of the Drosophila paralog Parg showed lethality in response to oxidative challenge that was rescued by human ADPRHL2, suggesting functional conservation. Pharmacological inhibition of PARP also rescued the phenotype, suggesting the possibility of postnatal treatment for this genetic condition. PMID:30100084 | PMC:PMC6128219 | DOI:10.1016/j.ajhg.2018.07.010

August 14, 2018

Urea Cycle Dysregulation Generates Clinically Relevant Genomic and Biochemical Signatures

Lee JS, Adler L, Karathia H, Carmel N, Rabinovich S, Auslander N, Keshet R, Stettner N, Silberman A, Agemy L, Helbling D, Eilam R, Sun Q, Brandis A, Malitsky S, Itkin M, Weiss H, Pinto S, Kalaora S, Levy R, Barnea E, Admon A, Dimmock D, Stern-Ginossar N, Scherz A, Nagamani SCS, Unda M, Wilson DM 3rd, Elhasid R, Carracedo A, Samuels Y, Hannenhalli S, Ruppin E, Erez A.

Cell. 2018 Sep 6;174(6):1559-1570.e22. doi: 10.1016/j.cell.2018.07.019. Epub 2018 Aug 9. ABSTRACT The urea cycle (UC) is the main pathway by which mammals dispose of waste nitrogen. We find that specific alterations in the expression of most UC enzymes occur in many tumors, leading to a general metabolic hallmark termed “UC dysregulation” (UCD). UCD elicits nitrogen diversion toward carbamoyl-phosphate synthetase2, aspartate transcarbamylase, and dihydrooratase (CAD) activation and enhances pyrimidine synthesis, resulting in detectable changes in nitrogen metabolites in both patient tumors and their bio-fluids. The accompanying excess of pyrimidine versus purine nucleotides results in a genomic signature consisting of transversion mutations at the DNA, RNA, and protein levels. This mutational bias is associated with increased numbers of hydrophobic tumor antigens and a better response to immune checkpoint inhibitors independent of mutational load. Taken together, our findings demonstrate that UCD is a common feature of tumors that profoundly affects carcinogenesis, mutagenesis, and immunotherapy response. PMID:30100185 | PMC:PMC6225773 | DOI:10.1016/j.cell.2018.07.019

August 14, 2018

Mutations in LNPK, Encoding the Endoplasmic Reticulum Junction Stabilizer Lunapark, Cause a Recessive Neurodevelopmental Syndrome

Breuss MW, Nguyen A, Song Q, Nguyen T, Stanley V, James KN, Musaev D, Chai G, Wirth SA, Anzenberg P, George RD, Johansen A, Ali S, Zia-Ur-Rehman M, Sultan T, Zaki MS,Gleeson JG.

Am J Hum Genet. 2018 Aug 2;103(2):296-304. doi: 10.1016/j.ajhg.2018.06.011. Epub 2018 Jul 19. ABSTRACT The dynamic shape of the endoplasmic reticulum (ER) is a reflection of its wide variety of critical cell biological functions. Consequently, perturbation of ER-shaping proteins can cause a range of human phenotypes. Here, we describe three affected children (from two consanguineous families) who carry homozygous loss-of-function mutations in LNPK (previously known as KIAA1715); this gene encodes lunapark, which is proposed to serve as a curvature-stabilizing protein within tubular three-way junctions of the ER. All individuals presented with severe psychomotor delay, intellectual disability, hypotonia, epilepsy, and corpus callosum hypoplasia, and two of three showed mild cerebellar hypoplasia and atrophy. Consistent with a proposed role in neurodevelopmental disease, LNPK was expressed during brain development in humans and mice and was present in neurite-like processes in differentiating human neural progenitor cells. Affected cells showed the absence of full-length lunapark, aberrant ER structures, and increased luminal mass density. Together, our results implicate the ER junction stabilizer lunapark in establishing the corpus callosum. PMID:30032983 | PMC:PMC6080764 | DOI:10.1016/j.ajhg.2018.06.011

July 24, 2018

Biallelic loss of human CTNNA2, encoding αN-catenin, leads to ARP2/3 complex overactivity and disordered cortical neuronal migration

Schaffer AE, Breuss MW, Caglayan AO, Al-Sanaa N, Al-Abdulwahed HY, Kaymakçalan H, Yılmaz C, Zaki MS, Rosti RO, Copeland B, Baek ST, Musaev D, Scott EC, Ben-Omran T, Kariminejad A, Kayserili H, Mojahedi F, Kara M, Cai N, Silhavy JL, Elsharif S, Fenercioglu E, Barshop BA, Kara B, Wang R, Stanley V, James KN, Nachnani R, Kalur A, Megahed H, Incecik F, Danda S, Alanay Y, Faqeih E, Melikishvili G, Mansour L, Miller I, Sukhudyan B, Chelly J, Dobyns WB, Bilguvar K, Jamra RA, Gunel M, Gleeson JG.

Nat Genet. 2018 Aug;50(8):1093-1101. doi: 10.1038/s41588-018-0166-0. Epub 2018 Jul 16. ABSTRACT Neuronal migration defects, including pachygyria, are among the most severe developmental brain defects in humans. Here, we identify biallelic truncating mutations in CTNNA2, encoding αN-catenin, in patients with a distinct recessive form of pachygyria. CTNNA2 was expressed in human cerebral cortex, and its loss in neurons led to defects in neurite stability and migration. The αN-catenin paralog, αE-catenin, acts as a switch regulating the balance between β-catenin and Arp2/3 actin filament activities¹. Loss of αN-catenin did not affect β-catenin signaling, but recombinant αN-catenin interacted with purified actin and repressed ARP2/3 actin-branching activity. The actin-binding domain of αN-catenin or ARP2/3 inhibitors rescued the neuronal phenotype associated with CTNNA2 loss, suggesting ARP2/3 de-repression as a potential disease mechanism. Our findings identify CTNNA2 as the first catenin family member with biallelic mutations in humans, causing a new pachygyria syndrome linked to actin regulation, and uncover a key factor involved in ARP2/3 repression in neurons. PMID:30013181 | PMC:PMC6072555 | DOI:10.1038/s41588-018-0166-0

July 18, 2018

Meta-analysis of the diagnostic and clinical utility of genome and exome sequencing and chromosomal microarray in children with suspected genetic diseases

NPJ Genom Med. 2018 Jul 9;3:16. doi: 10.1038/s41525-018-0053-8. eCollection 2018.

ABSTRACT

Genetic diseases are leading causes of childhood mortality. Whole-genome sequencing (WGS) and whole-exome sequencing (WES) are relatively new methods for diagnosing genetic diseases, whereas chromosomal microarray (CMA) is well established. Here we compared the diagnostic utility (rate of causative, pathogenic, or likely pathogenic genotypes in known disease genes) and clinical utility (proportion in whom medical or surgical management was changed by diagnosis) of WGS, WES, and CMA in children with suspected genetic diseases by systematic review of the literature (January 2011-August 2017) and meta-analysis, following MOOSE/PRISMA guidelines. In 37 studies, comprising 20,068 children, diagnostic utility of WGS (0.41, 95% CI 0.34-0.48, I² = 44%) and WES (0.36, 95% CI 0.33-0.40, I² = 83%) were qualitatively greater than CMA (0.10, 95% CI 0.08-0.12, I² = 81%). Among studies published in 2017, the diagnostic utility of WGS was significantly greater than CMA (P < 0.0001, I² = 13% and I² = 40%, respectively). Among studies featuring within-cohort comparisons, the diagnostic utility of WES was significantly greater than CMA (P < 0.001, I² = 36%). The diagnostic utility of WGS and WES were not significantly different. In studies featuring within-cohort comparisons of WGS/WES, the likelihood of diagnosis was significantly greater for trios than singletons (odds ratio 2.04, 95% CI 1.62-2.56, I² = 12%; P < 0.0001). Diagnostic utility of WGS/WES with hospital-based interpretation (0.42, 95% CI 0.38-0.45, I² = 48%) was qualitatively higher than that of reference laboratories (0.29, 95% CI 0.27-0.31, I² = 49%); this difference was significant among studies published in 2017 (P < .0001, I² = 22% and I² = 26%, respectively). The clinical utility of WGS (0.27, 95% CI 0.17-0.40, I² = 54%) and WES (0.17, 95% CI 0.12-0.24, I² = 76%) were higher than CMA (0.06, 95% CI 0.05-0.07, I² = 42%); this difference was significant for WGS vs CMA (P < 0.0001). In conclusion, in children with suspected genetic diseases, the diagnostic and clinical utility of WGS/WES were greater than CMA. Subgroups with higher WGS/WES diagnostic utility were trios and those receiving hospital-based interpretation. WGS/WES should be considered a first-line genomic test for children with suspected genetic diseases.

PMID:30002876 | PMC:PMC6037748 | DOI:10.1038/s41525-018-0053-8

July 14, 2018

Whole exome sequencing reveals HSPA1L as a genetic risk factor for spontaneous preterm birth

Huusko JM, Karjalainen MK, Graham BE, Zhang G, Farrow EG, Miller NA, Jacobsson B, Eidem HR, Murray JC, Bedell B, Breheny P, Brown NW, Bødker FL, Litterman NK, Jiang PP, Russell L, Hinds DA, Hu Y; 23andMe Research Team, Rokas A, Teramo K, Christensen K, Williams SM, Rämet M, Kingsmore SF, Ryckman KK, Hallman M, Muglia LJ.

PLoS Genet. 2018 Jul 12;14(7):e1007394. doi: 10.1371/journal.pgen.1007394. eCollection 2018 Jul. ABSTRACT Preterm birth is a leading cause of morbidity and mortality in infants. Genetic and environmental factors play a role in the susceptibility to preterm birth, but despite many investigations, the genetic basis for preterm birth remain largely unknown. Our objective was to identify rare, possibly damaging, nucleotide variants in mothers from families with recurrent spontaneous preterm births (SPTB). DNA samples from 17 Finnish mothers who delivered at least one infant preterm were subjected to whole exome sequencing. All mothers were of northern Finnish origin and were from seven multiplex families. Additional replication samples of European origin consisted of 93 Danish sister pairs (and two sister triads), all with a history of a preterm delivery. Rare exonic variants (frequency <1%) were analyzed to identify genes and pathways likely to affect SPTB susceptibility. We identified rare, possibly damaging, variants in genes that were common to multiple affected individuals. The glucocorticoid receptor signaling pathway was the most significant (p<1.7e-8) with genes containing these variants in a subgroup of ten Finnish mothers, each having had 2-4 SPTBs. This pathway was replicated among the Danish sister pairs. A gene in this pathway, heat shock protein family A (Hsp70) member 1 like (HSPA1L), contains two likely damaging missense alleles that were found in four different Finnish families. One of the variants (rs34620296) had a higher frequency in cases compared to controls (0.0025 vs. 0.0010, p = 0.002) in a large preterm birth genome-wide association study (GWAS) consisting of mothers of general European ancestry. Sister pairs in replication samples also shared rare, likely damaging HSPA1L variants. Furthermore, in silico analysis predicted an additional phosphorylation site generated by rs34620296 that could potentially affect chaperone activity or HSPA1L protein stability. Finally, in vitro functional experiment showed a link between HSPA1L activity and decidualization. In conclusion, rare, likely damaging, variants in HSPA1L were observed in multiple families with recurrent SPTB. PMID:30001343 | PMC:PMC6042692 | DOI:10.1371/journal.pgen.1007394

July 13, 2018

Infant Mortality

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