Scientific Publications

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18 Results

2021

Functional and structural analyses of novel Smith-Kingsmore Syndrome-Associated MTOR variants reveal potential new mechanisms and predictors of pathogenicity

Besterman AD, Althoff T, Elfferich P, Gutierrez-Mejia I, Sadik J, Bernstein JA, van Ierland Y, Kattentidt-Mouravieva AA, Nellist M, Abramson J, Martinez-Agosto JA.

PLoS Genet. 2021 Jul 1;17(7):e1009651. doi: 10.1371/journal.pgen.1009651. Online ahead of print. ABSTRACT Smith-Kingsmore syndrome (SKS) is a rare neurodevelopmental disorder characterized by macrocephaly/megalencephaly, developmental delay, intellectual disability, hypotonia, and seizures. It is caused by dominant missense mutations in MTOR. The pathogenicity of novel variants in MTOR in patients with neurodevelopmental disorders can be difficult to determine and the mechanism by which variants cause disease remains poorly understood. We report 7 patients with SKS with 4 novel MTOR variants and describe their phenotypes. We perform in vitro functional analyses to confirm MTOR activation and interrogate disease mechanisms. We complete structural analyses to understand the 3D properties of pathogenic variants. We examine the accuracy of relative accessible surface area, a quantitative measure of amino acid side-chain accessibility, as a predictor of MTOR variant pathogenicity. We describe novel clinical features of patients with SKS. We confirm MTOR Complex 1 activation and identify MTOR Complex 2 activation as a new potential mechanism of disease in SKS. We find that pathogenic MTOR variants disproportionately cluster in hotspots in the core of the protein, where they disrupt alpha helix packing due to the insertion of bulky amino acid side chains. We find that relative accessible surface area is significantly lower for SKS-associated variants compared to benign variants. We expand the phenotype of SKS and demonstrate that additional pathways of activation may contribute to disease. Incorporating 3D properties of MTOR variants may help in pathogenicity classification. We hope these findings may contribute to improving the precision of care and therapeutic development for individuals with SKS. PMID:34197453 | DOI:10.1371/journal.pgen.1009651

July 9, 2021

Gene Discovery

Rare deleterious mutations of HNRNP genes result in shared neurodevelopmental disorders

Gillentine MA, Wang T, Hoekzema K, Rosenfeld J, Liu P, Guo H, Kim CN, De Vries BBA, Vissers LELM, Nordenskjold M, Kvarnung M, Lindstrand A, Nordgren A, Gecz J, Iascone M, Cereda A, Scatigno A, Maitz S, Zanni G, Bertini E, Zweier C, Schuhmann S, Wiesener A, Pepper M, Panjwani H, Torti E, Abid F, Anselm I, Srivastava S, Atwal P, Bacino CA, Bhat G, Cobian K, Bird LM, Friedman J, Wright MS, Callewaert B, Petit F, Mathieu S, Afenjar A, Christensen CK, White KM, Elpeleg O, Berger I, Espineli EJ, Fagerberg C, Brasch-Andersen C, Hansen LK, Feyma T, Hughes S, Thiffault I, Sullivan B, Yan S, Keller K, Keren B, Mignot C, Kooy F, Meuwissen M, Basinger A, Kukolich M, Philips M, Ortega L, Drummond-Borg M, Lauridsen M, Sorensen K, Lehman A; CAUSES Study, Lopez-Rangel E, Levy P, Lessel D, Lotze T, Madan-Khetarpal S, Sebastian J, Vento J, Vats D, Benman LM, Mckee S, Mirzaa GM, Muss C, Pappas J, Peeters H, Romano C, Elia M, Galesi O, Simon MEH, van Gassen KLI, Simpson K, Stratton R, Syed S, Thevenon J, Palafoll IV, Vitobello A, Bournez M, Faivre L, Xia K; SPARK Consortium, Earl RK, Nowakowski T, Bernier RA, Eichler EE.

Madelyn A Gillentine Genome Med. 2021 Apr 19;13(1):63. doi: 10.1186/s13073-021-00870-6. ABSTRACT BACKGROUND: With the increasing number of genomic sequencing studies, hundreds of genes have been implicated in neurodevelopmental disorders (NDDs). The rate of gene discovery far outpaces our understanding of genotype-phenotype correlations, with clinical characterization remaining a bottleneck for understanding NDDs. Most disease-associated Mendelian genes are members of gene families, and we hypothesize that those with related molecular function share clinical presentations. METHODS: We tested our hypothesis by considering gene families that have multiple members with an enrichment of de novo variants among NDDs, as determined by previous meta-analyses. One of these gene families is the heterogeneous nuclear ribonucleoproteins (hnRNPs), which has 33 members, five of which have been recently identified as NDD genes (HNRNPK, HNRNPU, HNRNPH1, HNRNPH2, and HNRNPR) and two of which have significant enrichment in our previous meta-analysis of probands with NDDs (HNRNPU and SYNCRIP). Utilizing protein homology, mutation analyses, gene expression analyses, and phenotypic characterization, we provide evidence for variation in 12 HNRNP genes as candidates for NDDs. Seven are potentially novel while the remaining genes in the family likely do not significantly contribute to NDD risk. RESULTS: We report 119 new NDD cases (64 de novo variants) through sequencing and international collaborations and combined with published clinical case reports. We consider 235 cases with gene-disruptive single-nucleotide variants or indels and 15 cases with small copy number variants. Three hnRNP-encoding genes reach nominal or exome-wide significance for de novo variant enrichment, while nine are candidates for pathogenic mutations. Comparison of HNRNP gene expression shows a pattern consistent with a role in cerebral cortical development with enriched expression among radial glial progenitors. Clinical assessment of probands (n = 188-221) expands the phenotypes associated with HNRNP rare variants, and phenotypes associated with variation in the HNRNP genes distinguishes them as a subgroup of NDDs. CONCLUSIONS: Overall, our novel approach of exploiting gene families in NDDs identifies new HNRNP-related disorders, expands the phenotypes of known HNRNP-related disorders, strongly implicates disruption of the hnRNPs as a whole in NDDs, and supports that NDD subtypes likely have shared molecular pathogenesis. To date, this is the first study to identify novel genetic disorders based on the presence of disorders in related genes. We also perform the first phenotypic analyses focusing on related genes. Finally, we show that radial glial expression of these genes is likely critical during neurodevelopment. This is important for diagnostics, as well as developing strategies to best study these genes for the development of therapeutics. PMID:33874999 DOI:10.1186/s13073-021-00870-6

April 20, 2021

Gene DiscoveryGenetic Neurologic DiseaseNeurogenomics

2020

Diagnosis of cytomegalovirus infection from clinical whole genome sequencing

Ramchandar N, Ding Y, Farnaes L, Dimmock D, Hobbs C, Kingsmore SF, Bainbridge M.

Sci Rep. 2020 Jul 3;10(1):11020. doi: 10.1038/s41598-020-67656-5. ABSTRACT Rapid whole genome sequencing (rWGS) of peripheral blood has been used to detect microbial DNA in acute infections. Cytomegalovirus (CMV) is a herpesvirus capable of causing severe disease in neonates and immunocompromised patients. We identified CMV in patients undergoing diagnostic rWGS by matching reads that did not align to the human reference genome to a database of microbial genomes. rWGS was conducted on peripheral blood obtained from ill pediatric patients (age 1 day to 18 years). Reads not aligning to the human genome were analyzed using an in-house pipeline to identify DNA consistent with CMV infection. Of 669 patients who received rWGS from July 2016 through July 2019, we identified 28 patients (4.2%) with reads that aligned to the CMV reference genome. Six of these patients had clinical findings consistent with symptomatic CMV infection. Positive results were highly correlated (R² > 0.99, p < 0.001) to a CMV-qPCR assay conducted on DNA isolated from whole blood samples. In acutely ill children receiving rWGS for diagnosis of genetic disease, we propose analysis of patient genetic data to identify CMV, which could impact treatment of up to 4% of children in the intensive care unit. PMID:32620939 | PMC:PMC7335102 | DOI:10.1038/s41598-020-67656-5

July 5, 2020

Gene DiscoveryrWGS

2018

Elucidating the molecular pathogenesis of glioma: integrated germline and somatic profiling of a familial glioma case series.

Jacobs DI, Fukumura K, Bainbridge MN, Armstrong GN, Tsavachidis S, Gu X, Doddapaneni HV, Hu J, Jayaseelan JC, Muzny DM, Huse JT, Bondy ML.

Neuro Oncol. 2018 Nov 12;20(12):1625-1633. doi: 10.1093/neuonc/noy119. PMID: 30165405; PMCID: PMC6231201. Abstract Key points: 1. Familial and sporadic gliomas display highly comparable molecular landscapes. 2. Germline and somatic molecular events target common core pathways involved in gliomagenesis. 3. Carriage of germline glioma risk variants is not associated with somatic events in the same gene. PMID: 30165405 | PMCID: PMC6231201 | DOI: 10.1093/neuonc/noy119

November 12, 2018

Gene Discovery

Comprehensive Profiling of DNA Repair Defects in Breast Cancer Identifies a Novel Class of Endocrine Therapy Resistance Drivers

Anurag M, Punturi N, Hoog J, Bainbridge MN, Ellis MJ, Haricharan S.

Clin Cancer Res. 2018 Oct 1;24(19):4887-4899. doi: 10.1158/1078-0432.CCR-17-3702. Epub 2018 May 23. ABSTRACT Purpose: This study was undertaken to conduct a comprehensive investigation of the role of DNA damage repair (DDR) defects in poor outcome ER⁺ disease. Experimental Design: Expression and mutational status of DDR genes in ER⁺ breast tumors were correlated with proliferative response in neoadjuvant aromatase inhibitor therapy trials (discovery dataset), with outcomes in METABRIC, TCGA, and Loi datasets (validation datasets), and in patient-derived xenografts. A causal relationship between candidate DDR genes and endocrine treatment response, and the underlying mechanism, was then tested in ER⁺ breast cancer cell lines. Results: Correlations between loss of expression of three genes: CETN2 (P < 0.001) and ERCC1 (P = 0.01) from the nucleotide excision repair (NER) and NEIL2 (P = 0.04) from the base excision repair (BER) pathways were associated with endocrine treatment resistance in discovery dataset, and subsequently validated in independent patient cohorts. Complementary mutation analysis supported associations between mutations in NER and BER genes and reduced endocrine treatment response. A causal role for CETN2, NEIL2, and ERCC1 loss in intrinsic endocrine resistance was experimentally validated in ER⁺ breast cancer cell lines, and in ER⁺ patient-derived xenograft models. Loss of CETN2, NEIL2, or ERCC1 induced endocrine treatment resistance by dysregulating G₁-S transition, and therefore, increased sensitivity to CDK4/6 inhibitors. A combined DDR signature score was developed that predicted poor outcome in multiple patient cohorts. Conclusions: This report identifies DDR defects as a new class of endocrine treatment resistance drivers and indicates new avenues for predicting efficacy of CDK4/6 inhibition in the adjuvant treatment setting. Clin Cancer Res; 24(19); 4887-99. ©2018 AACR. PMID:29793947 | PMC:PMC6822623 | DOI:10.1158/1078-0432.CCR-17-3702

May 26, 2018

Gene Discovery

Syndromic congenital myelofibrosis associated with a loss-of-function variant in RBSN

Magoulas PL, Shchelochkov OA, Bainbridge MN, Ben-Shachar S, Yatsenko S, Potocki L, Lewis RA, Searby C, Marcogliese AN, Elghetany MT, Zapata G, Hernández PP, Gadkari M, Einhaus D, Muzny DM, Gibbs RA, Bertuch AA, Scott DA, Corvera S, Franco LM.

Blood. 2018 Aug 9;132(6):658-662. doi: 10.1182/blood-2017-12-824433. Epub 2018 May 21. ABSTRACT Publisher’s Note: There is a Blood Commentary on this article in this issue. PMID:29784638 | PMC:PMC6085991 | DOI:10.1182/blood-2017-12-824433

May 23, 2018

Gene Discovery

2017

Molecular subtyping of tumors from patients with familial glioma

Ruiz VY, Praska CE, Armstrong G, Kollmeyer TM, Yamada S, Decker PA, Kosel ML, Eckel-Passow JE, Lachance DH, Bainbridge MN, Melin BS, Bondy ML, Jenkins RB; Gliogene Consortium.

Neuro Oncol. 2018 May 18;20(6):810-817. doi: 10.1093/neuonc/nox192. ABSTRACT BACKGROUND: Single-gene mutation syndromes account for some familial glioma (FG); however, they make up only a small fraction of glioma families. Gliomas can be classified into 3 major molecular subtypes based on isocitrate dehydrogenase (IDH) mutation and 1p/19q codeletion. We hypothesized that the prevalence of molecular subtypes might differ in familial versus sporadic gliomas and that tumors in the same family should have the same molecular subtype. METHODS: Participants in the FG study (Gliogene) provided samples for germline DNA analysis. Formalin-fixed, paraffin-embedded tumors were obtained from a subset of FG cases, and DNA was extracted. We analyzed tissue from 75 families, including 10 families containing a second affected family member. Copy number variation data were obtained using a first-generation Affymetrix molecular inversion probe (MIP) array. RESULTS: Samples from 62 of 75 (83%) FG cases could be classified into the 3 subtypes. The prevalence of the molecular subtypes was: 30 (48%) IDH-wildtype, 21 (34%) IDH-mutant non-codeleted, and 11 (19%) IDH-mutant and 1p/19q codeleted. This distribution of molecular subtypes was not statistically different from that of sporadic gliomas (P = 0.54). Of 10 paired FG samples, molecular subtypes were concordant for 7 (κ = 0.59): 3 IDH-mutant non-codeleted, 2 IDH-wildtype, and 2 IDH-mutant and 1p/19q codeleted gliomas. CONCLUSIONS: Our data suggest that within individual families, patients develop gliomas of the same molecular subtype. However, we did not observe differences in the prevalence of the molecular subtypes in FG compared with sporadic gliomas. These observations provide further insight into the distribution of molecular subtypes in FG. PMID:29040662 | PMC:PMC5961123 | DOI:10.1093/neuonc/nox192

October 18, 2017

Gene Discovery

Analyses of SLC13A5-epilepsy patients reveal perturbations of TCA cycle.

Bainbridge MN, Cooney E, Miller M, Kennedy AD, Wulff JE, Donti T, Jhangiani SN, Gibbs RA, Elsea SH, Porter BE, Graham BH.

Mol Genet Metab. 2017 Aug;121(4):314-319. doi: 10.1016/j.ymgme.2017.06.009. Epub 2017 Jun 24. PMID: 28673551; PMCID: PMC7539367. Abstract Objective: To interrogate the metabolic profile of five subjects from three families with rare, nonsense and missense mutations in SLC13A5 and Early Infantile Epileptic Encephalopathies (EIEE) characterized by severe, neonatal onset seizures, psychomotor retardation and global developmental delay. Methods: Mass spectrometry of plasma, CSF and urine was used to identify consistently dysregulated analytes in our subjects. Results: Distinctive elevations of citrate and dysregulation of citric acid cycle intermediates, supporting the hypothesis that loss of SLC13A5 function alters tricarboxylic acid cycle (TCA) metabolism and may disrupt metabolic compartmentation in the brain. Significance: Our results indicate that analysis of plasma citrate and other TCA analytes in SLC13A5 deficient patients define a diagnostic metabolic signature that can aid in diagnosing children with this disease. PMID: 28673551 | PMCID: PMC7539367 | DOI: 10.1016/j.ymgme.2017.06.009

June 24, 2017

Gene Discovery

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