MED12 is recurrently mutated in Middle Eastern colorectal cancer.

Gut. 2018 Apr;67(4):663-671

Authors: Siraj AK, Masoodi T, Bu R, Pratheeshkumar P, Al-Sanea N, Ashari LH, Abduljabbar A, Alhomoud S, Al-Dayel F, Alkuraya FS, Al-Kuraya KS

Abstract
OBJECTIVE: Colorectal cancer (CRC) is a common cancer and a leading cause of cancer deaths. Previous studies have identified a number of key steps in the evolution of CRC but our knowledge of driver mutations in CRC remains incomplete. Recognising the potential of studying different human populations to reveal novel insights in disease pathogenesis, we conducted genomic analysis of CRC in Saudi patients.
DESIGN: In the discovery phase of the study, we conducted whole genome sequencing of tumour and corresponding germline DNA in 27 patients with CRC. In addition to known driver mutations, we identified three MED12 somatic mutations. In the replication phase, we employed a next-generation sequencing approach to capture and sequence MED12 and other candidate genes in a larger sample of 400 patients with CRC and confirmed the enrichment for recurrent MED12 mutations.
RESULTS: In order to gain insight into a plausible biological mechanism for the potential role of MED12 mutations in CRC, we studied CRC cell lines that differ substantially in the expression level of MED12, and found the latter to be correlated inversely with transforming growth factor (TGF)-β signalling and directly with apoptosis in response to chemotherapeutic agents. Importantly, these correlations were replicated when MED12 expression was experimentally manipulated.
CONCLUSIONS: Our data expand the recently described role of MED12 as a tumour suppressor in other cancers to include CRC, and suggest TGF-β signalling as a potential mediator of this effect.

PMID: 28183795 [PubMed - indexed for MEDLINE]

Variations in Multiple Syndromic Deafness Genes Mimic Non-syndromic Hearing Loss.

Sci Rep. 2016 08 26;6:31622

Authors: Bademci G, Cengiz FB, Foster Ii J, Duman D, Sennaroglu L, Diaz-Horta O, Atik T, Kirazli T, Olgun L, Alper H, Menendez I, Loclar I, Sennaroglu G, Tokgoz-Yilmaz S, Guo S, Olgun Y, Mahdieh N, Bonyadi M, Bozan N, Ayral A, Ozkinay F, Yildirim-Baylan M, Blanton SH, Tekin M

Abstract
The genetics of both syndromic (SHL) and non-syndromic hearing loss (NSHL) is characterized by a high degree of genetic heterogeneity. We analyzed whole exome sequencing data of 102 unrelated probands with apparently NSHL without a causative variant in known NSHL genes. We detected five causative variants in different SHL genes (SOX10, MITF, PTPN11, CHD7, and KMT2D) in five (4.9%) probands. Clinical re-evaluation of these probands shows that some of them have subtle syndromic findings, while none of them meets clinical criteria for the diagnosis of the associated syndrome (Waardenburg (SOX10 and MITF), Kallmann (CHD7 and SOX10), Noonan/LEOPARD (PTPN11), CHARGE (CHD7), or Kabuki (KMT2D). This study demonstrates that individuals who are evaluated for NSHL can have pathogenic variants in SHL genes that are not usually considered for etiologic studies.

PMID: 27562378 [PubMed - indexed for MEDLINE]

Expanding the phenotypic spectrum associated with OPHN1 variants.

Eur J Med Genet. 2018 Jun 27;:

Authors: Schwartz TS, Wojcik MH, Pelletier RC, Edward HL, Picker JD, Holm IA, Towne MC, Beggs AH, Agrawal PB

Abstract
Genomic sequencing has allowed for the characterization of new gene-to-disease relationships, as well as the identification of variants in established disease genes in patients who do not fit the classically-described phenotype. This is especially true in rare syndromes where the clinical spectrum is not fully known. After a lengthy and costly diagnostic odyssey, patients with atypical presentations may be left with many questions even after a genetic diagnosis is identified. We present a 22-year old male with hypotonia, developmental delay, seizure disorder, and dysmorphic facial features who enrolled in our rare disease research center at 18 years of age, where exome sequencing revealed a novel, likely pathogenic variant in the OPHN1 gene. Through efforts by the study team and collaborations with the larger genetics community, contacts with other families with OPHN1 variants were eventually made, and outreach by these families expanded the patient network. This partnership between families and researchers facilitated the gathering of phenotypic information, allowing for comparison of clinical presentations among three new patients and those previously reported in the literature. These comparisons found previously unreported commonalities between the newly identified patients, such as the presence of otitis media and the lack of genitourinary abnormalities (i.e. hypoplastic scrotum, microphallus, cryptorchidism), which had been noted to be classic features of patients with OPHN1 variants. As genomic sequencing becomes more common, connecting patients with novel variants in the same gene will facilitate phenotypic analysis and continue to refine the clinical spectrum associated with that gene.

PMID: 29960046 [PubMed - as supplied by publisher]

Biallelic SQSTM1 mutations in early-onset, variably progressive neurodegeneration.

Neurology. 2018 Jun 29;:

Authors: Muto V, Flex E, Kupchinsky Z, Primiano G, Galehdari H, Dehghani M, Cecchetti S, Carpentieri G, Rizza T, Mazaheri N, Sedaghat A, Vahidi Mehrjardi MY, Traversa A, Di Nottia M, Kousi MM, Jamshidi Y, Ciolfi A, Caputo V, Malamiri RA, Pantaleoni F, Martinelli S, Jeffries AR, Zeighami J, Sherafat A, Di Giuda D, Shariati GR, Carrozzo R, Katsanis N, Maroofian R, Servidei S, Tartaglia M

Abstract
OBJECTIVE: To characterize clinically and molecularly an early-onset, variably progressive neurodegenerative disorder characterized by a cerebellar syndrome with severe ataxia, gaze palsy, dyskinesia, dystonia, and cognitive decline affecting 11 individuals from 3 consanguineous families.
METHODS: We used whole-exome sequencing (WES) (families 1 and 2) and a combined approach based on homozygosity mapping and WES (family 3). We performed in vitro studies to explore the effect of the nontruncating SQSTM1 mutation on protein function and the effect of impaired SQSTM1 function on autophagy. We analyzed the consequences of sqstm1 down-modulation on the structural integrity of the cerebellum in vivo using zebrafish as a model.
RESULTS: We identified 3 homozygous inactivating variants, including a splice site substitution (c.301+2T>A) causing aberrant transcript processing and accelerated degradation of a resulting protein lacking exon 2, as well as 2 truncating changes (c.875_876insT and c.934_936delinsTGA). We show that loss of SQSTM1 causes impaired production of ubiquitin-positive protein aggregates in response to misfolded protein stress and decelerated autophagic flux. The consequences of sqstm1 down-modulation on the structural integrity of the cerebellum in zebrafish documented a variable but reproducible phenotype characterized by cerebellum anomalies ranging from depletion of axonal connections to complete atrophy. We provide a detailed clinical characterization of the disorder; the natural history is reported for 2 siblings who have been followed up for >20 years.
CONCLUSIONS: This study offers an accurate clinical characterization of this recently recognized neurodegenerative disorder caused by biallelic inactivating mutations in SQSTM1 and links this phenotype to defective selective autophagy.

PMID: 29959261 [PubMed - as supplied by publisher]

GAPVD1 and ANKFY1 Mutations Implicate RAB5 Regulation in Nephrotic Syndrome.

J Am Soc Nephrol. 2018 Jun 29;:

Authors: Hermle T, Schneider R, Schapiro D, Braun DA, van der Ven AT, Warejko JK, Daga A, Widmeier E, Nakayama M, Jobst-Schwan T, Majmundar AJ, Ashraf S, Rao J, Finn LS, Tasic V, Hernandez JD, Bagga A, Jalalah SM, El Desoky S, Kari JA, Laricchia KM, Lek M, Rehm HL, MacArthur DG, Mane S, Lifton RP, Shril S, Hildebrandt F

Abstract
BACKGROUND: Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of CKD. The discovery of monogenic causes of SRNS has revealed specific pathogenetic pathways, but these monogenic causes do not explain all cases of SRNS.
METHODS: To identify novel monogenic causes of SRNS, we screened 665 patients by whole-exome sequencing. We then evaluated the in vitro functional significance of two genes and the mutations therein that we discovered through this sequencing and conducted complementary studies in podocyte-like Drosophila nephrocytes.
RESULTS: We identified conserved, homozygous missense mutations of GAPVD1 in two families with early-onset NS and a homozygous missense mutation of ANKFY1 in two siblings with SRNS. GAPVD1 and ANKFY1 interact with the endosomal regulator RAB5. Coimmunoprecipitation assays indicated interaction between GAPVD1 and ANKFY1 proteins, which also colocalized when expressed in HEK293T cells. Silencing either protein diminished the podocyte migration rate. Compared with wild-type GAPVD1 and ANKFY1, the mutated proteins produced upon ectopic expression of GAPVD1 or ANKFY1 bearing the patient-derived mutations exhibited altered binding affinity for active RAB5 and reduced ability to rescue the knockout-induced defect in podocyte migration. Coimmunoprecipitation assays further demonstrated a physical interaction between nephrin and GAPVD1, and immunofluorescence revealed partial colocalization of these proteins in rat glomeruli. The patient-derived GAPVD1 mutations reduced nephrin-GAPVD1 binding affinity. In Drosophila, silencing Gapvd1 impaired endocytosis and caused mistrafficking of the nephrin ortholog.
CONCLUSIONS: Mutations in GAPVD1 and probably in ANKFY1 are novel monogenic causes of NS. The discovery of these genes implicates RAB5 regulation in the pathogenesis of human NS.

PMID: 29959197 [PubMed - as supplied by publisher]

High Throughput Sequencing and Assessing Disease Risk.

Cold Spring Harb Perspect Med. 2018 Jun 29;:

Authors: Rego SM, Snyder MP

Abstract
High-throughput sequencing has dramatically improved our ability to determine and diagnose the underlying causes of human disease. The use of whole-genome and whole-exome sequencing has facilitated faster and more cost-effective identification of new genes implicated in Mendelian disease. It has also improved our ability to identify disease-causing mutations for Mendelian diseases whose associated genes are already known. These benefits apply not only in cases in which the objective is to assess genetic disease risk in adults and children, but also for prenatal genetic testing and embryonic testing. High-throughput sequencing has also impacted our ability to assess risk for complex diseases and will likely continue to influence this area of disease research as more and more individuals undergo sequencing and we better understand the significance of variation, both rare and common, across the genome. Through these activities, high-throughput sequencing has the potential to revolutionize medicine.

PMID: 29959131 [PubMed - as supplied by publisher]

Mutational landscape of a chemically-induced mouse model of liver cancer.

J Hepatol. 2018 Jun 26;:

Authors: Connor F, Rayner TF, Aitken SJ, Feig C, Lukk M, Santoyo-Lopez J, Odom DT

Abstract
BACKGROUND AND AIMS: Carcinogen-induced mouse models of liver cancer are used extensively to study pathogenesis of the disease and have a critical role in validating candidate therapeutics. These models can recapitulate molecular and histological features of human disease. However, it is not known if the genomic alterations driving these mouse tumour genomes are comparable to those found in human tumours. Here, we provide a detailed genomic characterisation of tumours from a commonly used mouse model of hepatocellular carcinoma (HCC).
METHODS: We analysed whole exome sequences of liver tumours arising in mice exposed to diethylnitrosamine (DEN).
RESULTS: DEN-initiated tumours had a high, uniform number of somatic single nucleotide variants (SNVs), with few insertions, deletions or copy number alterations, consistent with the known genotoxic action of DEN. Exposure of hepatocytes to DEN left a reproducible mutational imprint in resulting tumour exomes which we could computationally reconstruct using six known COSMIC mutational signatures. The tumours carried a high diversity of low-incidence, non-synonymous point mutations in many oncogenes and tumour suppressors, reflecting the stochastic introduction of SNVs into the hepatocyte genome by the carcinogen. We identified four recurrently mutated genes that were putative oncogenic drivers of HCC in this model. Every neoplasm carried activating hotspot mutations either in codon 61 of Hras, in codon 584 of Braf or in codon 254 of Egfr. Truncating mutations of Apc occurred in 21% of neoplasms, which were exclusively carcinomas supporting a role for deregulation of Wnt/β-catenin signalling in cancer progression.
CONCLUSIONS: Our study provides detailed insight into the mutational landscape of tumours arising in a commonly-used carcinogen model of HCC, facilitating the future use of this model to understand the human disease.
LAY SUMMARY: Mouse models are widely used to study the biology of cancer and to test potential therapies. Here, we have described the mutational landscape of tumours arising in a carcinogen-induced mouse model of liver cancer. Since cancer is a disease caused by genomic alterations, information about the patterns and types of mutations in the tumours in this mouse model should facilitate its use to study human liver cancer.

PMID: 29958939 [PubMed - as supplied by publisher]

Autism and heritable bone fragility: A true association?

Bone Rep. 2018 Jun;8:156-162

Authors: Balasubramanian M, Jones R, Milne E, Marshall C, Arundel P, Smith K, Bishop NJ

Abstract
Objectives: Osteogenesis Imperfecta (OI) is a heterogeneous condition mainly characterised by bone fragility; intelligence is reported to be normal. However, a minority of children seen also show symptomology consistent with an 'Autism Spectrum Disorder'. A joint genetics and psychology research study was undertaken to identify these patients using 'Gold Standard' research tools: Autism Diagnostic Inventory Revised (ADI-R); Autism Diagnostic Observation Schedule (ADOS) and undertake genetic analyses in them.
Method: A cohort of n = 7 children with autistic traits and severe/complex OI were recruited to the study. The study was set-up to explore whether there was a genetic link between bone fragility and autism in a sub-set of patients with bone fragility identified with autism traits in our complex/severe OI clinic. This was not set-up as a prevalence study but rather an exploration of genetics in association with ADI/ADOS confirmed ASD and bone fragility.
ADI& ADOS: Standardised tools were used to confirm autism diagnosis. ADI and ADOS were completed by the Clinical Psychologist; ADI comprises a 93 item semi-structured clinical review with a diagnostic algorithm diagnosing Autism; ADOS is a semi-structured assessment of socialisation, communication and play/imagination which also provides a diagnostic algorithm.
Exome sequencing: In patients recruited, those that fulfilled research criteria for diagnosis of autism using above tools were recruited to trio whole exome sequencing (WES).
Results: one patient had compound heterozygous variants in NBAS; one patient had a variant in NRX1; one patient had a maternally inherited PLS3 variant; all the other patients in this cohort had pathogenic variants in COL1A1/COL1A2.
Conclusions: Although, not set out as an objective, we were able to establish that identifying autism had important clinical and social benefits for patients and their families in ensuring access to services, appropriate schooling, increased understanding of behaviour and support.
Lay summary: It is important for clinicians looking after children with brittle bone disease, also referred to as Osteogenesis Imperfecta (OI) to be aware of early features of developmental delay/autistic traits especially with severe forms of OI as the emphasis is on their mobility and bone health. Ensuring appropriate assessment and access to services early-on will enable these patients to achieve their potential. Further investigations of genomics in bone fragility in relation to autism are required and dual diagnosis is essential for high quality clinical and educational provision.

PMID: 29955634 [PubMed]

Congenital and acquired diseases related to stone formation.

Curr Opin Urol. 2018 Jun 27;:

Authors: Veser J, Özsoy M, Seitz C

Abstract
PURPOSE OF REVIEW: To summarize the latest findings of congenital and acquired diseases related to stone formation and help understanding the multitude of cofactors related to urolithiasis.
RECENT FINDINGS: Urolithiasis is related to a broad spectrum of congenital and acquired diseases and its management varies according to the stone type, underlying disease or recurrence rate, but it also changes according to recent findings and developments. As prevalence of urolithiasis is constantly increasing, identification of high-risk stone formers and early treatment is essential. Therefore, genetic evaluation like whole exome sequencing becomes a pertinent part of further diagnostics.
SUMMARY: Stone formation is a very heterogeneous pathomechanism. This prompt us to look at every patient individually particularly in high-risk patients, including stone and 24-h-urine analysis and additional diagnostic work-up based on stone type or underlying disease.

PMID: 29957682 [PubMed - as supplied by publisher]

Historical and Clinical Perspectives on Chromosomal Translocations.

Adv Exp Med Biol. 2018;1044:1-14

Authors: Wilch ES, Morton CC

Abstract
Chromosomal translocations, rearrangements involving the exchange of segments between chromosomes, were documented in humans in 1959. The first accurately reported clinical phenotype resulting from a translocation was that of Down syndrome. In a small percentage of Down syndrome cases, an extra 21q is provided by a Robertsonian translocation chromosome, either occurring de novo or inherited from a phenotypically normal parent with the translocation chromosome and a balanced genome of 45 chromosomes. Balanced translocations, including both Robertsonian and reciprocal translocations, are typically benign, but meiosis in germ cells with balanced translocations may result in meiotic arrest and subsequent infertility, or in unbalanced gametes, with attendant risks of miscarriage and unbalanced progeny. Most reciprocal translocations are unique. A few to several percent of translocations disrupt haploinsufficient genes or their regulatory regions and result in clinical phenotypes. Balanced translocations from patients with clinical phenotypes have been valuable in mapping disease genes and in illuminating cis-regulatory regions. Mapping of discordant mate pairs from long-insert, low-pass genome sequencing now permits efficient and cost-effective discovery and nucleotide-level resolution of rearrangement breakpoints, information that is absolutely necessary for interpreting the etiology of clinical phenotypes in patients with rearrangements. Pathogenic translocations and other balanced chromosomal rearrangements constitute a class of typically highly penetrant mutation that is cryptic to both clinical microarray and exome sequencing. A significant proportion of rearrangements include additional complexity that is not visible by conventional karyotype analysis. Some proportion of patients with negative findings on exome/genome sequencing and clinical microarray will be found to have etiologic balanced rearrangements only discoverable by genome sequencing with analysis pipelines optimized to recover rearrangement breakpoints.

PMID: 29956287 [PubMed - in process]

Comprehensive genetic testing in children with a clinical diagnosis of ARPKD identifies phenocopies.

Pediatr Nephrol. 2018 Jun 28;:

Authors: Szabó T, Orosz P, Balogh E, Jávorszky E, Máttyus I, Bereczki C, Maróti Z, Kalmár T, Szabó AJ, Reusz G, Várkonyi I, Marián E, Gombos É, Orosz O, Madar L, Balla G, Kappelmayer J, Tory K, Balogh I

Abstract
BACKGROUND: Autosomal recessive polycystic kidney disease (ARPKD) is genetically one of the least heterogeneous ciliopathies, resulting primarily from mutations of PKHD1. Nevertheless, 13-20% of patients diagnosed with ARPKD are found not to carry PKHD1 mutations by sequencing. Here, we assess whether PKHD1 copy number variations or second locus mutations explain these cases.
METHODS: Thirty-six unrelated patients with the clinical diagnosis of ARPKD were screened for PKHD1 point mutations and copy number variations. Patients without biallelic mutations were re-evaluated and screened for second locus mutations targeted by the phenotype, followed, if negative, by clinical exome sequencing.
RESULTS: Twenty-eight patients (78%) carried PKHD1 point mutations, three of whom on only one allele. Two of the three patients harbored in trans either a duplication of exons 33-35 or a large deletion involving exons 1-55. All eight patients without PKHD1 mutations (22%) harbored mutations in other genes (PKD1 (n = 2), HNF1B (n = 3), NPHP1, TMEM67, PKD1/TSC2). Perinatal respiratory failure, a kidney length > +4SD and early-onset hypertension increase the likelihood of PKHD1-associated ARPKD. A patient compound heterozygous for a second and a last exon truncating PKHD1 mutation (p.Gly4013Alafs*25) presented with a moderate phenotype, indicating that fibrocystin is partially functional in the absence of its C-terminal 62 amino acids.
CONCLUSIONS: We found all ARPKD cases without PKHD1 point mutations to be phenocopies, and none to be explained by biallelic PKHD1 copy number variations. Screening for copy number variations is recommended in patients with a heterozygous point mutation.

PMID: 29956005 [PubMed - as supplied by publisher]

Genomic ERBB2/ERBB3 mutations promote PD-L1-mediated immune escape in gallbladder cancer: a whole-exome sequencing analysis.

Gut. 2018 Jun 28;:

Authors: Li M, Liu F, Zhang F, Zhou W, Jiang X, Yang Y, Qu K, Wang Y, Ma Q, Wang T, Bai L, Wang Z, Song X, Zhu Y, Yuan R, Gao Y, Liu Y, Jin Y, Li H, Xiang S, Ye Y, Zhang Y, Jiang L, Hu Y, Hao Y, Lu W, Chen S, Gu J, Zhou J, Gong W, Zhang Y, Wang X, Liu X, Liu C, Liu H, Liu Y, Liu Y

Abstract
OBJECTIVES: Patients with gallbladder carcinoma (GBC) lack effective treatment methods largely due to the inadequacy of both molecular characterisation and potential therapeutic targets. We previously uncovered a spectrum of genomic alterations and identified recurrent mutations in the ErbB pathway in GBC. Here, we aimed to study recurrent mutations of genes and pathways in a larger cohort of patients with GBC and investigate the potential mechanisms and clinical significance of these mutations.
DESIGN: We performed whole-exome sequencing (WES) in 157 patients with GBC. Functional experiments were applied in GBC cell lines to explore the oncogenic roles of ERBB2/ERBB3 hotspot mutations, their correlation with PD-L1 expression and the underlying mechanisms. ERBB inhibitors and a PD-L1 blocker were used to evaluate the anticancer activities in co-culture systems in vitro and in vivo.
RESULTS: WES identified ERBB2 and ERBB3 mutations at a frequency of 7%-8% in the expanded cohort, and patients with ERBB2/ERBB3 mutations exhibited poorer prognoses. A set of in vitro and in vivo experiments revealed increased proliferation/migration on ERBB2/ERBB3 mutation. Ectopic expression of ERBB2/ERBB3 mutants upregulated PD-L1 expression in GBC cells, effectively suppressed normal T-cell-mediated cytotoxicity in vitro through activation of the PI3K/Akt signalling pathway and contributed to the growth and progression of GBC in vivo. Treatment with an ERBB2/ERBB3 inhibitor or a PD-L1 monoclonal antibody reversed these immunosuppressive effects, and combined therapy revealed promising therapeutic activities.
CONCLUSIONS: ERBB2/ERBB3 mutations may serve as useful biomarkers in identifying patients who are sensitive to ERBB2/ERBB3 inhibitors and PD-L1 monoclonal antibody treatment.
TRIAL REGISTRATION NUMBER: NCT 02442414;Pre-results.

PMID: 29954840 [PubMed - as supplied by publisher]

Analysis of Circulating Cell-Free DNA Identifies Multiclonal Heterogeneity of BRCA2 Reversion Mutations Associated with Resistance to PARP Inhibitors.

Cancer Discov. 2017 09;7(9):999-1005

Authors: Quigley D, Alumkal JJ, Wyatt AW, Kothari V, Foye A, Lloyd P, Aggarwal R, Kim W, Lu E, Schwartzman J, Beja K, Annala M, Das R, Diolaiti M, Pritchard C, Thomas G, Tomlins S, Knudsen K, Lord CJ, Ryan C, Youngren J, Beer TM, Ashworth A, Small EJ, Feng FY

Abstract
Approximately 20% of metastatic prostate cancers harbor mutations in genes required for DNA repair by homologous recombination repair (HRR) such as BRCA2 HRR defects confer synthetic lethality to PARP inhibitors (PARPi) such as olaparib and talazoparib. In ovarian or breast cancers, olaparib resistance has been associated with HRR restoration, including by BRCA2 mutation reversion. Whether similar mechanisms operate in prostate cancer, and could be detected in liquid biopsies, is unclear. Here, we identify BRCA2 reversion mutations associated with olaparib and talazoparib resistance in patients with prostate cancer. Analysis of circulating cell-free DNA (cfDNA) reveals reversion mutation heterogeneity not discernable from a single solid-tumor biopsy and potentially allows monitoring for the emergence of PARPi resistance.Significance: The mechanisms of clinical resistance to PARPi in DNA repair-deficient prostate cancer have not been described. Here, we show BRCA2 reversion mutations in patients with prostate cancer with metastatic disease who developed resistance to talazoparib and olaparib. Furthermore, we show that PARPi resistance is highly multiclonal and that cfDNA allows monitoring for PARPi resistance. Cancer Discov; 7(9); 999-1005. ©2017 AACR.See related commentary by Domchek, p. 937See related article by Kondrashova et al., p. 984See related article by Goodall et al., p. 1006This article is highlighted in the In This Issue feature, p. 920.

PMID: 28450426 [PubMed - indexed for MEDLINE]

The role of UNC5C in Alzheimer's disease.

Ann Transl Med. 2018 May;6(10):178

Authors: Li Q, Wang BL, Sun FR, Li JQ, Cao XP, Tan L

Abstract
Alzheimer's disease (AD) is a chronic progressive neurodegenerative disease in adults characterized by the deposition of extracellular plaques of β-amyloid protein (Aβ), intracellular neurofibrillary tangles (NFTs), synaptic loss and neuronal apoptosis. AD has a strong and complex genetic component that involving into multiple genes. With recent advances in whole-exome sequencing (WES) and whole-genome sequencing (WGS) technology, UNC5C was identified to have association with AD. Emerging studies on cell and animal models identified that aberrant UNC5C may contribute to AD by activating death-associated protein kinase 1 (DAPK1) which is a new component involved in AD pathogenesis with an extensive involvement in aberrant tau, Aβ and neuronal apoptosis/autophagy. In this review, we briefly summarize the biochemical properties, genetics, epigenetics, and the speculative role of UNC5C in AD. We hope our review would bring comprehensive understandings of AD pathogenesis and provide new therapeutic targets for AD.

PMID: 29951500 [PubMed]

Mutant cytoskeletal and ECM peptides sensitive to the ST14 protease are associated with a worse outcome for glioblastoma multiforme.

Biochem Biophys Res Commun. 2018 Jun 25;:

Authors: Zaman S, Chobrutskiy BI, Patel JS, Callahan BM, Tong WL, Blanck G

Abstract
We previously identified a set of the most frequently mutated cytoskeleton- and extracellular matrix-related proteins (CECMPs) in numerous cancer datasets. In this report, we used a bioinformatics approach to assess the impact of amino acid (AA) substitutions on the sensitivity of CECMPs to the ST14 protease (matriptase I), a transmembrane serine protease previously implicated in cancer development. Results indicated that AA substitutions in glioblastoma multiforme (GBM) CECMPs are skewed toward increased resistance to the ST14 protease, in comparison to the wild-type peptide sequence. Furthermore, the protease resistant AA substitutions represent relatively high binding affinities to HLA class I proteins, when assessing the binding specificities using HLA class I alleles matched to the source of the mutant AA. Moreover, samples representing AA substitutions that increased protease sensitivity also represented reduced overall and disease-free survival periods for patients with glioblastoma. To assess tumor specimen immunogenicity, we identified T-cell receptor (TCR) V(D)J recombinations in GBM exome files. The overlap between ST14 protease sensitive mutant barcodes and the TCR V(D)J recombination read positive barcodes represented significantly reduced survival.

PMID: 29953855 [PubMed - as supplied by publisher]

KMT2D/MLL2 inactivation is associated with recurrence in adult-type granulosa cell tumors of the ovary.

Nat Commun. 2018 Jun 27;9(1):2496

Authors: Hillman RT, Celestino J, Terranova C, Beird HC, Gumbs C, Little L, Nguyen T, Thornton R, Tippen S, Zhang J, Lu KH, Gershenson DM, Rai K, Broaddus RR, Futreal PA

Abstract
Adult-type granulosa cell tumors of the ovary (aGCTs) are rare gynecologic malignancies that exhibit a high frequency of somatic FOXL2 c.C402G (p.Cys134Trp) mutation. Treatment of relapsed aGCT remains a significant clinical challenge. Here we show, using whole-exome and cancer gene panel sequencing of 79 aGCTs from two independent cohorts, that truncating mutation of the histone lysine methyltransferase gene KMT2D (also known as MLL2) is a recurrent somatic event in aGCT. Mono-allelic KMT2D-truncating mutations are more frequent in recurrent (10/44, 23%) compared with primary (1/35, 3%) aGCTs (p = 0.02, two-sided Fisher's exact test). IHC detects additional non-KMT2D-mutated aGCTs with loss of nuclear KMT2D expression, suggesting that non-genetic KMT2D inactivation may occur in this tumor type. These findings identify KMT2D inactivation as a novel driver event in aGCTs and suggest that mutation of this gene may increase the risk of disease recurrence.

PMID: 29950560 [PubMed - in process]

Mutational analysis identifies therapeutic biomarkers in inflammatory bowel disease-associated colorectal cancers.

Clin Cancer Res. 2018 Jun 27;:

Authors: Din S, Wong K, Müller MF, Oniscu A, Hewinson J, Black CJ, Miller ML, Jiménez-Sánchez A, Rabbie R, Rashid M, Satsangi J, Adams DJ, Arends MJ

Abstract
PURPOSE: Inflammatory bowel disease-associated colorectal cancers (IBD-CRCs) are associated with a higher mortality than sporadic colorectal cancers. The poorly defined molecular pathogenesis of IBD-CRCs limits development of effective prevention, detection and treatment strategies. We aimed to identify biomarkers using whole exome sequencing of IBD-CRCs to guide individualised management.
EXPERIMENTAL DESIGN: Whole-exome sequencing was performed on 34 formalin-fixed paraffin-embedded primary IBD-CRCs and 31 matched normal lymph nodes. Computational methods were used to identify somatic point mutations, small insertions and deletions, mutational signatures, and somatic copy number alterations. Mismatch repair status was examined.
RESULTS: Hypermutation was observed in 27% of IBD-CRCs. All hypermutated cancers were from the proximal colon; all but 1 of the cancers with hypermutation had defective mismatch repair or somatic mutations in the proofreading domain of DNA POLE Hypermutated IBD-CRCs had increased numbers of predicted neo-epitopes, which could be exploited using immunotherapy. We identified 6 distinct mutation signatures in IBD-CRCs, 3 of which corresponded with known mechanisms of mutagenesis. Driver genes were also identified.
CONCLUSIONS: IBD-CRCs should be evaluated for hypermutation and defective mismatch repair to identify patients with a higher neo-epitope load who may benefit from immunotherapies. Prospective trials are required to determine whether immunohistochemistry to detect loss of MLH1 expression in dysplastic colonic tissue could identify patients at increased risk of developing IBD-CRC. We identified mutations in genes in IBD-CRCs with hypermutation that might be targeted therapeutically. These approaches would complement and individualise surveillance and treatment programmes.

PMID: 29950348 [PubMed - as supplied by publisher]

Advancing genomic approaches to the molecular diagnosis of mitochondrial disease.

Essays Biochem. 2018 Jun 27;:

Authors: Stenton SL, Prokisch H

Abstract
Mitochondrial diseases present a diagnostic challenge due to their clinical and genetic heterogeneity. Achieving comprehensive molecular diagnosis via a conventional candidate-gene approach is likely, therefore, to be labour- and cost-intensive given the expanding number of mitochondrial disease genes. The advent of whole exome sequencing (WES) and whole genome sequencing (WGS) hold the potential of higher diagnostic yields due to the universality and unbiased nature of the methods. However, these approaches are subject to the escalating challenge of variant interpretation. Thus, integration of functional 'multi-omics' data, such as transcriptomics, is emerging as a powerful complementary tool in the diagnosis of mitochondrial disease patients for whom extensive prior analysis of DNA sequencing has failed to return a genetic diagnosis.

PMID: 29950319 [PubMed - as supplied by publisher]

Association Between Inherited Germline Mutations in Cancer Predisposition Genes and Risk of Pancreatic Cancer.

JAMA. 2018 06 19;319(23):2401-2409

Authors: Hu C, Hart SN, Polley EC, Gnanaolivu R, Shimelis H, Lee KY, Lilyquist J, Na J, Moore R, Antwi SO, Bamlet WR, Chaffee KG, DiCarlo J, Wu Z, Samara R, Kasi PM, McWilliams RR, Petersen GM, Couch FJ

Abstract
Importance: Individuals genetically predisposed to pancreatic cancer may benefit from early detection. Genes that predispose to pancreatic cancer and the risks of pancreatic cancer associated with mutations in these genes are not well defined.
Objective: To determine whether inherited germline mutations in cancer predisposition genes are associated with increased risks of pancreatic cancer.
Design, Setting, and Participants: Case-control analysis to identify pancreatic cancer predisposition genes; longitudinal analysis of patients with pancreatic cancer for prognosis. The study included 3030 adults diagnosed as having pancreatic cancer and enrolled in a Mayo Clinic registry between October 12, 2000, and March 31, 2016, with last follow-up on June 22, 2017. Reference controls were 123 136 individuals with exome sequence data in the public Genome Aggregation Database and 53 105 in the Exome Aggregation Consortium database.
Exposures: Individuals were classified based on carrying a deleterious mutation in cancer predisposition genes and having a personal or family history of cancer.
Main Outcomes and Measures: Germline mutations in coding regions of 21 cancer predisposition genes were identified by sequencing of products from a custom multiplex polymerase chain reaction-based panel; associations of genes with pancreatic cancer were assessed by comparing frequency of mutations in genes of pancreatic cancer patients with those of reference controls.
Results: Comparing 3030 case patients with pancreatic cancer (43.2% female; 95.6% non-Hispanic white; mean age at diagnosis, 65.3 [SD, 10.7] years) with reference controls, significant associations were observed between pancreatic cancer and mutations in CDKN2A (0.3% of cases and 0.02% of controls; odds ratio [OR], 12.33; 95% CI, 5.43-25.61); TP53 (0.2% of cases and 0.02% of controls; OR, 6.70; 95% CI, 2.52-14.95); MLH1 (0.13% of cases and 0.02% of controls; OR, 6.66; 95% CI, 1.94-17.53); BRCA2 (1.9% of cases and 0.3% of controls; OR, 6.20; 95% CI, 4.62-8.17); ATM (2.3% of cases and 0.37% of controls; OR, 5.71; 95% CI, 4.38-7.33); and BRCA1 (0.6% of cases and 0.2% of controls; OR, 2.58; 95% CI, 1.54-4.05).
Conclusions and Relevance: In this case-control study, mutations in 6 genes associated with pancreatic cancer were found in 5.5% of all pancreatic cancer patients, including 7.9% of patients with a family history of pancreatic cancer and 5.2% of patients without a family history of pancreatic cancer. Further research is needed for replication in other populations.

PMID: 29922827 [PubMed - indexed for MEDLINE]

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