Dysfunction of the Voltage-Gated K+ Channel β2 Subunit in a Familial Case of Brugada Syndrome.

J Am Heart Assoc. 2016 Jun 10;5(6):

Authors: Portero V, Le Scouarnec S, Es-Salah-Lamoureux Z, Burel S, Gourraud JB, Bonnaud S, Lindenbaum P, Simonet F, Violleau J, Baron E, Moreau E, Scott C, Chatel S, Loussouarn G, O'Hara T, Mabo P, Dina C, Le Marec H, Schott JJ, Probst V, Baró I, Marionneau C, Charpentier F, Redon R

Abstract
BACKGROUND: The Brugada syndrome is an inherited cardiac arrhythmia associated with high risk of sudden death. Although 20% of patients with Brugada syndrome carry mutations in SCN5A, the molecular mechanisms underlying this condition are still largely unknown.
METHODS AND RESULTS: We combined whole-exome sequencing and linkage analysis to identify the genetic variant likely causing Brugada syndrome in a pedigree for which SCN5A mutations had been excluded. This approach identified 6 genetic variants cosegregating with the Brugada electrocardiographic pattern within the pedigree. In silico gene prioritization pointed to 1 variant residing in KCNAB2, which encodes the voltage-gated K(+) channel β2-subunit (Kvβ2-R12Q). Kvβ2 is widely expressed in the human heart and has been shown to interact with the fast transient outward K(+) channel subunit Kv4.3, increasing its current density. By targeted sequencing of the KCNAB2 gene in 167 unrelated patients with Brugada syndrome, we found 2 additional rare missense variants (L13F and V114I). We then investigated the physiological effects of the 3 KCNAB2 variants by using cellular electrophysiology and biochemistry. Patch-clamp experiments performed in COS-7 cells expressing both Kv4.3 and Kvβ2 revealed a significant increase in the current density in presence of the R12Q and L13F Kvβ2 mutants. Although biotinylation assays showed no differences in the expression of Kv4.3, the total and submembrane expression of Kvβ2-R12Q were significantly increased in comparison with wild-type Kvβ2.
CONCLUSIONS: Altogether, our results indicate that Kvβ2 dysfunction can contribute to the Brugada electrocardiographic pattern.

PMID: 27287695 [PubMed - indexed for MEDLINE]

[Trends and expectations the research on the molecular background of epileptic encephalopathies - state of the art in 2017].

Dev Period Med. 2017;21(4):317-327

Authors: Hoffman-Zacharska D, Górka-Skoczylas P

Abstract
Epilepsy is common neurological condition affecting 0.8-1% of the human population. Since 80% of patients are under 20 years of age, it is mainly a disease of the developmental period. The causes of epilepsy are heterogeneous, but the disease has always been considered a genetic disorder, which no longer doubted. Epilepsy genetics has undergone a revolution since the discovery of the first gene responsible for epilepsy. This is mainly because of introduction of the next generation sequencing as research and diagnostic tool, and transition from studies of pedigrees with epilepsy to the analysis of cases of epileptic encephalopathies. In a short time more than 50 early infantile epileptic encephalopathies were recognized due to the causative genes. Whole exome or targeted panel sequencing has been used as a diagnostic tool with a diagnostic yield of about 30-40%. The "genetic diagnosis" that is obtained makes it possible to introduce targeted treatment in an increasing number of cases. Since epileptic encephalopaties are often regarded as the model disease for epilepsy, these therapeutic strategies can provide treatment for patients with common epilepsies.

PMID: 29291359 [PubMed - in process]

Recurrent ECSIT mutation encoding V140A triggers hyperinflammation and promotes hemophagocytic syndrome in extranodal NK/T cell lymphoma.

Nat Med. 2018 Jan 01;:

Authors: Wen H, Ma H, Cai Q, Lin S, Lei X, He B, Wu S, Wang Z, Gao Y, Liu W, Liu W, Tao Q, Long Z, Yan M, Li D, Kelley KW, Yang Y, Huang H, Liu Q

Abstract
Hemophagocytic syndrome (HPS) is a fatal hyperinflammatory disease with a poorly understood mechanism that occurs most frequently in extranodal natural killer/T cell lymphoma (ENKTL). Through exome sequencing of ENKTL tumor-normal samples, we have identified a hotspot mutation (c.419T>C) in the evolutionarily conserved signaling intermediate in Toll pathway (ECSIT) gene, encoding a V140A variant of ECSIT. ECSIT-V140A activated NF-κB more potently than the wild-type protein owing to its increased affinity for the S100A8 and S100A9 heterodimer, which promotes NADPH oxidase activity. ECSIT-T419C knock-in mice showed higher peritoneal NADPH oxidase activity than mice with wild-type ECSIT in response to LPS. ECSIT-T419C-transfected ENKTL cell lines produced tumor necrosis factor (TNF)-α and interferon (IFN)-γ, which induced macrophage activation and massive cytokine secretion in cell culture and mouse xenografts. In individuals with ENKTL, ECSIT-V140A was associated with activation of NF-κB, higher HPS incidence, and poor prognosis. The immunosuppressive drug thalidomide prevented NF-κB from binding to the promoters of its target genes (including TNF and IFNG), and combination treatment with thalidomide and dexamethasone extended survival of mice engrafted with ECSIT-T419C-transfected ENKTL cells. We added thalidomide to the conventional dexamethasone-containing therapy regimen for two patients with HPS who expressed ECSIT-V140A, and we observed reversal of their HPS and disease-free survival for longer than 3 years. These findings provide mechanistic insights and a potential therapeutic strategy for ENKTL-associated HPS.

PMID: 29291352 [PubMed - as supplied by publisher]

Whole exome sequencing identifies novel mutation in eight Chinese children with isolated tetralogy of Fallot.

Oncotarget. 2017 Dec 05;8(63):106976-106988

Authors: Liu L, Wang HD, Cui CY, Qin YY, Fan TB, Peng BT, Zhang LZ, Wang CZ

Abstract
Background: Tetralogy of Fallot is the most common cyanotic congenital heart disease. However, its pathogenesis remains to be clarified. The purpose of this study was to identify the genetic variants in Tetralogy of Fallot by whole exome sequencing.
Methods: Whole exome sequencing was performed among eight small families with Tetralogy of Fallot. Differential single nucleotide polymorphisms and small InDels were found by alignment within families and between families and then were verified by Sanger sequencing. Tetralogy of Fallot-related genes were determined by analysis using Gene Ontology /pathway, Online Mendelian Inheritance in Man, PubMed and other databases.
Results: A total of sixteen differential single nucleotide polymorphisms loci and eight differential small InDels were discovered. The sixteen differential single nucleotide polymorphisms loci were located on Chr 1, 2, 4, 5, 11, 12, 15, 22 and X. Among the sixteen single nucleotide polymorphisms loci, six has not been reported. The eight differential small InDels were located on Chr 2, 4, 9, 12, 17, 19 and X, whereas of the eight differential small InDels, two has not been reported. Analysis using Gene Ontology /pathway, Online Mendelian Inheritance in Man, PubMed and other databases revealed that PEX5, NACA, ATXN2, CELA1, PCDHB4 and CTBP1 were associated with Tetralogy of Fallot.
Conclusions: Our findings identify PEX5, NACA, ATXN2, CELA1, PCDHB4 and CTBP1 mutations as underlying genetic causes of isolated tetralogy of Fallot.

PMID: 29291004 [PubMed]

Construction of an Exome-Wide Risk Score for Schizophrenia Based on a Weighted Burden Test.

Ann Hum Genet. 2018 Jan;82(1):11-22

Authors: Curtis D

Abstract
Polygenic risk scores obtained as a weighted sum of associated variants can be used to explore association in additional data sets and to assign risk scores to individuals. The methods used to derive polygenic risk scores from common SNPs are not suitable for variants detected in whole exome sequencing studies. Rare variants, which may have major effects, are seen too infrequently to judge whether they are associated and may not be shared between training and test subjects. A method is proposed whereby variants are weighted according to their frequency, their annotations and the genes they affect. A weighted sum across all variants provides an individual risk score. Scores constructed in this way are used in a weighted burden test and are shown to be significantly different between schizophrenia cases and controls using a five-way cross-validation procedure. This approach represents a first attempt to summarise exome sequence variation into a summary risk score, which could be combined with risk scores from common variants and from environmental factors. It is hoped that the method could be developed further.

PMID: 28895126 [PubMed - indexed for MEDLINE]

Whole-exome sequencing identifies an α-globin cluster triplication resulting in increased clinical severity of β-thalassemia.

Cold Spring Harb Mol Case Stud. 2017 Nov;3(6):

Authors: Steinberg-Shemer O, Ulirsch JC, Noy-Lotan S, Krasnov T, Attias D, Dgany O, Laor R, Sankaran VG, Tamary H

Abstract
Whole-exome sequencing (WES) has been increasingly useful for the diagnosis of patients with rare causes of anemia, particularly when there is an atypical clinical presentation or targeted genotyping approaches are inconclusive. Here, we describe a 20-yr-old man with a lifelong moderate-to-severe anemia with accompanying splenomegaly who lacked a definitive diagnosis. After a thorough clinical workup and targeted genetic sequencing, we identified a paternally inherited β-globin mutation (HBB:c.93-21G>A, IVS-I-110:G>A), a known cause of β-thalassemia minor. As this mutation alone was inconsistent with the severity of the anemia, we performed WES. Although we could not identify any relevant pathogenic single-nucleotide variants (SNVs) or small indels, copy-number variant (CNV) analyses revealed a likely triplication of the entire α-globin cluster, which was subsequently confirmed by multiplex ligation-dependent probe amplification. Treatment and follow-up was redefined according to the diagnosis of β-thalassemia intermedia resulting from a single β-thalassemia mutation in combination with an α-globin cluster triplication. Thus, we describe a case where the typical WES-based analysis of SNVs and small indels was unrevealing, but WES-based CNV analysis resulted in a definitive diagnosis that informed clinical decision-making. More generally, this case illustrates the value of performing CNV analysis when WES is otherwise unable to elucidate a clear genetic diagnosis.

PMID: 28667000 [PubMed - indexed for MEDLINE]

Understanding Neurodevelopmental Disorders: The Promise of Regulatory Variation in the 3'UTRome.

Biol Psychiatry. 2017 Nov 14;:

Authors: Wanke KA, Devanna P, Vernes SC

Abstract
Neurodevelopmental disorders have a strong genetic component, but despite widespread efforts, the specific genetic factors underlying these disorders remain undefined for a large proportion of affected individuals. Given the accessibility of exome sequencing, this problem has thus far been addressed from a protein-centric standpoint; however, protein-coding regions only make up ∼1% to 2% of the human genome. With the advent of whole genome sequencing we are in the midst of a paradigm shift as it is now possible to interrogate the entire sequence of the human genome (coding and noncoding) to fill in the missing heritability of complex disorders. These new technologies bring new challenges, as the number of noncoding variants identified per individual can be overwhelming, making it prudent to focus on noncoding regions of known function, for which the effects of variation can be predicted and directly tested to assess pathogenicity. The 3'UTRome is a region of the noncoding genome that perfectly fulfills these criteria and is of high interest when searching for pathogenic variation related to complex neurodevelopmental disorders. Herein, we review the regulatory roles of the 3'UTRome as binding sites for microRNAs or RNA binding proteins, or during alternative polyadenylation. We detail existing evidence that these regions contribute to neurodevelopmental disorders and outline strategies for identification and validation of novel putatively pathogenic variation in these regions. This evidence suggests that studying the 3'UTRome will lead to the identification of new risk factors, new candidate disease genes, and a better understanding of the molecular mechanisms contributing to neurodevelopmental disorders.

PMID: 29289333 [PubMed - as supplied by publisher]

Sequencing of Linkage Region on Chromosome 12p11 Identifies PKP2 as a Candidate Gene for Left Ventricular Mass in Dominican Families.

G3 (Bethesda). 2017 Dec 29;:

Authors: Dueker ND, Guo S, Beecham A, Wang L, Blanton SH, Di Tullio MR, Rundek T, Sacco RL

Abstract
Increased left ventricular mass (LVM) is an intermediate phenotype for cardiovascular disease (CVD) and a predictor of stroke. Using families from the Dominican Republic, we have previously shown LVM to be heritable and found evidence for linkage to chromosome 12p11. Our current study aimed to further characterize the QTL by sequencing the 1 LOD unit down region in ten families from the Dominican Republic with evidence for linkage to LVM. Within this region, we tested 5,477 common variants (CVs; minor allele frequency [MAF] ≥5%) using the QTDT test. Gene-based analyses were performed to test rare variants (RVs; MAF<5%) in 181 genes using the family-based sequence kernel association test. A sample of 618 unrelated Dominicans from the Northern Manhattan Study (NOMAS) and 12 Dominican families with Exome Array data were used for replication analyses. The most strongly associated CV with evidence for replication was rs1046116 (Discovery families p=9.0x10-4; NOMAS p=0.03; replication families p=0.46), a missense variant in PKP2 In non-synonymous RV analyses, PKP2 was one of the most strongly associated genes (p=0.05) with suggestive evidence for replication in NOMAS (p=0.05). PKP2 encodes the plakophilin 2 protein and is a desmosomal gene implicated in arrythmogenic right ventricular cardiomyopathy and recently in arrhythmogenic left ventricular cardiomyopathy, which makes PKP2 an excellent candidate gene for LVM. In conclusion, sequencing of our previously reported QTL identified common and rare variants within PKP2 to be associated with LVM. Future studies are necessary to elucidate the role these variants play in influencing LVM.

PMID: 29288195 [PubMed - as supplied by publisher]

A novel splicing mutation in SMPX is linked to nonsyndromic progressive hearing loss.

Int J Pediatr Otorhinolaryngol. 2018 Jan;104:47-50

Authors: Niu Z, Yan D, Bressler S, Mei L, Feng Y, Liu X

Abstract
OBJECTIVE: X-linked nonsyndromic hearing impairment is the rarest form of genetic hearing loss and represents only a minor fraction of all cases. The aim of this study was to investigate the cause of X-linked nonsyndromic sensorineural hearing loss in a three-generation American family.
METHODS: Whole-exome sequencing and co-segregation analysis were used to identify disease-causing genes.
RESULTS: In this study, we described in detail the clinical characteristics of the family and identified a novel frameshift mutation creating a premature stop codon (c.133-1 G > A, p.(Gly45fs*36)) of SMPX. The loss-of-function mutation was co-segregated with the progressive hearing loss phenotype and was absent in 200 normal controls.
CONCLUSIONS: We report the first SMPX (DFNX4) mutation in a North American family. Our findings contribute to the existing genotypic and phenotypic spectrum of SMPX associated hearing loss. Furthermore, our data suggest that exome sequencing is promising in the genetic diagnosis of hearing loss.

PMID: 29287879 [PubMed - in process]

SLC52A2 mutations cause SCABD2 phenotype: A second report.

Int J Pediatr Otorhinolaryngol. 2018 Jan;104:195-199

Authors: Babanejad M, Adeli OA, Nikzat N, Beheshtian M, Azarafra H, Sadeghnia F, Mohseni M, Najmabadi H, Kahrizi K

Abstract
INTRODUCTION: Autosomal recessive cerebellar ataxias (ARCAs) are a large group of neurodegenerative disorders that manifest mainly in children and young adults. Most ARCAs are heterogeneous with respect to age at onset, severity of disease progression, and frequency of extracerebellar and systemic signs.
METHODS: The phenotype of a consanguineous Iranian family was characterized using clinical testing and pedigree analysis. Whole-exome sequencing was used to identify the disease-causing gene in this family.
RESULTS AND CONCLUSION: Using whole exome sequencing (WES), a novel missense mutation in SLC52A2 gene is reported in a consanguineous Iranian family with progressive severe hearing loss, optic atrophy and ataxia. This is the second report of the genotype-phenotype correlation between this syndrome named spinocerebellar ataxia with blindness and deafness type 2 (SCABD2) and SLC52A2 gene.

PMID: 29287867 [PubMed - in process]

A possible role of FANCM mutations in male breast cancer susceptibility: Results from a multicenter study in Italy.

Breast. 2017 Dec 26;38:92-97

Authors: Silvestri V, Rizzolo P, Zelli V, Valentini V, Zanna I, Bianchi S, Tibiletti MG, Varesco L, Russo A, Tommasi S, Coppa A, Capalbo C, Calistri D, Viel A, Cortesi L, Manoukian S, Bonanni B, Montagna M, Palli D, Radice P, Peterlongo P, Ottini L

Abstract
INTRODUCTION: Breast cancer (BC) in men is a rare disease, whose etiology appears to be associated with genetic factors. Inherited mutations in BRCA1/2 genes account for about 10-15% of all cases. FANCM, functionally linked to BRCA1/2, has been suggested as a novel BC susceptibility gene. Our aim was to test if FANCM germline mutations could further explain male BC (MBC) susceptibility.
METHODS: We screened the entire coding region of FANCM in 286 MBCs by a multi-gene panel analysis, and compared these data with available whole exome sequencing data from 415 men used as population controls. Moreover, we genotyped the two most frequent FANCM mutations (c.5101C>T and c.5791C>T) in 506 MBCs and 854 healthy male controls.
RESULTS: Two FANCM truncating mutations, the c.1432C>T (p.Arg478Ter) and c.1972C>T (p.Arg658Ter), were identified in two MBC cases (0.7%). When specifically considering cases at increased genetic risk for BC, FANCM mutation frequency raises up to 1%. One mutation, the c.2201_2202delCT (p.Ser734Terfs), was found among controls (0.24%). Mutation frequency in cases was higher than in controls, however this difference was not statistically significant. FANCM c.5101C>T was not present in any of the cases and controls analyzed, whereas FANCM c.5791C>T was found in two controls (0.23%).
CONCLUSION: Rare FANCM truncating mutations, other than c.5101C>T and c.5791C>T, may have a role in MBC susceptibility. The inclusion of FANCM in gene panels for research purpose would allow for the identification of a higher number of mutation carriers, thus helping estimate BC risk associated with FANCM mutations.

PMID: 29287190 [PubMed - as supplied by publisher]

CELSR2 is a candidate susceptibility gene in idiopathic scoliosis.

PLoS One. 2017;12(12):e0189591

Authors: Einarsdottir E, Grauers A, Wang J, Jiao H, Escher SA, Danielsson A, Simony A, Andersen M, Christensen SB, Åkesson K, Kou I, Khanshour AM, Ohlin A, Wise C, Ikegawa S, Kere J, Gerdhem P

Abstract
A Swedish pedigree with an autosomal dominant inheritance of idiopathic scoliosis was initially studied by genetic linkage analysis, prioritising genomic regions for further analysis. This revealed a locus on chromosome 1 with a putative risk haplotype shared by all affected individuals. Two affected individuals were subsequently exome-sequenced, identifying a rare, non-synonymous variant in the CELSR2 gene. This variant is rs141489111, a c.G6859A change in exon 21 (NM_001408), leading to a predicted p.V2287I (NP_001399.1) change. This variant was found in all affected members of the pedigree, but showed reduced penetrance. Analysis of tagging variants in CELSR1-3 in a set of 1739 Swedish-Danish scoliosis cases and 1812 controls revealed significant association (p = 0.0001) to rs2281894, a common synonymous variant in CELSR2. This association was not replicated in case-control cohorts from Japan and the US. No association was found to variants in CELSR1 or CELSR3. Our findings suggest a rare variant in CELSR2 as causative for idiopathic scoliosis in a family with dominant segregation and further highlight common variation in CELSR2 in general susceptibility to idiopathic scoliosis in the Swedish-Danish population. Both variants are located in the highly conserved GAIN protein domain, which is necessary for the auto-proteolysis of CELSR2, suggesting its functional importance.

PMID: 29240829 [PubMed - indexed for MEDLINE]

Congenital Neuronal Ceroid Lipofuscinosis with a Novel CTSD Gene Mutation: A Rare Cause of Neonatal-Onset Neurodegenerative Disorder.

Neuropediatrics. 2017 Dec 28;:

Authors: Varvagiannis K, Hanquinet S, Billieux MH, De Luca R, Rimensberger P, Lidgren M, Guipponi M, Makrythanasis P, Blouin JL, Antonarakis SE, Steinfeld R, Kern I, Poretti A, Fluss J, Fokstuen S

Abstract
Neuronal ceroid lipofuscinoses represent a heterogeneous group of early onset neurodegenerative disorders that are characterized by progressive cognitive and motor function decline, visual loss, and epilepsy. The age of onset has been historically used for the phenotypic classification of this group of disorders, but their molecular genetic delineation has now enabled a better characterization, demonstrating significant genetic heterogeneity even among individuals with a similar phenotype. The rare Congenital Neuronal Ceroid Lipofuscinosis (CLN10) caused by mutations in the CTSD gene encoding for cathepsin D is associated with a dramatic presentation with onset before or around birth. We report on a female born to consanguineous parents who presented at birth with severe neonatal encephalopathy with massive cerebral and cerebellar shrinking on magnetic resonance imaging. Whole exome sequencing with targeted bioinformatic analysis of a panel of genes associated with prenatal/perinatal onset of neurodegenerative disease was performed and revealed the presence of a novel homozygous in-frame deletion in CTSD. Additional functional studies further confirmed the pathogenic character of this variant and established the diagnosis of CLN10 in the patient.

PMID: 29284168 [PubMed - as supplied by publisher]

Microvillus Inclusion Disease Variant in an Infant with Intractable Diarrhea.

Case Rep Gastroenterol. 2017 Sep-Dec;11(3):647-651

Authors: Alsaleem BMR, Ahmed ABM, Fageeh MA

Abstract
Microvillus inclusion disease (MVID) is a rare autosomal recessive congenital enteropathy characterized by intractable secretory diarrhea. We report a case of MVID variant with a homozygous gene mutation in syntaxin 3 (STX3). The patient is a male Saudi infant who presented shortly after birth with severe vomiting, metabolic acidosis, and mild diarrhea. Electron microscopy study for small intestinal biopsy was consistent with MVID. MYO5B gene mutation was excluded; subsequently, whole exome sequencing (WES) was performed, which revealed homozygous gene mutation in STX3. Using WES in clinical environment can be a useful tool for diagnosing difficult and rare inherited congenital enteropathies.

PMID: 29282386 [PubMed]

Functional characterization of a novel loss-of-function mutation of PRPS1 related to early-onset progressive nonsyndromic hearing loss in Koreans (DFNX1): Potential implications on future therapeutic intervention.

J Gene Med. 2016 Nov;18(11-12):353-358

Authors: Kim SY, Kim AR, Kim NK, Lee C, Han JH, Kim MY, Jeon EH, Park WY, Mittal R, Yan D, Liu XZ, Choi BY

Abstract
BACKGROUND: The symptoms of phosphoribosyl pyrophosphate synthetase 1 (PRPS1) deficiency diseases have been reported to be alleviated by medication. In the present study, we report biochemical data that favor PRPS1 deficiency-related hearing loss as a potential target for pharmaceutical treatment.
METHODS: We recruited 42 probands from subjects aged less than 15 years with a moderate degree of nonsyndromic autosomal-recessive or sporadic sensorineural hearing loss (SNHL) in at least one side. Molecular genetic testing, including targeted exome sequencing (TES) of 129 genes for deafness, and in silico prediction were performed.
RESULTS: A strong candidate variant (p.A82P) of PRPS1 is co-segregated with SNHL in X-linked recessive inheritance from one Korean multiplex SNHL family. Subsequent measurement of in vitro enzymatic activities of PRPS1 from erythrocytes of affected and unaffected family members, as well as unrelated normal controls, confirmed a pathogenic role of this variant. In detail, compared to normal hearing controls (0.23-0.26 nmol/ml/h), the proband, the affected sibling and their normal hearing mother demonstrated a significantly decreased PRPS1 enzymatic activity (0.07, 0.03 and 0.11 nmol/ml/h, respectively). This novel loss-of-function mutation of PRPS1 (p.A82P) is the ninth and sixth most reported mutation in the world and in Asia, respectively.
CONCLUSIONS: DFNX1 was found to account for approximately 2.4% (1/42) of moderate SNHL in a Korean pediatric population. Confirmation of PRPS1 activity deficiency and an audiologic phenotype that initially begins in a milder form of SNHL, as in our family, should indicate the need for rigorous genetic screening as early as possible.

PMID: 27886419 [PubMed - indexed for MEDLINE]

Novel De Novo Mutations in KIF1A as a Cause of Hereditary Spastic Paraplegia With Progressive Central Nervous System Involvement.

J Child Neurol. 2016 Aug;31(9):1114-9

Authors: Hotchkiss L, Donkervoort S, Leach ME, Mohassel P, Bharucha-Goebel DX, Bradley N, Nguyen D, Hu Y, Gurgel-Giannetti J, Bönnemann CG

Abstract
Hereditary spastic paraplegias are a clinically and genetically heterogeneous group of disorders characterized by lower extremity spasticity and weakness. Recently, the first de novo mutations in KIF1A were identified in patients with an early-onset severe form of complicated hereditary spastic paraplegia. We report two additional patients with novel de novo mutations in KIF1A, hereby expanding the genetic spectrum of KIF1A-related hereditary spastic paraplegia. Both children presented with spastic paraplegia and additional findings of optic nerve atrophy, structural brain abnormalities, peripheral neuropathy, cognitive/language impairment, and never achieved ambulation. In particular, we highlight the progressive nature of cerebellar involvement as captured on sequential magnetic resonance images (MRIs), thus linking the neurodegenerative and spastic paraplegia phenotypes. Exome sequencing in patient 1 and patient 2 identified novel heterozygous missense mutations in KIF1A at c.902G>A (p.R307Q) and c.595G>A (p.G199 R), respectively. Therefore, our report contributes to expanding the genotypic and phenotypic spectrum of hereditary spastic paraplegia caused by mutations in KIF1A.

PMID: 27034427 [PubMed - indexed for MEDLINE]

Genetic Progression of High Grade Prostatic Intraepithelial Neoplasia to Prostate Cancer.

Eur Urol. 2016 May;69(5):823-30

Authors: Jung SH, Shin S, Kim MS, Baek IP, Lee JY, Lee SH, Kim TM, Lee SH, Chung YJ

Abstract
BACKGROUND: Although high grade prostatic intraepithelial neoplasia (HGPIN) is considered a neoplastic lesion that precedes prostate cancer (PCA), the genomic structures of HGPIN remain unknown.
OBJECTIVE: Identification of the genomic landscape of HGPIN and the genomic differences between HGPIN and PCA that may drive the progression to PCA.
DESIGN, SETTINGS, AND PARTICIPANTS: We analyzed 20 regions of paired HGPIN and PCA from six patients using whole-exome sequencing and array-comparative genomic hybridization.
OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Somatic mutation and copy number alteration (CNA) profiles of paired HGPIN and PCA were measured and compared.
RESULTS AND LIMITATIONS: The number of total mutations and CNAs of HGPINs were significantly fewer than those of PCAs. Mutations in FOXA1 and CNAs (1q and 8q gains) were detected in both HGPIN and PCA ('common'), suggesting their roles in early PCA development. Mutations in SPOP, KDM6A, and KMT2D were 'PCA-specific', suggesting their roles in HGPIN progression to PCA. The 8p loss was either 'common' or 'PCA-specific'. In-silico estimation of evolutionary ages predicted that HGPIN genomes were much younger than PCA genomes. Our data show that PCAs are direct descendants of HGPINs in most cases that require more genomic alterations to progress to PCA. The nature of heterogeneous HGPIN population that might attenuate genomic signals should further be studied.
CONCLUSIONS: HGPIN genomes harbor relatively fewer mutations and CNAs than PCA but require additional hits for the progression.
PATIENT SUMMARY: In this study, we suggest a systemic diagram from high grade prostatic intraepithelial neoplasia (HGPIN) to prostate cancer (PCA). Our results provide a clue to explain the long latency from HGPIN to PCA and provide useful information for the genetic diagnosis of HGPIN and PCA.

PMID: 26542946 [PubMed - indexed for MEDLINE]

Genomic Perturbations Reveal Distinct Regulatory Networks in Intrahepatic Cholangiocarcinoma.

Hepatology. 2017 Dec 26;:

Authors: Nepal C, O'Rourke CJ, Oliveira DV, Taranta A, Shema S, Gautam P, Calderaro J, Barbour A, Raggi C, Wennerberg K, Wang XW, Lautem A, Roberts LR, Andersen JB

Abstract
Intrahepatic cholangiocarcinoma (iCCA) remains a highly heterogeneous malignancy that has eluded effective patient stratification to date. The extent to which such heterogeneity can be influenced by individual driver mutations remains to be evaluated. Here, we analyzed genomic (whole-exome sequencing, targeted exome sequencing) and epigenomic data from 496 patients, and used the three most recurrently mutated genes to stratify patients (IDH, KRAS, TP53, 'undetermined'). Using this molecular dissection approach, each subgroup was determined to possess unique mutational signature preferences, co-mutation profiles and enriched pathways. High-throughput drug repositioning in seven patient-matched cell lines, chosen to reflect the genetic alterations specific for each patient group, confirmed in silico predictions of subgroup-specific vulnerabilities linked to enriched pathways. Intriguingly, patients lacking all 3 mutations ('undetermined') harbored the most extensive structural alterations while IDH mutant tumors displayed the most extensive DNA methylome dysregulation, consistent with previous findings.
CONCLUSION: Stratification of iCCA patients based on occurrence of mutations in three classifier genes (IDH, KRAS, TP53) revealed unique oncogenic programs (mutational, structural, epi-mutational) that influence pharmacologic response in drug repositioning protocols. This genome dissection approach highlights the potential of individual mutations to induce extensive molecular heterogeneity and could facilitate advancement of therapeutic response in this dismal disease. This article is protected by copyright. All rights reserved.

PMID: 29278425 [PubMed - as supplied by publisher]

Novel Mutations in CFAP44 and CFAP43 Cause Multiple Morphological Abnormalities of the Sperm Flagella (MMAF).

Reprod Sci. 2017 Jan 01;:1933719117749756

Authors: Sha YW, Wang X, Xu X, Su ZY, Cui Y, Mei LB, Huang XJ, Chen J, He XM, Ji ZY, Bao H, Yang X, Li P, Li L

Abstract
Multiple morphological abnormalities of the sperm flagella (MMAF) is a rare disease that causes primary infertility. However, the genetic causes for approximately half of MMAF cases are unknown. Whole exome sequencing analysis of the 27 patients with MMAF identified several CFAP44 mutations (3 homozygous: c.2935_2944del: p.D979*, c.T1769A: p.L590Q, c.2005_2006del: p.M669Vfs*13; and putative compound heterozygous: c.G3262A: p.G1088S and c.C1718A: p.P573H.) and CFAP43 acceptor splice-site deletion (c.3661-2A>-) mutations in 5 and 1 patients, respectively. Real-time quantitative polymerase chain reaction assays also demonstrated that CFAP44 expression was very weak in patient (P)1 and P3, and CFAP43 expression was lower in P6 than in the control. Immunofluorescence analysis of CFAP43 showed lower CFAP43 protein expression levels in P6 than in the normal control. This study demonstrated that biallelic mutations in CFAP44 and CFAP43 cause MMAF. These results provide researchers with a new insight to understand the genetic etiology of MMAF and to identify new loci for genetic counselling of MMAF.

PMID: 29277146 [PubMed - as supplied by publisher]

lncRNA MIR100HG-derived miR-100 and miR-125b mediate cetuximab resistance via Wnt/β-catenin signaling.

Nat Med. 2017 Nov;23(11):1331-1341

Authors: Lu Y, Zhao X, Liu Q, Li C, Graves-Deal R, Cao Z, Singh B, Franklin JL, Wang J, Hu H, Wei T, Yang M, Yeatman TJ, Lee E, Saito-Diaz K, Hinger S, Patton JG, Chung CH, Emmrich S, Klusmann JH, Fan D, Coffey RJ

Abstract
De novo and acquired resistance, which are largely attributed to genetic alterations, are barriers to effective anti-epidermal-growth-factor-receptor (EGFR) therapy. To generate cetuximab-resistant cells, we exposed cetuximab-sensitive colorectal cancer cells to cetuximab in three-dimensional culture. Using whole-exome sequencing and transcriptional profiling, we found that the long non-coding RNA MIR100HG and two embedded microRNAs, miR-100 and miR-125b, were overexpressed in the absence of known genetic events linked to cetuximab resistance. MIR100HG, miR-100 and miR-125b overexpression was also observed in cetuximab-resistant colorectal cancer and head and neck squamous cell cancer cell lines and in tumors from colorectal cancer patients that progressed on cetuximab. miR-100 and miR-125b coordinately repressed five Wnt/β-catenin negative regulators, resulting in increased Wnt signaling, and Wnt inhibition in cetuximab-resistant cells restored cetuximab responsiveness. Our results describe a double-negative feedback loop between MIR100HG and the transcription factor GATA6, whereby GATA6 represses MIR100HG, but this repression is relieved by miR-125b targeting of GATA6. These findings identify a clinically actionable, epigenetic cause of cetuximab resistance.

PMID: 29035371 [PubMed - indexed for MEDLINE]